Transformations of thio­carbonyls into alkenes via Barton–Kellogg olefination

Linden, A.; Egli, D.H.; Heimgartner, H.

doi:10.1107/S2053229625002074

research papers

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 81| Part 4| April 2025| Pages 238-245

https://doi.org/10.1107/S2053229625002074

Open

access

Transformations of thiocarbonyls into alkenes via Barton–Kellogg olefination

Anthony Linden,^a ^* Daniel H. Egli ^a ‡ and Heinz Heimgartner ^a

^aDepartment of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
^*Correspondence e-mail: [email protected]

Edited by J. White, The University of Melbourne, Australia (Received 20 February 2025; accepted 4 March 2025; online 14 March 2025)

The transformation of a thiocarbonyl compound into an alkene by stepwise treatment with a diazo compound and triphenylphosphane is known as Barton–Kellogg olefination. As a model reaction, 4,4′-dimethoxythiobenzophenone and diazocyclohexane were used to prepare [bis(4-methoxyphenyl)methylidene]cyclohexane, C₂₁H₂₄O₂. The crystal structure of the latter, as well as that of the intermediate thiirane, 2,2-bis(4-methoxyphenyl)-1-thiaspiro[2.5]octane, C₂₁H₂₄O₂S, have been determined and their molecular conformations and geometries are generally consistent with those of related structures in the literature. Variations in the influence of four substituents on crowded thiirane rings are minimal and the main differences are noted in the presence of bulky tert-butyl substituents. The conformation of the intermediate thiirane is influenced by weak intramolecular C—H⋯S interactions. A three-dimensional supramolecular structure of the methylene cyclohexane compound results from the combination of three distinct weak C—H⋯π interactions. Under similar reaction conditions, 5-phenyl-3H-1,2-dithiole-3-thione has been transformed into 3-[bis(4-methoxyphenyl)methylidene]-5-phenyl-3H-1,2-dithiole, C₂₄H₂₀O₂S₂, by treatment with bis(4-methoxyphenyl)diazomethane. The crystal structure of the 1,2-dithiole product reveals a molecule with an all-trans 2,4-hexadiene core, in which the Csp²—Csp² bond lengths display an alternating character that suggests little delocalization of the double bonds. The 1,2-dithiole ring is nearly planar, with just a slight puckering into an envelope form. Two weak C—H⋯π and one C—H⋯O interaction link the molecules into thick two-dimensional supramolecular layers.

Keywords: crystal structure; dithiole; thiirane; Barton–Kellogg; olefination.

CCDC references: 2428894; 2428893; 2428892

1. Introduction

In the synthesis of organic compounds, olefination reactions play a prominent role (see, for example, Bodwell & Nandaluru, 2012 ; Takeda, 2014 ; Hu & Wang, 2019 ). The most well-known ones are transformations of carbonyl compounds 1 into alkenes 2 (Scheme 1), such as, among others, the Wittig reaction (Murphy & Brennan, 1988 ; Maryanoff & Reitz, 1989 ; Byrne & Gilheany, 2013 ; Rocha et al., 2018 ; Heravi et al., 2020 ), the Peterson olefination (Ager, 1984 ; van Staden et al., 2002 ; Britten & McLaughlin, 2020 ), the Julia–Kocienski olefination (Baudin et al., 1993 ; Sakaine et al., 2023 ; Chrenko & Pospíšil, 2024 ) and the McMurry reaction (Ephritikhine, 1998 ; Duan et al., 2006 ; Bongso et al., 2022 ).

The analogous transformation of thiocarbonyl derivatives into alkenes is known as Barton–Kellogg olefination (Barton et al., 1974 ; Kellogg, 1976 ; Guziec & Sanfilippo, 1988 ; Schmidt & Sparr, 2021 ). The mechanism of this so-called `twofold extrusion reaction' has been reported by Huisgen et al. (1984 ): the initial [3+2] cycloaddition of the thiocarbonyl compound 3 and the diazo compound 4 leads to the 1,3,4-thiadiazoline 5 (Scheme 2). Elimination of N₂ yields the thiirane 7 via electrocyclization of the intermediate thiocarbonyl ylide 6, and the final alkene 2c is formed by extrusion of sulfur. Recently, this reaction sequence has been supported by theoretical studies (Mlostoń et al., 2020 ; Burns et al., 2021 ; Seif et al., 2022 ).

It has also been communicated that the alkene 2, as well as the intermediates 5 and 7, can be isolated as final products depending on the kind of substituents and the reaction conditions. For example, we have shown that in the reaction of the heterocyclic thione 8, a 1,3,4-thiadiazoline-5-thione, with bis(tert-butyl)diazomethane (4a) in dichloromethane (CH₂Cl₂) at 273 K, the primary cycloadduct 5a can be isolated in high yield, whereas in the analogous reaction with diphenyldiazomethane (4b) in tetrahydrofuran (THF) at room temperature, spontaneous elimination of N₂ was observed and thiirane 7a was obtained exclusively (Mlostoń et al., 1994 ). Furthermore, the reaction of 8 with 2-diazopropane (4c) in pentane at 275–276 K and workup at room temperature yielded the alkene derivative 2d (Mlostoń & Heimgartner, 1992 ) (Scheme 3). In the crude reaction mixture, the corresponding intermediates of type 5 and 7 could be detected by ¹H NMR spectroscopy. Finally, treatment of 8 with diazomethane in diethyl ether at 195 K led to a mixture of the corresponding thiirane and alkene derivative of type 7 and 2, together with products of the dimerization and [3+2] cycloaddition of the intermediate thiocarbonyl ylide of type 6 (Kägi et al., 1993 ).

Within our studies on [3+2] cycloadditions with thiocarbonyl derivatives, we used the Barton–Kellogg olefination frequently for the preparation of sterically crowded alkenes (e.g. Kägi, Mlostoń et al., 1998 ; Egli et al., 2007 ; Mlostoń et al., 2002 , 2016 , 2018 ). As a model reaction, we transformed 4,4′-dimethoxythiobenzophenone (9) (Pedersen et al., 1978 ) via the `twofold extrusion reaction' with diazocyclohexane into [bis(4-methoxyphenyl)methylidene]cyclohexane (11; Scheme 4). In this case, the intermediate thiirane 10 was also isolated in a two-step reaction sequence. The crystal structures of 10 and 11 were determined by X-ray diffraction analysis.

In an analogous manner, the known 5-phenyl-3H-1,2-dithiole-3-thione (12) (Wei, 1986 ; Mathur et al., 2004 ; Koley et al., 2016 ; Rakitin, 2021 ) was transformed into 3-[bis(4-methoxyphenyl)methylidene]-5-phenyl-3H-1,2-dithiole (13, Scheme 5) by treatment with bis(4-methoxyphenyl)diazomethane in benzene without isolation of the intermediate. The molecular structure of 13 was confirmed by a crystal structure analysis.

2. Experimental

2.1. Synthesis and crystallization

2.1.1. 2,2-Bis(4-methoxyphenyl)-1-thiaspiro[2.5]octane (10)

To a solution of 4,4′-dimethoxythiobenzophenone (0.50 g, 2 mmol) (9) (Pedersen et al., 1978) in CH₂Cl₂ (20 ml) at room temperature were added dropwise a solution (15 ml) of diazocyclohexane (ca 2–5 mmol) in CH₂Cl₂. Immediate evolution of N₂ was observed and the colour of the mixture changed from blue to yellow. After stirring for 30 min, the solvent was evaporated and the residue was purified chromatographically [MPLC, hexane/ethyl acetate (AcOEt), 8:1 v/v] and crystallized from chloroform (CHCl₃). Yield of 10: 421 mg (85%). Crystals suitable for X-ray crystal structure analysis were obtained by recrystallization from CHCl₃.

2.1.2. [Bis(4-methoxyphenyl)methylidene]cyclohexane (11)

A solution of 10 (149 mg, 0.58 mmol) and triphenylphosphane (Ph₃P, 154 mg, 0.6 mmol) in THF (60 ml) was heated to reflux for 60 h, during which additional Ph₃P (0.6 mmol) was added after each period of 5 h. After evaporation of the solvent, the crude product was purified chromatographically (SiO₂, hexane/AcOEt, 15:1 v/v). Yield of 11: 166 mg (92%). Crystals suitable for X-ray crystal structure analysis were obtained by recrystallization from CH₂Cl₂/hexane.

2.1.3. 3-[Bis(4-methoxyphenyl)methylidene]-5-phenyl-3H-1,2-dithiole (13)

To a solution of 5-phenyl-3H-1,2-dithiole-3-thione (ca 105 mg, 0.5 mmol) (12) in benzene (30 ml) were added bis(4-methoxyphenyl)diazomethane (ca 152 mg, 0.6 mmol) at room temperature. After stirring for 4 d, the mixture was heated to 323 K. Evaporation of the solvent and recrystallization of the residue from hexane/AcOEt yielded suitable crystals for X-ray crystal structure analysis.

2.2. Analytical and spectroscopic data

Compound 10: colourless crystals, m.p. 368–369 K; IR (KBr): 2950 (m), 2925 (vs), 2851 (s), 2834 (m), 1605 (s), 1510 (vs), 1463 (s), 1439 (s), 1286 (s), 1246 (vs), 1184 (s), 1172 (s), 1114 (m), 1032 (s), 838 (s), 824 (s), 813 (s) cm⁻¹; ¹H NMR (CDCl₃): δ 7.40 (d, J = 8.9, 4 arom. H), 6.76 (d, J = 8.9, 4 arom. H), 3.73 (s, 2 MeO), 2.07–1.17 (m, 5 CH₂); ¹³C NMR (CDCl₃): δ 158.3 (s, 2 arom. C—OMe), 134.8 (s, 2 arom. C), 130.3, 113.3 (2d, 8 arom. CH), 67.2 (s, C2), 62.8 (s, C3), 55.2 (q, 2 MeO), 37.1 (t, 2 CH₂), 26.5 (t, 2 CH₂), 25.8 (t, CH₂); CI–MS: 309 (100, [M – S]⁺).

Compound 11: colourless crystals, m.p. 382–383 K; IR (KBr): 2962 (s), 2927 (vs), 2913 (m), 2840 (s), 1608 (s), 1510 (vs), 1457 (s), 1447 (s), 1308 (m), 1301 (s), 1287 (s), 1279 (s), 1243 (vs), 1184 (m), 1171 (vs), 1107 (m), 1033 (vs), 838 (s), 828 (vs), 812 (s) cm⁻¹; ¹H NMR (CDCl₃): δ 7.02 (d, J = 8.9, 4 arom. H), 6.80 (d, J = 8.9, 4 arom. H), 3.78 (s, 2 MeO), 2.26–2.24 (m, 2 CH₂), 1.59–1.57 (m, 3 CH₂); ¹³C NMR (CDCl₃): δ 157.7 (s, 2 arom. C—OMe), 138.3, 133. 4 (2 C), 135.9 (s, 2 arom. C), 130.9, 113.2 (2d, 8 arom. CH), 55.1 (q, 2 MeO), 32.5 (t, 2 CH₂), 28.7 (t, 2 CH₂), 26.9 (t, CH₂); CI–MS: 309 (100, [M]⁺).

Compound 13: red crystals.

2.3. Refinement

Crystal data, data collection and structure refinement details for 10, 11 and 13 are summarized in Table 1. For all structures, the methyl H atoms were constrained to an ideal geometry (C—H = 0.98 Å), with U_iso(H) = 1.5U_eq(C), but were allowed to rotate freely about the parent C—C bonds. All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C—H distances of 0.95 (aromatic, alkene) or 0.99 Å (methylene), and U_iso(H) = 1.2U_eq(C).

Table 1
Experimental details

For all structures: Z = 4. Experiments were carried out at 160 K with Mo Kα radiation using a Nonius KappaCCD area-detector diffractometer. Absorption was corrected for by the multi-scan method (Blessing, 1995 ). H-atom parameters were constrained.

	10	11	13
Crystal data
Chemical formula	C₂₁H₂₄O₂S	C₂₁H₂₄O₂	C₂₄H₂₀O₂S₂
M_r	340.46	308.40	404.52
Crystal system, space group	Monoclinic, P2₁/c	Monoclinic, P2₁/c	Monoclinic, P2₁/n
a, b, c (Å)	10.6815 (2), 8.3698 (1), 21.0120 (3)	12.3664 (2), 5.3819 (1), 25.5086 (5)	15.2746 (2), 6.6094 (1), 19.8754 (3)
β (°)	103.5641 (8)	93.4911 (10)	93.5489 (9)
V (Å³)	1826.12 (5)	1694.57 (5)	2002.69 (5)
μ (mm⁻¹)	0.19	0.08	0.28
Crystal size (mm)	0.28 × 0.25 × 0.15	0.25 × 0.15 × 0.08	0.30 × 0.25 × 0.15

Data collection
T_min, T_max	0.840, 0.978	0.809, 0.999	0.863, 0.961
No. of measured, independent and observed [I > 2σ(I)] reflections	36506, 4168, 3526	30267, 2994, 2356	45139, 4597, 3564
R_int	0.053	0.079	0.060
(sin θ/λ)_max (Å⁻¹)	0.649	0.595	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.035, 0.095, 1.04	0.057, 0.151, 1.06	0.042, 0.112, 1.06
No. of reflections	4165	2992	4597
No. of parameters	219	210	255
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.26	0.44, −0.21	0.29, −0.34
Computer programs: COLLECT (Nonius, 2000 ), DENZO-SMN (Otwinowski & Minor, 1997 ), SHELXS97 (Sheldrick, 2008 ), SIR92 (Altomare et al., 1994 ), SHELXL2019 (Sheldrick, 2015 ), OLEX2 (Dolomanov et al., 2009 ), publCIF (Westrip, 2010 ) and PLATON (Spek, 2020).

3. Results and discussion

The molecular structure of the intermediate 10 (Fig. 1) reveals that Barton–Kellogg olefination of the thiobenzophenone 9 (Scheme 4) initially has formed a three-membered thiirane ring, which subsequently extrudes sulfur to give the fully-substituted alkene 11. In the crystal, the molecule of 10 has approximate noncrystallographic C_s symmetry across the plane of the thiirane ring, with a Continuous Symmetry Measure (Zabrodsky et al., 1993 ) of 0.047 Å and a root-mean-square deviation of 0.022 Å [unit weights; calculations performed with the program PLATON (Spek, 2020 )]. The 4-methoxy groups are nearly coplanar with their parent arene rings, with C14—O11—C11—C10 and C21—O18—C18—C17 torsion angles of −7.65 (19) and 4.9 (2)°, respectively. The mean planes of the arene rings containing atoms C8–C13 and C15–C20 make dihedral angles of 74.86 (6) and 73.65 (6)°, respectively, with the plane defined by thiirane ring atom C1 and the ipso and para C atoms of the two arene rings. Such an arrangement might be induced by one ortho H atom in each arene ring having a modest intramolecular interaction with atom S1 [C13—H13⋯S1, with H13⋯S1 = 2.85 Å, C13⋯S1 = 3.2119 (13) Å and C13—H13⋯S1 = 104°; C20—H20⋯S1 with H20⋯S1 = 2.83 Å, C20⋯S1 = 3.1963 (13) Å and C20—H20⋯S1 = 104°]. The consequence of this is that the distance between the other ortho H atoms of these two rings, H9 and H16, is 2.33 Å. There are no noteworthy intermolecular interactions of any type.

Figure 1
View of the molecule of 10, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by spheres of arbitrary size.

The Cambridge Structural Database (CSD, Version 5.46, update of November 2024, Groom et al., 2016 ) records 28 unique crystal structures of fully-substituted organic thiirane compounds, which have atomic coordinates in the database, no errors and R < 0.075. Of these, 24 have two aromatic substituents at one or both of the ring C atoms, albeit for 16 of them, the aromatic rings are connected to one another as part of a spiro(dibenzo[a,d][7]annulene), spiro(xanthene), spiro(fluorene), or related, substituent, which imposes steric constraints on the C_ar—C—C_ar bond angle at the spiro C atom. Concerning substituents at the other C atom of the thiirane ring, of the above 24 structures, seven have neither aromatic rings, as part of a larger spiro substituent or otherwise, nor a methylene group bonded to the thiirane ring. There is only one example (CSD refcode MEFFAF; Mlostoń et al., 2006 ) of a spirocyclic aliphatic substituent on the thiirane ring that is not further fused with an aromatic ring, such as spiro[cyclopenta[a]naphthalene]. That single example contains an aliphatic spiro(norbornane) substituent on one thiirane C atom, as well as two phenyl substituents on the other thiirane ring C atom and thus may be considered as the closest relative, for which a crystal structure has been reported, to 10 with its unsubstituted spiro(cyclohexyl) group. The simplest fully-substituted thiirane structure is that of 2,2-di-tert-butyl-3,3-diphenylthiirane (DTBPTR01; Mugnoli & Simonetta, 1976 ), in which none of the substituents form a spirocyclic junction with the thiirane ring and two bulky tert-butyl substituents bond to one of the thiirane C atoms. One further example with a single tert-butyl substituent is NURYEE (Kägi, Linden et al., 1998 ).

The geometries of the thiirane ring core of 10, MEFFAF, DTBPTR01 and NURYEE are listed in Table 2, alongside that of unsubstituted gas-phase thiirane (ethylene sulfide) derived from its experimental microwave spectrum (Cunningham et al., 1951 ) and matched exactly by an ab initio MO–SCF study (Rohmer & Roos, 1975 ). The geometry of the thiirane ring of 10 is consistent with that in the three other crystal structures, except that the thiirane ring C—C bond (C1—C2 in 10) is slightly longer in the two tert-butyl-substituted compounds DTBPTR01 and NURYEE. Indeed, the exo C_ring—C bonds are significantly longer in the two tert-butyl-substituted compounds than any of the other such bonds in the compounds in Table 2. These observations could be attributable to the crowding caused by the bulkiness of the tert-butyl substituents, whereas arene-based substituents are only bulky in one or two dimensions. None of the bond angles within the thiirane ring show any significant variation across the four crystal structures in Table 2. The exo C—C_ring—C angles are less informative, as they are influenced not only by the bulkiness of the substituents, but also by potential geometrical constraints within any spirocyclic linkages.

Table 2
Selected geometric parameters (Å, °) for 10 and related compounds

The atom numbers refer to the structure model for 10. Other atom-numbering schemes may have been used for the other structures; the entries refer to the corresponding chemical parts of the structures.

	10	MEFFAF*	DTBPTR01	NURYEE	Microwave**	22 structures without tert-butyl
						Range, mean
S1—C1	1.8381 (12)	1.8185 (15), 1.8233 (15)	1.823 (2)	1.818 (2)	1.819	1.802–1.856, 1.824 (11)
S1—C2	1.8493 (12)	1.8334 (16), 1.8245 (16)	1.847 (2)	1.841 (2)	1.819	1.785–1.854, 1.826 (17)
C1—C2	1.5041 (18)	1.516 (2), 1.508 (2)	1.549 (3)	1.539 (2)	1.492	1.508–1.556, 1.535 (13)
C1—C8	1.5152 (16)	1.512 (2), 1.507 (2)	1.516 (3)	1.505 (3)	–	1.489–1.543, 1.513 (11)
C1—C15	1.5151 (17)	1.514 (2), 1.525 (2)	1.535 (3)	1.509 (3)	–	1.489–1.543, 1.513 (11)
C2—C3	1.5160 (17)	1.530 (2), 1.528 (2)	1.588 (3)	1.567 (4)	–	1.490–1.562, 1.519 (13)
C2—C7	1.5156 (17)	1.532 (2), 1.541 (2)	1.598 (3)	1.542 (4)	–	1.490–1.562, 1.519 (13)
C1—S1—C2	48.14 (6)	49.05 (7), 48.84 (7)	49.9 (9)	49.76 (8)	65.8	48.8–50.55, 49.7 (5)
S1—C2—C1	65.54 (7)	65.99 (8), 65.62 (8)	64.2 (9)	64.35 (10)	not given	63.9–66.4, 65.3 (7)
S1—C1—C2	66.32 (7)	64.96 (8), 64.54 (8)	65.9 (9)	65.89 (11)	not given	63.9–66.2, 65.0 (7)
C8—C1—C15	113.92 (10)	112.57 (13), 112.48 (13)	104.0 (2)	108.23 (16)	–	104.0–116.7, 111 (4)
C3—C2—C7	113.01 (11)	102.50 (12), 102.54 (12)	118.3 (2)	110.94 (17)	–	102.5–118.8, 111 (5)
Notes: () two molecules in the asymmetric unit. () Structure from experimental microwave data (Cunningham et al.*, 1951); result reproduced exactly by MO–SCF calculations (Rohmer & Roos, 1975).

Table 2 also lists the ranges and means of the discussed geometric parameters for the 22 structures from the above-mentioned CSD search that do not include a tert-butyl substituent. This shows that the molecular geometry of the core of 10 is consistent with those of a broader range of thiirane structures. On the other hand, the ring in unsubstituted thiirane obtained from microwave data and ab initio MO–SCF calculations shows a significantly shorter C—C bond and larger C—S—C angle than in the crystal structures listed in Table 2. The electronic influence and steric effects of the substituents are probably responsible for this observation.

The molecular structure of alkene 11 (Fig. 2), the sulfur extrusion product obtained from 10 (Scheme 4), shows exo C_ring—C_ar bonds slightly shorter than in 10 (Table 3). This might be attributed to some delocalization of the alkene bond with the arene rings, although the mean planes of the arene rings containing atoms C8–C13 and C15–C20 are tilted significantly out of the plane containing alkene atom C1 and both arene ring ipso and para C atoms, with dihedral angles of 52.96 (9) and 61.85 (9)°, respectively. These rings now tilt in an opposite sense to each other, unlike in 10, thereby avoiding any short interring H⋯H distances. Also, the electron-withdrawing effect of the S atom in 10 could lead to the slightly longer exo C_ring—C_ar bonds to the arene substituents, although this does not appear to influence the length of the exo C_ring—C_alkyl bonds to the spiro(cyclohexyl) substituent. The substituents at each end of the central alkene bond indicate a small twist about the latter, with a dihedral angle of 7.1 (3)°. The 4-methoxy groups are nearly coplanar with their parent arene rings, with C14—O11—C11—C10 and C21—O18—C18—C17 torsion angles of 9.1 (3) and 4.1 (3)°, respectively.

Table 3
Selected geometric parameters (Å, °) for 11 and related compounds

The atom numbers refer to the structure model for 11. Other atom-numbering schemes may have been used for the other structures; the entries refer to the corresponding chemical parts of the structures.

	11	10	AOPCHY	DEQTOJ
C1—C2	1.340 (3)	1.5041 (18)	1.339	1.344 (3)
C1—C8	1.498 (3)	1.5152 (16)	1.495	1.511 (3)
C1—C15	1.495 (3)	1.5151 (17)	1.542	1.505 (3)
C2—C3	1.510 (3)	1.5160 (17)	1.500	1.513 (3)
C2—C7	1.514 (3)	1.5156 (17)	1.549	1.515 (3)
C8—C1–C15	113.49 (16)	113.92 (10)	115.4	117.8 (2)
C3—C2–C7	111.92 (17)	113.01 (11)	112.8	112.3 (2)

Figure 2
View of the molecule of 11, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by spheres of arbitrary size.

The crystal structure of 11 is supported by three weak C—H⋯π interactions involving as donors two cyclohexyl and one methoxy C—H. Both of the 4-methoxyphenyl rings act as acceptors for these interactions (Table 4). The combination of these intermolecular interactions gives a three-dimensional supramolecular structure. There are no significant π–π interactions.

Table 4
Intermolecular C—H⋯π interactions (Å, °) for 11

Cg1 and Cg2 are the centroids of the C8–C13 and C15–C20 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4B⋯Cg2ⁱ	0.99	2.96	3.888 (3)	157
C6—H6A⋯Cg1ⁱⁱ	0.99	2.96	3.820 (3)	146
C14—H14A⋯Cg1ⁱⁱⁱ	0.98	2.88	3.737 (2)	147
Symmetry codes: (i) −x + 1, −y, −z; (ii) −x + 1, y − $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (iii) −x + 2, y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ .

The CSD records the crystal structures of two molecules that are closely related to 11. The relevant geometric parameters for the compounds containing bis(4-acetoxyphenyl) (AOPCHY; Precigoux et al., 1972 ) and bis(mesityl) (DEQTOJ; Sun et al., 2006 ) substituents, instead of the bis(4-methoxy) groups present in 11, are included in Table 3 and are consistent with those of 11.

An analogous Barton–Kellogg olefination starting from the dithiole-3-thione 12 led to the 3-methylene-1,2-dithiole 13 (Scheme 5). The molecular structure of 13 reveals an all-trans 2,4-hexadiene core from atom C7 through to C20 (Fig. 3), in which the Csp²—Csp² bond lengths clearly display an alternating character that suggests little delocalization of the double bonds (Table 5). The 1,2-dithiole ring is nearly planar, with just a slight puckering into an envelope form, with atom S1 as the envelope flap being 0.1985 (5) Å out of the plane of the other four ring atoms. The mean plane of the arene substituent at atom C3 of the 1,2-dithiole ring is tilted significantly out of the plane of the 1,2-dithiole ring, calculated excluding atom S1, with a dihedral angle of 31.20 (10)°. Considering the formal alkene nature of the C5—C6 bond, there is a small twist between the planes of the substituents at each end of the alkene bond, with a dihedral angle between the planes defined by atoms S1/C4/C5 and C6/C13/C20 of 6.0 (2)°. The mean planes of the 4-methoxyphenyl rings containing atoms C13–C18 and C20–C25, calculated without considering the methoxy groups, are tilted significantly out of the plane containing alkene atom C6 and both 4-methoxyphenyl ring ipso and para C atoms, with dihedral angles of 56.58 (8) and 35.06 (8)°, respectively. These rings tilt in an opposite sense to each other, similar to the arrangement in compound 11. The shallowness of these tilts for the arene substituent at atom C3 of the 1,2-dithiole ring and the 4-methoxyphenyl ring containing atoms C20–C25 may in part be induced by two weak intramolecular C—H⋯S interactions involving ortho C—H groups of these rings (Table 6). The 4-methoxy groups are coplanar with their parent arene rings, with C19—O16—C16—C15 and C26—O23—C23—C24 torsion angles of 2.8 (3) and −1.1 (3)°, respectively.

Table 5
Selected geometric parameters (Å, °) for 13 and related compounds

The atom numbers refer to the structure model for 13. Other atom-numbering schemes may have been used for the other structures; the entries refer to the corresponding chemical parts of the structures.

	13	GANGUX*	CPTYBN10	XPTHYC
S1—S2	2.0826 (6)	2.041 (5), 2.051 (4)	2.072 (4)	2.053
S1—C5	1.7797 (17)	1.735 (12), 1.732 (12)	1.74 (1)	1.772
S2—C3	1.7568 (17)	1.714 (11), 1.734 (12)	1.730 (8)	1.732
C3—C4	1.342 (2)	1.36 (2), 1.36 (2)	1.35 (1)	1.379
C3—C7	1.471 (2)	1.47 (2), 1.47 (2)	1.47 (1)	1.451
C4—C5	1.446 (2)	1.40 (2), 1.41 (2)	1.42 (1)	1.404
C5—C6	1.362 (2)	1.44 (2), 1.42 (2)	1.39 (1)	1.404
C6—C13	1.492 (2)	1.41 (2), 1.39 (2)	1.40 (1)	1.451
C6—C20	1.479 (2)	1.51 (2), 1.50 (2)	–	1.394
S2—S1—C5	96.33 (6)	95.6 (9), 96.0 (4)	96.5 (9)	95.8
S1—S2—C3	94.22 (6)	96.2 (8), 95.6 (5)	95.0 (9)	96.1
S2—C3—C4	116.95 (13)	114.6 (10), 114.9 (10)	115.4 (9)	115.0
C3—C4—C5	120.21 (15)	120.6 (11), 120.1 (12)	121.2 (9)	120.4
S1—C5—C4	111.42 (12)	112.9 (11), 113.4 (9)	111.9 (9)	112.7
C13—C6—C20	116.80 (14)	126.3 (11), 124.8 (10)	–	118.2
Note: (*) two 1,2-dithiole-3H-3-ylidene entities in the cation.

Table 6
Intramolecular C—H⋯S and intermolecular C—H⋯O and C—H⋯π interactions (Å, °) for 13

Cg3 and Cg4 are the centroids of the C13–C18 and C20–C25 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8⋯S2	0.95	2.77	3.1236 (19)	103
C25—H25⋯S1	0.95	2.59	3.0503 (19)	110
C8—H8⋯O16ⁱ	0.95	2.59	3.413 (2)	146
C10—H10⋯Cg3ⁱⁱ	0.99	2.96	3.888 (3)	157
C14—H14⋯Cg4ⁱⁱⁱ	0.99	2.96	3.820 (3)	146
Symmetry codes: (i) x + $[{1\over 2}]$ , −y − $[{1\over 2}]$ , z + $[{1\over 2}]$ ; (ii) −x + 2, −y − 1, −z; (iii) x, y − 1, z.

Figure 3
View of the molecule of 13, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by spheres of arbitrary size.

The crystal structure of 13 is supported by two weak C—H⋯π interactions involving as donors the para H atom on the phenyl ring and an ortho H atom on a 4-methoxyphenyl ring. Both of the 4-methoxyphenyl rings act as acceptors for these interactions (Table 6). Additionally, there is one intermolecular C—H⋯O interaction involving, as the donor, the same C8—H donor as involved in one of the intramolecular C—H⋯S interactions and a methoxy O atom as the acceptor. The combination of these three intermolecular interactions links the molecules into thick two-dimensional supramolecular layers which extend parallel to the (10 $[\overline{1}]$ ) plane. There are no significant π–π interactions.

The CSD lists 21 unique crystal structures with an organic 1,2-dithiole-3H-3-ylidene core, which have atomic coordinates in the database and no errors (13 with R < 0.075). All of these have 5-substituted 1,2-dithiole rings. Of these structures, 18 have substituents containing S (1,2-dithiole or thione), O (carbonyl, aldehyde or nitro) or N (hydrazine, nitroso or pyridyl) atoms adjacent to the 1,2-dithiole ring, such that these heteroatoms weakly interact with a 1,2-dithiole S atom to complete an additional fused five-membered ring, thereby potentially inducing distortion of bond distances and angles and rendering comparison with those of 13 impractical. Selected geometric parameters of the remaining three structures are compared with those of 13 in Table 5. Firstly, 2-cyano-3-phenyl-4-(5-phenyl-1,2-dithiole-3-ylidene)-Δ²-butyronitrile (CPTYBN10; Nguyen-Huy-Dong & Etienne, 1978 ) has just one ylidene substituent, but with potential for additional conjugation with a further alkene group, plus a phenyl substituent on the 1,2-dithiole ring. A more complex structure is that of the ionic 3-[1,3-diphenyl-3-(5-phenyl-1,2-dithiol-3-yl)propenyl-3-ylidene]-5-phenyl-1,2-dithiolium triiodide (GANGUX; Hordvik et al., 1988 ), which is essentially a dimer of the 1,2-dithiole core, each with aryl and alkene substituents on the other end of the ylidene group, and an aryl substituent on the 1,2-dithiole ring. The authors proposed that the cationic charge is delocalized across the cation. Finally, 2,6-dimethyl-5′-p-methoxyphenyl-1′,2′-dithiole-3′,4-ylidene-2,5-cyclohexadienone benzene solvate (XPTHYC; Wei et al., 1977 ), with an elevated R factor of 0.090, has a cyclohexadienone substituent on the other end of the ylidene group and a 4-methoxyphenyl substituent on the 1,2-dithiole ring. It can be concluded that the molecular geometry of the 1,2-dithiole-3H-3-ylidene core of 13 is consistent with those of these three related structures. Larger differences in the substituent C—C_ylidene bonds are a result of variations in the electronic and chemical nature of the substituent(s) at that position.

Supporting information

CCDC references: 2428894; 2428893; 2428892

Crystal structure: contains datablocks 10, 11, 13, global. DOI: https://doi.org/10.1107/S2053229625002074/wq3148sup1.cif

Structure factors: contains datablock 10. DOI: https://doi.org/10.1107/S2053229625002074/wq314810sup2.hkl

Structure factors: contains datablock 11. DOI: https://doi.org/10.1107/S2053229625002074/wq314811sup3.hkl

Structure factors: contains datablock 13. DOI: https://doi.org/10.1107/S2053229625002074/wq314813sup4.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2053229625002074/wq314810sup5.cdx

Supporting information file. DOI: https://doi.org/10.1107/S2053229625002074/wq314811sup6.cdx

Supporting information file. DOI: https://doi.org/10.1107/S2053229625002074/wq314813sup7.cdx

Supporting information file. DOI: https://doi.org/10.1107/S2053229625002074/wq314810sup8.cml

Supporting information file. DOI: https://doi.org/10.1107/S2053229625002074/wq314811sup9.cml

Supporting information file. DOI: https://doi.org/10.1107/S2053229625002074/wq314813sup10.cml

Computing details top

2,2-Bis(4-methoxyphenyl)-1-thiaspiro[2.5]octane (10) top

Crystal data top

C₂₁H₂₄O₂S	D_x = 1.238 Mg m⁻³
M_r = 340.46	Melting point: 368 K
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 10.6815 (2) Å	Cell parameters from 58148 reflections
b = 8.3698 (1) Å	θ = 1.0–27.5°
c = 21.0120 (3) Å	µ = 0.19 mm⁻¹
β = 103.5641 (8)°	T = 160 K
V = 1826.12 (5) Å³	Prism, colorless
Z = 4	0.28 × 0.25 × 0.15 mm
F(000) = 728

Data collection top

Nonius KappaCCD area-detector diffractometer	4168 independent reflections
Radiation source: Nonius FR590 sealed tube generator	3526 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.053
Detector resolution: 9 pixels mm^-1	θ_max = 27.5°, θ_min = 2.5°
φ and ω scans with κ offsets	h = −13→13
Absorption correction: multi-scan (Blessing, 1995)	k = −10→10
T_min = 0.840, T_max = 0.978	l = −26→27
36506 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.035	H-atom parameters constrained
wR(F²) = 0.095	w = 1/[σ²(F_o²) + (0.044P)² + 0.665P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
4165 reflections	Δρ_max = 0.23 e Å⁻³
219 parameters	Δρ_min = −0.26 e Å⁻³
0 restraints

Special details top

Experimental. Data collection and full structure determination done by Prof. Anthony Linden: [email protected]

Solvent used: CHCl3 Cooling Device: Oxford Cryosystems Cryostream 700 Crystal mount: on a glass fibre Mosaicity (deg.): 0.863 (1) Frames collected: 598 Seconds exposure per frame: 78 Degrees rotation per frame: 1.3 Crystal-detector distance (mm): 38.0 Client: Egli Daniel Sample code: DE281 (HG0111)

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	0.74158 (3)	0.71461 (4)	0.09887 (2)	0.02698 (10)
O11	0.89034 (9)	0.98043 (13)	0.40899 (4)	0.0363 (2)
O18	0.13992 (9)	0.98595 (13)	0.06303 (5)	0.0382 (2)
C1	0.64280 (12)	0.73223 (15)	0.15935 (6)	0.0238 (3)
C2	0.66885 (11)	0.56240 (15)	0.14291 (6)	0.0245 (3)
C3	0.56180 (12)	0.46440 (15)	0.10043 (6)	0.0274 (3)
H3A	0.507598	0.534466	0.067069	0.033*
H3B	0.506704	0.419516	0.127905	0.033*
C4	0.61573 (13)	0.32815 (16)	0.06628 (6)	0.0309 (3)
H4A	0.543928	0.260389	0.042478	0.037*
H4B	0.659959	0.373215	0.033868	0.037*
C5	0.71019 (14)	0.22598 (16)	0.11530 (7)	0.0338 (3)
H5A	0.747324	0.143084	0.091575	0.041*
H5B	0.663878	0.171422	0.144764	0.041*
C6	0.81856 (13)	0.32806 (17)	0.15593 (7)	0.0326 (3)
H6A	0.876451	0.259820	0.188574	0.039*
H6B	0.869730	0.374891	0.126927	0.039*
C7	0.76473 (12)	0.46177 (16)	0.19109 (6)	0.0281 (3)
H7A	0.721941	0.415001	0.223745	0.034*
H7B	0.836226	0.530316	0.214656	0.034*
C8	0.71074 (12)	0.79636 (15)	0.22593 (6)	0.0237 (2)
C9	0.67533 (13)	0.74102 (16)	0.28152 (6)	0.0291 (3)
H9	0.610411	0.661492	0.277178	0.035*
C10	0.73298 (13)	0.79965 (16)	0.34346 (6)	0.0290 (3)
H10	0.707519	0.760341	0.380925	0.035*
C11	0.82765 (12)	0.91559 (16)	0.35015 (6)	0.0271 (3)
C12	0.86493 (12)	0.97195 (16)	0.29507 (6)	0.0278 (3)
H12	0.930032	1.051250	0.299498	0.033*
C13	0.80682 (12)	0.91209 (15)	0.23369 (6)	0.0254 (3)
H13	0.833006	0.950699	0.196314	0.030*
C14	0.84186 (16)	0.9367 (3)	0.46447 (7)	0.0508 (4)
H14A	0.749170	0.958339	0.455212	0.076*
H14B	0.885966	0.999238	0.502593	0.076*
H14C	0.857201	0.822679	0.473620	0.076*
C15	0.50846 (12)	0.79871 (15)	0.13383 (6)	0.0240 (2)
C16	0.40710 (13)	0.74695 (17)	0.16004 (6)	0.0299 (3)
H16	0.423268	0.668698	0.193729	0.036*
C17	0.28309 (13)	0.80669 (17)	0.13825 (7)	0.0304 (3)
H17	0.215689	0.769833	0.157030	0.036*
C18	0.25829 (12)	0.92048 (16)	0.08888 (6)	0.0280 (3)
C19	0.35817 (13)	0.97422 (16)	0.06218 (6)	0.0282 (3)
H19	0.341838	1.052592	0.028545	0.034*
C20	0.48113 (12)	0.91381 (15)	0.08450 (6)	0.0252 (3)
H20	0.548440	0.951492	0.065830	0.030*
C21	0.03735 (15)	0.9424 (3)	0.09253 (9)	0.0544 (5)
H21A	0.022375	0.827032	0.087960	0.082*
H21B	−0.041139	0.999579	0.070816	0.082*
H21C	0.060354	0.970774	0.139073	0.082*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.02968 (17)	0.02958 (18)	0.02390 (16)	−0.00255 (12)	0.01074 (12)	−0.00057 (12)
O11	0.0338 (5)	0.0515 (6)	0.0216 (5)	−0.0032 (4)	0.0026 (4)	−0.0073 (4)
O18	0.0261 (5)	0.0487 (6)	0.0380 (5)	0.0047 (4)	0.0040 (4)	0.0065 (5)
C1	0.0263 (6)	0.0266 (6)	0.0198 (6)	−0.0030 (5)	0.0079 (5)	0.0005 (5)
C2	0.0254 (6)	0.0268 (6)	0.0217 (6)	−0.0016 (5)	0.0062 (5)	0.0008 (5)
C3	0.0268 (6)	0.0283 (6)	0.0253 (6)	−0.0036 (5)	0.0025 (5)	−0.0001 (5)
C4	0.0341 (7)	0.0284 (7)	0.0279 (6)	−0.0030 (5)	0.0026 (5)	−0.0034 (5)
C5	0.0364 (7)	0.0245 (6)	0.0377 (7)	−0.0001 (5)	0.0029 (6)	−0.0026 (6)
C6	0.0310 (7)	0.0290 (7)	0.0347 (7)	0.0023 (5)	0.0016 (5)	−0.0006 (6)
C7	0.0276 (6)	0.0293 (7)	0.0252 (6)	−0.0009 (5)	0.0014 (5)	0.0005 (5)
C8	0.0260 (6)	0.0244 (6)	0.0209 (6)	0.0011 (5)	0.0058 (5)	−0.0010 (5)
C9	0.0313 (7)	0.0310 (7)	0.0258 (6)	−0.0037 (5)	0.0084 (5)	−0.0007 (5)
C10	0.0321 (7)	0.0347 (7)	0.0212 (6)	0.0015 (5)	0.0085 (5)	0.0014 (5)
C11	0.0262 (6)	0.0325 (7)	0.0206 (6)	0.0058 (5)	0.0018 (5)	−0.0030 (5)
C12	0.0250 (6)	0.0294 (7)	0.0277 (6)	−0.0015 (5)	0.0034 (5)	−0.0017 (5)
C13	0.0271 (6)	0.0266 (6)	0.0226 (6)	0.0003 (5)	0.0063 (5)	0.0018 (5)
C14	0.0411 (8)	0.0889 (14)	0.0228 (7)	−0.0074 (9)	0.0079 (6)	−0.0129 (8)
C15	0.0262 (6)	0.0247 (6)	0.0211 (6)	−0.0021 (5)	0.0058 (5)	−0.0024 (5)
C16	0.0317 (7)	0.0315 (7)	0.0277 (6)	−0.0005 (5)	0.0096 (5)	0.0059 (5)
C17	0.0276 (6)	0.0344 (7)	0.0308 (7)	−0.0034 (5)	0.0101 (5)	0.0014 (5)
C18	0.0258 (6)	0.0299 (7)	0.0267 (6)	0.0008 (5)	0.0029 (5)	−0.0033 (5)
C19	0.0327 (7)	0.0286 (7)	0.0228 (6)	0.0008 (5)	0.0055 (5)	0.0021 (5)
C20	0.0288 (6)	0.0252 (6)	0.0227 (6)	−0.0033 (5)	0.0080 (5)	−0.0017 (5)
C21	0.0283 (7)	0.0824 (13)	0.0529 (10)	0.0085 (8)	0.0107 (7)	0.0151 (9)

Geometric parameters (Å, º) top

S1—C1	1.8381 (12)	C8—C13	1.3927 (17)
S1—C2	1.8493 (12)	C9—C10	1.3921 (18)
O11—C11	1.3723 (15)	C9—H9	0.9500
O11—C14	1.4296 (18)	C10—C11	1.3846 (19)
O18—C18	1.3681 (16)	C10—H10	0.9500
O18—C21	1.4269 (18)	C11—C12	1.3916 (18)
C1—C2	1.5041 (18)	C12—C13	1.3871 (17)
C1—C15	1.5151 (17)	C12—H12	0.9500
C1—C8	1.5152 (16)	C13—H13	0.9500
C2—C7	1.5156 (17)	C14—H14A	0.9800
C2—C3	1.5160 (17)	C14—H14B	0.9800
C3—C4	1.5300 (19)	C14—H14C	0.9800
C3—H3A	0.9900	C15—C16	1.3939 (18)
C3—H3B	0.9900	C15—C20	1.3949 (17)
C4—C5	1.5241 (19)	C16—C17	1.3892 (19)
C4—H4A	0.9900	C16—H16	0.9500
C4—H4B	0.9900	C17—C18	1.3872 (19)
C5—C6	1.5280 (19)	C17—H17	0.9500
C5—H5A	0.9900	C18—C19	1.3914 (18)
C5—H5B	0.9900	C19—C20	1.3826 (18)
C6—C7	1.5258 (19)	C19—H19	0.9500
C6—H6A	0.9900	C20—H20	0.9500
C6—H6B	0.9900	C21—H21A	0.9800
C7—H7A	0.9900	C21—H21B	0.9800
C7—H7B	0.9900	C21—H21C	0.9800
C8—C9	1.3889 (17)

C1—S1—C2	48.14 (6)	C13—C8—C1	122.32 (11)
C11—O11—C14	116.09 (11)	C8—C9—C10	121.37 (12)
C18—O18—C21	117.23 (12)	C8—C9—H9	119.3
C2—C1—C15	118.47 (10)	C10—C9—H9	119.3
C2—C1—C8	118.20 (10)	C11—C10—C9	119.63 (12)
C15—C1—C8	113.92 (10)	C11—C10—H10	120.2
C2—C1—S1	66.32 (7)	C9—C10—H10	120.2
C15—C1—S1	115.75 (8)	O11—C11—C10	123.99 (12)
C8—C1—S1	116.01 (8)	O11—C11—C12	116.16 (12)
C1—C2—C7	120.28 (10)	C10—C11—C12	119.85 (11)
C1—C2—C3	119.47 (10)	C13—C12—C11	119.86 (12)
C7—C2—C3	113.01 (11)	C13—C12—H12	120.1
C1—C2—S1	65.54 (7)	C11—C12—H12	120.1
C7—C2—S1	114.82 (9)	C12—C13—C8	121.12 (11)
C3—C2—S1	115.18 (8)	C12—C13—H13	119.4
C2—C3—C4	111.37 (10)	C8—C13—H13	119.4
C2—C3—H3A	109.4	O11—C14—H14A	109.5
C4—C3—H3A	109.4	O11—C14—H14B	109.5
C2—C3—H3B	109.4	H14A—C14—H14B	109.5
C4—C3—H3B	109.4	O11—C14—H14C	109.5
H3A—C3—H3B	108.0	H14A—C14—H14C	109.5
C5—C4—C3	111.32 (11)	H14B—C14—H14C	109.5
C5—C4—H4A	109.4	C16—C15—C20	117.50 (12)
C3—C4—H4A	109.4	C16—C15—C1	120.33 (11)
C5—C4—H4B	109.4	C20—C15—C1	122.17 (11)
C3—C4—H4B	109.4	C17—C16—C15	121.79 (12)
H4A—C4—H4B	108.0	C17—C16—H16	119.1
C4—C5—C6	111.01 (11)	C15—C16—H16	119.1
C4—C5—H5A	109.4	C18—C17—C16	119.59 (12)
C6—C5—H5A	109.4	C18—C17—H17	120.2
C4—C5—H5B	109.4	C16—C17—H17	120.2
C6—C5—H5B	109.4	O18—C18—C17	124.65 (12)
H5A—C5—H5B	108.0	O18—C18—C19	115.79 (12)
C7—C6—C5	111.01 (11)	C17—C18—C19	119.56 (12)
C7—C6—H6A	109.4	C20—C19—C18	120.15 (12)
C5—C6—H6A	109.4	C20—C19—H19	119.9
C7—C6—H6B	109.4	C18—C19—H19	119.9
C5—C6—H6B	109.4	C19—C20—C15	121.41 (12)
H6A—C6—H6B	108.0	C19—C20—H20	119.3
C2—C7—C6	110.89 (10)	C15—C20—H20	119.3
C2—C7—H7A	109.5	O18—C21—H21A	109.5
C6—C7—H7A	109.5	O18—C21—H21B	109.5
C2—C7—H7B	109.5	H21A—C21—H21B	109.5
C6—C7—H7B	109.5	O18—C21—H21C	109.5
H7A—C7—H7B	108.1	H21A—C21—H21C	109.5
C9—C8—C13	118.17 (11)	H21B—C21—H21C	109.5
C9—C8—C1	119.50 (11)

C2—S1—C1—C15	−111.49 (11)	C1—C8—C9—C10	−178.37 (12)
C2—S1—C1—C8	111.11 (12)	C8—C9—C10—C11	0.0 (2)
C15—C1—C2—C7	−146.87 (11)	C14—O11—C11—C10	−7.65 (19)
C8—C1—C2—C7	−2.38 (16)	C14—O11—C11—C12	172.89 (13)
S1—C1—C2—C7	105.57 (11)	C9—C10—C11—O11	−179.80 (12)
C15—C1—C2—C3	1.31 (16)	C9—C10—C11—C12	−0.3 (2)
C8—C1—C2—C3	145.80 (11)	O11—C11—C12—C13	179.68 (11)
S1—C1—C2—C3	−106.25 (11)	C10—C11—C12—C13	0.19 (19)
C15—C1—C2—S1	107.56 (10)	C11—C12—C13—C8	0.31 (19)
C8—C1—C2—S1	−107.95 (10)	C9—C8—C13—C12	−0.63 (19)
C1—S1—C2—C7	−113.57 (11)	C1—C8—C13—C12	178.18 (12)
C1—S1—C2—C3	112.54 (12)	C2—C1—C15—C16	71.48 (15)
C1—C2—C3—C4	156.42 (11)	C8—C1—C15—C16	−74.46 (15)
C7—C2—C3—C4	−53.23 (14)	S1—C1—C15—C16	147.25 (10)
S1—C2—C3—C4	81.48 (12)	C2—C1—C15—C20	−109.30 (13)
C2—C3—C4—C5	53.57 (15)	C8—C1—C15—C20	104.76 (13)
C3—C4—C5—C6	−55.72 (16)	S1—C1—C15—C20	−33.53 (15)
C4—C5—C6—C7	56.76 (16)	C20—C15—C16—C17	0.06 (19)
C1—C2—C7—C6	−155.75 (11)	C1—C15—C16—C17	179.31 (12)
C3—C2—C7—C6	54.17 (14)	C15—C16—C17—C18	0.3 (2)
S1—C2—C7—C6	−80.72 (12)	C21—O18—C18—C17	4.9 (2)
C5—C6—C7—C2	−55.42 (15)	C21—O18—C18—C19	−175.48 (14)
C2—C1—C8—C9	−70.72 (15)	C16—C17—C18—O18	179.08 (12)
C15—C1—C8—C9	75.32 (15)	C16—C17—C18—C19	−0.5 (2)
S1—C1—C8—C9	−146.51 (10)	O18—C18—C19—C20	−179.23 (11)
C2—C1—C8—C13	110.48 (13)	C17—C18—C19—C20	0.37 (19)
C15—C1—C8—C13	−103.48 (13)	C18—C19—C20—C15	−0.03 (19)
S1—C1—C8—C13	34.69 (16)	C16—C15—C20—C19	−0.18 (18)
C13—C8—C9—C10	0.47 (19)	C1—C15—C20—C19	−179.42 (11)

1-[Cyclohexylidene(4-methoxyphenyl)methyl]-4-methoxybenzene (11) top

Crystal data top

C₂₁H₂₄O₂	D_x = 1.209 Mg m⁻³
M_r = 308.40	Melting point: 382 K
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 12.3664 (2) Å	Cell parameters from 4255 reflections
b = 5.3819 (1) Å	θ = 2.0–27.5°
c = 25.5086 (5) Å	µ = 0.08 mm⁻¹
β = 93.4911 (10)°	T = 160 K
V = 1694.57 (5) Å³	Prism, colorless
Z = 4	0.25 × 0.15 × 0.08 mm
F(000) = 664

Data collection top

Nonius KappaCCD area-detector diffractometer	2994 independent reflections
Radiation source: Nonius FR590 sealed tube generator	2356 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.079
Detector resolution: 9 pixels mm^-1	θ_max = 25.0°, θ_min = 3.2°
φ and ω scans with κ offsets	h = −14→14
Absorption correction: multi-scan (Blessing, 1995)	k = −6→6
T_min = 0.809, T_max = 0.999	l = −30→29
30267 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.057	H-atom parameters constrained
wR(F²) = 0.151	w = 1/[σ²(F_o²) + (0.0695P)² + 1.1639P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
2992 reflections	Δρ_max = 0.44 e Å⁻³
210 parameters	Δρ_min = −0.21 e Å⁻³
0 restraints

Special details top

Experimental. Data collection and full structure determination done by Prof. Anthony Linden: [email protected]

Solvent used: CH2Cl2 / n-hexane Cooling Device: Oxford Cryosystems Cryostream 700 Crystal mount: on a glass fibre Mosaicity (deg.): 0.716 (1) Frames collected: 798 Seconds exposure per frame: 50 Degrees rotation per frame: 1.0 Crystal-detector distance (mm): 35.0 Client: Daniel Egli Sample code: 29 (HG0117)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O11	0.90829 (12)	0.2799 (3)	0.31845 (5)	0.0376 (4)
O18	0.92248 (12)	0.3067 (3)	−0.04335 (5)	0.0364 (4)
C1	0.64944 (16)	0.2691 (4)	0.12690 (8)	0.0278 (5)
C2	0.54097 (16)	0.2577 (4)	0.12404 (8)	0.0309 (5)
C3	0.47346 (17)	0.2191 (5)	0.07335 (8)	0.0368 (5)
H3A	0.521496	0.205427	0.043817	0.044*
H3B	0.425127	0.363738	0.066663	0.044*
C4	0.40570 (19)	−0.0168 (5)	0.07653 (10)	0.0431 (6)
H4A	0.454433	−0.162793	0.079172	0.052*
H4B	0.358589	−0.033957	0.043936	0.052*
C5	0.33549 (19)	−0.0130 (5)	0.12374 (10)	0.0482 (7)
H5A	0.296986	−0.173613	0.125959	0.058*
H5B	0.280496	0.120017	0.118972	0.058*
C6	0.40395 (19)	0.0315 (5)	0.17474 (9)	0.0418 (6)
H6A	0.355901	0.047537	0.204216	0.050*
H6B	0.452314	−0.112584	0.181998	0.050*
C7	0.47193 (17)	0.2670 (4)	0.17102 (9)	0.0358 (5)
H7A	0.423453	0.413335	0.167978	0.043*
H7B	0.519283	0.285675	0.203492	0.043*
C8	0.71732 (15)	0.2738 (4)	0.17757 (7)	0.0262 (5)
C9	0.79499 (17)	0.4594 (4)	0.18697 (8)	0.0307 (5)
H9	0.803376	0.582818	0.160904	0.037*
C10	0.86048 (17)	0.4697 (4)	0.23322 (8)	0.0303 (5)
H10	0.912170	0.599029	0.238816	0.036*
C11	0.84906 (16)	0.2876 (4)	0.27108 (7)	0.0283 (5)
C12	0.77454 (16)	0.0977 (4)	0.26199 (8)	0.0308 (5)
H12	0.768087	−0.028892	0.287563	0.037*
C13	0.70958 (16)	0.0915 (4)	0.21598 (8)	0.0302 (5)
H13	0.658690	−0.039548	0.210418	0.036*
C14	0.97417 (19)	0.4906 (4)	0.33229 (9)	0.0394 (6)
H14A	1.035188	0.497781	0.309560	0.059*
H14B	1.001698	0.476234	0.369009	0.059*
H14C	0.930815	0.642385	0.327793	0.059*
C15	0.71438 (15)	0.2783 (4)	0.07937 (7)	0.0268 (5)
C16	0.70617 (16)	0.4752 (4)	0.04383 (8)	0.0282 (5)
H16	0.654014	0.601918	0.048273	0.034*
C17	0.77306 (16)	0.4895 (4)	0.00194 (7)	0.0272 (5)
H17	0.766256	0.624770	−0.021964	0.033*
C18	0.84965 (15)	0.3058 (4)	−0.00477 (7)	0.0280 (5)
C19	0.85706 (16)	0.1052 (4)	0.02960 (8)	0.0292 (5)
H19	0.907458	−0.024442	0.024417	0.035*
C20	0.79125 (16)	0.0947 (4)	0.07113 (8)	0.0286 (5)
H20	0.798320	−0.041196	0.094858	0.034*
C21	0.92289 (19)	0.5200 (4)	−0.07642 (8)	0.0359 (5)
H21A	0.855084	0.526514	−0.098361	0.054*
H21B	0.984219	0.510006	−0.098917	0.054*
H21C	0.929641	0.670099	−0.054729	0.054*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O11	0.0360 (8)	0.0474 (10)	0.0286 (8)	−0.0034 (7)	−0.0033 (6)	0.0028 (7)
O18	0.0365 (8)	0.0419 (9)	0.0316 (8)	0.0035 (7)	0.0097 (6)	0.0034 (7)
C1	0.0286 (11)	0.0254 (11)	0.0295 (10)	−0.0004 (9)	0.0029 (8)	−0.0001 (8)
C2	0.0276 (11)	0.0302 (12)	0.0349 (11)	0.0004 (9)	0.0015 (9)	0.0013 (9)
C3	0.0269 (11)	0.0446 (14)	0.0386 (12)	−0.0028 (10)	−0.0013 (9)	0.0006 (10)
C4	0.0311 (12)	0.0480 (15)	0.0492 (14)	−0.0067 (11)	−0.0052 (10)	−0.0044 (11)
C5	0.0296 (12)	0.0532 (16)	0.0617 (16)	−0.0122 (11)	0.0023 (11)	0.0034 (13)
C6	0.0301 (12)	0.0476 (15)	0.0483 (14)	−0.0059 (11)	0.0080 (10)	0.0050 (11)
C7	0.0267 (11)	0.0410 (13)	0.0399 (12)	0.0024 (10)	0.0043 (9)	−0.0001 (10)
C8	0.0238 (10)	0.0275 (11)	0.0277 (10)	0.0017 (9)	0.0047 (8)	−0.0016 (8)
C9	0.0305 (11)	0.0337 (12)	0.0278 (10)	−0.0027 (9)	0.0023 (8)	0.0038 (9)
C10	0.0270 (11)	0.0337 (12)	0.0303 (11)	−0.0050 (9)	0.0018 (8)	−0.0020 (9)
C11	0.0243 (10)	0.0365 (12)	0.0243 (10)	0.0044 (9)	0.0023 (8)	−0.0025 (9)
C12	0.0304 (11)	0.0347 (12)	0.0279 (10)	0.0004 (10)	0.0059 (8)	0.0053 (9)
C13	0.0266 (10)	0.0320 (12)	0.0325 (11)	−0.0031 (9)	0.0054 (8)	−0.0016 (9)
C14	0.0372 (13)	0.0482 (15)	0.0318 (11)	−0.0032 (11)	−0.0059 (10)	−0.0058 (10)
C15	0.0223 (10)	0.0300 (11)	0.0278 (10)	−0.0030 (9)	−0.0019 (8)	−0.0020 (9)
C16	0.0225 (10)	0.0300 (12)	0.0318 (11)	0.0012 (9)	0.0004 (8)	0.0000 (9)
C17	0.0266 (10)	0.0291 (11)	0.0254 (10)	−0.0010 (9)	−0.0031 (8)	0.0052 (8)
C18	0.0228 (10)	0.0361 (12)	0.0249 (10)	−0.0032 (9)	0.0002 (8)	−0.0033 (9)
C19	0.0276 (11)	0.0287 (11)	0.0312 (11)	0.0031 (9)	0.0012 (8)	−0.0023 (9)
C20	0.0279 (11)	0.0284 (11)	0.0289 (10)	−0.0013 (9)	−0.0035 (8)	0.0023 (9)
C21	0.0401 (13)	0.0419 (14)	0.0263 (11)	−0.0034 (10)	0.0062 (9)	0.0023 (10)

Geometric parameters (Å, º) top

O11—C11	1.375 (2)	C9—C10	1.391 (3)
O11—C14	1.428 (3)	C9—H9	0.9500
O18—C18	1.374 (2)	C10—C11	1.389 (3)
O18—C21	1.425 (3)	C10—H10	0.9500
C1—C2	1.340 (3)	C11—C12	1.386 (3)
C1—C15	1.495 (3)	C12—C13	1.382 (3)
C1—C8	1.498 (3)	C12—H12	0.9500
C2—C3	1.510 (3)	C13—H13	0.9500
C2—C7	1.514 (3)	C14—H14A	0.9800
C3—C4	1.526 (3)	C14—H14B	0.9800
C3—H3A	0.9900	C14—H14C	0.9800
C3—H3B	0.9900	C15—C16	1.395 (3)
C4—C5	1.527 (3)	C15—C20	1.396 (3)
C4—H4A	0.9900	C16—C17	1.393 (3)
C4—H4B	0.9900	C16—H16	0.9500
C5—C6	1.527 (3)	C17—C18	1.387 (3)
C5—H5A	0.9900	C17—H17	0.9500
C5—H5B	0.9900	C18—C19	1.390 (3)
C6—C7	1.527 (3)	C19—C20	1.376 (3)
C6—H6A	0.9900	C19—H19	0.9500
C6—H6B	0.9900	C20—H20	0.9500
C7—H7A	0.9900	C21—H21A	0.9800
C7—H7B	0.9900	C21—H21B	0.9800
C8—C13	1.394 (3)	C21—H21C	0.9800
C8—C9	1.396 (3)

C11—O11—C14	117.29 (16)	C8—C9—H9	118.9
C18—O18—C21	116.93 (16)	C11—C10—C9	118.89 (19)
C2—C1—C15	122.85 (18)	C11—C10—H10	120.6
C2—C1—C8	123.65 (18)	C9—C10—H10	120.6
C15—C1—C8	113.49 (16)	O11—C11—C12	115.97 (18)
C1—C2—C3	123.51 (19)	O11—C11—C10	124.13 (19)
C1—C2—C7	124.49 (19)	C12—C11—C10	119.90 (18)
C3—C2—C7	111.92 (17)	C13—C12—C11	120.42 (19)
C2—C3—C4	110.22 (19)	C13—C12—H12	119.8
C2—C3—H3A	109.6	C11—C12—H12	119.8
C4—C3—H3A	109.6	C12—C13—C8	121.2 (2)
C2—C3—H3B	109.6	C12—C13—H13	119.4
C4—C3—H3B	109.6	C8—C13—H13	119.4
H3A—C3—H3B	108.1	O11—C14—H14A	109.5
C3—C4—C5	111.8 (2)	O11—C14—H14B	109.5
C3—C4—H4A	109.3	H14A—C14—H14B	109.5
C5—C4—H4A	109.3	O11—C14—H14C	109.5
C3—C4—H4B	109.3	H14A—C14—H14C	109.5
C5—C4—H4B	109.3	H14B—C14—H14C	109.5
H4A—C4—H4B	107.9	C16—C15—C20	117.61 (18)
C4—C5—C6	111.20 (18)	C16—C15—C1	122.07 (18)
C4—C5—H5A	109.4	C20—C15—C1	120.20 (18)
C6—C5—H5A	109.4	C17—C16—C15	121.17 (19)
C4—C5—H5B	109.4	C17—C16—H16	119.4
C6—C5—H5B	109.4	C15—C16—H16	119.4
H5A—C5—H5B	108.0	C18—C17—C16	119.82 (18)
C7—C6—C5	110.86 (19)	C18—C17—H17	120.1
C7—C6—H6A	109.5	C16—C17—H17	120.1
C5—C6—H6A	109.5	O18—C18—C17	124.63 (19)
C7—C6—H6B	109.5	O18—C18—C19	115.69 (18)
C5—C6—H6B	109.5	C17—C18—C19	119.67 (18)
H6A—C6—H6B	108.1	C20—C19—C18	119.87 (19)
C2—C7—C6	111.16 (19)	C20—C19—H19	120.1
C2—C7—H7A	109.4	C18—C19—H19	120.1
C6—C7—H7A	109.4	C19—C20—C15	121.82 (19)
C2—C7—H7B	109.4	C19—C20—H20	119.1
C6—C7—H7B	109.4	C15—C20—H20	119.1
H7A—C7—H7B	108.0	O18—C21—H21A	109.5
C13—C8—C9	117.31 (18)	O18—C21—H21B	109.5
C13—C8—C1	122.39 (18)	H21A—C21—H21B	109.5
C9—C8—C1	120.25 (18)	O18—C21—H21C	109.5
C10—C9—C8	122.21 (19)	H21A—C21—H21C	109.5
C10—C9—H9	118.9	H21B—C21—H21C	109.5

C15—C1—C2—C3	8.3 (3)	C9—C10—C11—C12	1.1 (3)
C8—C1—C2—C3	−171.7 (2)	O11—C11—C12—C13	178.76 (18)
C15—C1—C2—C7	−175.3 (2)	C10—C11—C12—C13	−1.5 (3)
C8—C1—C2—C7	4.7 (3)	C11—C12—C13—C8	0.3 (3)
C1—C2—C3—C4	120.3 (2)	C9—C8—C13—C12	1.4 (3)
C7—C2—C3—C4	−56.4 (2)	C1—C8—C13—C12	178.82 (18)
C2—C3—C4—C5	55.4 (2)	C2—C1—C15—C16	63.1 (3)
C3—C4—C5—C6	−54.9 (3)	C8—C1—C15—C16	−116.9 (2)
C4—C5—C6—C7	54.3 (3)	C2—C1—C15—C20	−121.1 (2)
C1—C2—C7—C6	−119.9 (2)	C8—C1—C15—C20	58.9 (2)
C3—C2—C7—C6	56.8 (2)	C20—C15—C16—C17	−0.7 (3)
C5—C6—C7—C2	−55.2 (2)	C1—C15—C16—C17	175.20 (18)
C2—C1—C8—C13	55.1 (3)	C15—C16—C17—C18	−0.2 (3)
C15—C1—C8—C13	−124.9 (2)	C21—O18—C18—C17	4.1 (3)
C2—C1—C8—C9	−127.6 (2)	C21—O18—C18—C19	−174.90 (17)
C15—C1—C8—C9	52.4 (3)	C16—C17—C18—O18	−177.26 (18)
C13—C8—C9—C10	−1.9 (3)	C16—C17—C18—C19	1.7 (3)
C1—C8—C9—C10	−179.38 (18)	O18—C18—C19—C20	176.66 (17)
C8—C9—C10—C11	0.7 (3)	C17—C18—C19—C20	−2.4 (3)
C14—O11—C11—C12	−171.17 (18)	C18—C19—C20—C15	1.6 (3)
C14—O11—C11—C10	9.1 (3)	C16—C15—C20—C19	0.0 (3)
C9—C10—C11—O11	−179.28 (18)	C1—C15—C20—C19	−175.98 (18)

3-[Bis(4-methoxyphenyl)methylidene]-5-phenyl-3H-1,2-dithiole (13) top

Crystal data top

C₂₄H₂₀O₂S₂	F(000) = 848
M_r = 404.52	D_x = 1.342 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 15.2746 (2) Å	Cell parameters from 89387 reflections
b = 6.6094 (1) Å	θ = 2.0–27.5°
c = 19.8754 (3) Å	µ = 0.28 mm⁻¹
β = 93.5489 (9)°	T = 160 K
V = 2002.69 (5) Å³	Prism, red
Z = 4	0.30 × 0.25 × 0.15 mm

Data collection top

Nonius KappaCCD area-detector diffractometer	4597 independent reflections
Radiation source: Nonius FR590 sealed tube generator	3564 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.060
Detector resolution: 9 pixels mm^-1	θ_max = 27.5°, θ_min = 2.1°
φ and ω scans with κ offsets	h = −19→19
Absorption correction: multi-scan (Blessing, 1995)	k = −8→8
T_min = 0.863, T_max = 0.961	l = −25→25
45139 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.042	H-atom parameters constrained
wR(F²) = 0.112	w = 1/[σ²(F_o²) + (0.0515P)² + 0.996P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max = 0.001
4597 reflections	Δρ_max = 0.29 e Å⁻³
255 parameters	Δρ_min = −0.34 e Å⁻³
0 restraints

Special details top

Experimental. Data collection and full structure determination done by Prof. Anthony Linden: [email protected]

Solvent used: n-hexane / EtOAc Cooling Device: Oxford Cryosystems Cryostream 700 Crystal mount: on a glass fibre Mosaicity (deg.): 0.736 (1) Frames collected: 792 Seconds exposure per frame: 14 Degrees rotation per frame: 0.8 Crystal-detector distance (mm): 30.0 Client: Daniel Egli Sample code: 546-2 (HG0565)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	0.81169 (3)	0.02969 (7)	0.18723 (2)	0.03566 (14)
S2	0.89382 (3)	−0.21239 (7)	0.21415 (2)	0.03574 (14)
O16	0.67096 (9)	−0.1967 (2)	−0.21293 (6)	0.0389 (3)
O23	0.51306 (9)	0.6949 (2)	0.13085 (7)	0.0441 (3)
C3	0.90450 (11)	−0.2908 (3)	0.13060 (8)	0.0279 (4)
C4	0.85607 (11)	−0.1924 (3)	0.08229 (8)	0.0279 (4)
H4	0.860230	−0.228548	0.036344	0.033*
C5	0.79763 (11)	−0.0314 (3)	0.10002 (8)	0.0279 (4)
C6	0.73775 (11)	0.0630 (3)	0.05719 (8)	0.0277 (4)
C7	0.96095 (11)	−0.4669 (3)	0.11990 (8)	0.0283 (4)
C8	1.03456 (12)	−0.5078 (3)	0.16258 (9)	0.0359 (4)
H8	1.049269	−0.420049	0.199431	0.043*
C9	1.08669 (14)	−0.6753 (3)	0.15186 (10)	0.0441 (5)
H9	1.137079	−0.700957	0.181060	0.053*
C10	1.06553 (14)	−0.8044 (3)	0.09904 (11)	0.0449 (5)
H10	1.100868	−0.919655	0.091785	0.054*
C11	0.99230 (14)	−0.7647 (3)	0.05653 (10)	0.0407 (5)
H11	0.977848	−0.852939	0.019764	0.049*
C12	0.94032 (12)	−0.5997 (3)	0.06684 (9)	0.0339 (4)
H12	0.889852	−0.575731	0.037556	0.041*
C13	0.72244 (11)	−0.0118 (3)	−0.01340 (8)	0.0281 (4)
C14	0.70204 (11)	−0.2129 (3)	−0.02748 (8)	0.0297 (4)
H14	0.699560	−0.306181	0.008715	0.036*
C15	0.68516 (11)	−0.2810 (3)	−0.09324 (8)	0.0297 (4)
H15	0.671967	−0.419523	−0.101704	0.036*
C16	0.68770 (12)	−0.1455 (3)	−0.14638 (8)	0.0304 (4)
C17	0.70759 (13)	0.0561 (3)	−0.13345 (9)	0.0354 (4)
H17	0.709595	0.149219	−0.169745	0.042*
C18	0.72452 (12)	0.1222 (3)	−0.06784 (9)	0.0336 (4)
H18	0.737784	0.260725	−0.059609	0.040*
C19	0.64583 (15)	−0.4012 (3)	−0.22711 (10)	0.0436 (5)
H19A	0.694770	−0.491668	−0.213957	0.065*
H19B	0.630435	−0.416033	−0.275459	0.065*
H19C	0.595035	−0.436246	−0.201640	0.065*
C20	0.68241 (11)	0.2331 (3)	0.07760 (8)	0.0283 (4)
C21	0.59439 (12)	0.2448 (3)	0.05283 (9)	0.0360 (4)
H21	0.571730	0.145202	0.022003	0.043*
C22	0.54040 (12)	0.3977 (3)	0.07233 (10)	0.0386 (4)
H22	0.480747	0.400656	0.055705	0.046*
C23	0.57236 (12)	0.5480 (3)	0.11616 (9)	0.0326 (4)
C24	0.65936 (12)	0.5441 (3)	0.14044 (8)	0.0294 (4)
H24	0.682115	0.647347	0.169811	0.035*
C25	0.71305 (11)	0.3863 (3)	0.12117 (8)	0.0274 (4)
H25	0.772490	0.383138	0.138299	0.033*
C26	0.54322 (15)	0.8527 (3)	0.17532 (11)	0.0490 (5)
H26A	0.561511	0.795153	0.219408	0.074*
H26B	0.495745	0.950193	0.180498	0.074*
H26C	0.593130	0.921443	0.156637	0.074*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0446 (3)	0.0360 (3)	0.0255 (2)	0.0130 (2)	−0.00476 (18)	−0.00565 (18)
S2	0.0447 (3)	0.0368 (3)	0.0250 (2)	0.0121 (2)	−0.00345 (18)	−0.00208 (18)
O16	0.0573 (9)	0.0346 (7)	0.0240 (6)	0.0020 (6)	−0.0041 (6)	−0.0017 (5)
O23	0.0405 (8)	0.0475 (8)	0.0444 (8)	0.0173 (6)	0.0041 (6)	−0.0042 (6)
C3	0.0298 (9)	0.0265 (9)	0.0275 (8)	−0.0008 (7)	0.0016 (7)	−0.0023 (7)
C4	0.0298 (9)	0.0287 (9)	0.0250 (8)	0.0004 (7)	0.0006 (6)	−0.0022 (7)
C5	0.0307 (9)	0.0277 (9)	0.0250 (8)	0.0008 (7)	0.0010 (7)	−0.0023 (7)
C6	0.0296 (9)	0.0287 (9)	0.0245 (8)	0.0013 (7)	0.0002 (6)	−0.0019 (7)
C7	0.0305 (9)	0.0264 (8)	0.0283 (8)	0.0012 (7)	0.0043 (7)	0.0028 (7)
C8	0.0366 (10)	0.0384 (10)	0.0326 (9)	0.0062 (8)	0.0002 (7)	0.0017 (8)
C9	0.0391 (11)	0.0498 (12)	0.0435 (11)	0.0153 (9)	0.0039 (9)	0.0108 (9)
C10	0.0504 (12)	0.0377 (11)	0.0478 (12)	0.0175 (9)	0.0141 (9)	0.0042 (9)
C11	0.0475 (12)	0.0343 (10)	0.0411 (11)	0.0045 (9)	0.0090 (9)	−0.0053 (8)
C12	0.0355 (10)	0.0317 (10)	0.0346 (9)	0.0014 (8)	0.0022 (7)	−0.0025 (7)
C13	0.0288 (9)	0.0303 (9)	0.0249 (8)	0.0045 (7)	−0.0011 (6)	0.0005 (7)
C14	0.0322 (9)	0.0308 (9)	0.0258 (8)	0.0007 (7)	−0.0007 (7)	0.0034 (7)
C15	0.0328 (9)	0.0266 (9)	0.0294 (8)	0.0001 (7)	−0.0003 (7)	0.0000 (7)
C16	0.0336 (9)	0.0336 (9)	0.0236 (8)	0.0062 (8)	−0.0015 (7)	−0.0011 (7)
C17	0.0476 (11)	0.0299 (9)	0.0283 (9)	0.0060 (8)	0.0000 (8)	0.0050 (7)
C18	0.0453 (11)	0.0250 (9)	0.0300 (9)	0.0048 (8)	−0.0017 (7)	0.0006 (7)
C19	0.0607 (13)	0.0381 (11)	0.0311 (9)	−0.0001 (10)	−0.0041 (9)	−0.0069 (8)
C20	0.0314 (9)	0.0297 (9)	0.0237 (8)	0.0019 (7)	0.0004 (6)	0.0025 (7)
C21	0.0326 (10)	0.0407 (11)	0.0339 (9)	0.0027 (8)	−0.0036 (7)	−0.0048 (8)
C22	0.0271 (9)	0.0469 (12)	0.0412 (10)	0.0073 (8)	−0.0020 (8)	−0.0016 (9)
C23	0.0340 (9)	0.0353 (10)	0.0290 (9)	0.0113 (8)	0.0069 (7)	0.0039 (7)
C24	0.0350 (9)	0.0291 (9)	0.0241 (8)	0.0018 (7)	0.0028 (7)	0.0026 (7)
C25	0.0276 (8)	0.0285 (9)	0.0262 (8)	0.0023 (7)	0.0018 (6)	0.0038 (7)
C26	0.0588 (14)	0.0428 (12)	0.0458 (12)	0.0206 (10)	0.0057 (10)	−0.0052 (9)

Geometric parameters (Å, º) top

S1—C5	1.7797 (17)	C13—C18	1.400 (2)
S1—S2	2.0826 (6)	C14—C15	1.392 (2)
S2—C3	1.7568 (17)	C14—H14	0.9500
O16—C16	1.374 (2)	C15—C16	1.387 (2)
O16—C19	1.428 (2)	C15—H15	0.9500
O23—C23	1.371 (2)	C16—C17	1.387 (3)
O23—C26	1.425 (3)	C17—C18	1.384 (2)
C3—C4	1.343 (2)	C17—H17	0.9500
C3—C7	1.471 (2)	C18—H18	0.9500
C4—C5	1.446 (2)	C19—H19A	0.9800
C4—H4	0.9500	C19—H19B	0.9800
C5—C6	1.362 (2)	C19—H19C	0.9800
C6—C20	1.479 (2)	C20—C25	1.394 (2)
C6—C13	1.492 (2)	C20—C21	1.405 (2)
C7—C8	1.392 (2)	C21—C22	1.375 (3)
C7—C12	1.393 (2)	C21—H21	0.9500
C8—C9	1.388 (3)	C22—C23	1.390 (3)
C8—H8	0.9500	C22—H22	0.9500
C9—C10	1.375 (3)	C23—C24	1.386 (3)
C9—H9	0.9500	C24—C25	1.395 (2)
C10—C11	1.384 (3)	C24—H24	0.9500
C10—H10	0.9500	C25—H25	0.9500
C11—C12	1.372 (3)	C26—H26A	0.9800
C11—H11	0.9500	C26—H26B	0.9800
C12—H12	0.9500	C26—H26C	0.9800
C13—C14	1.389 (2)

C5—S1—S2	96.33 (6)	C16—C15—H15	120.2
C3—S2—S1	94.22 (6)	C14—C15—H15	120.2
C16—O16—C19	117.06 (14)	O16—C16—C15	124.15 (16)
C23—O23—C26	117.24 (15)	O16—C16—C17	116.15 (15)
C4—C3—C7	125.56 (15)	C15—C16—C17	119.70 (16)
C4—C3—S2	116.95 (13)	C18—C17—C16	120.22 (16)
C7—C3—S2	117.35 (12)	C18—C17—H17	119.9
C3—C4—C5	120.21 (15)	C16—C17—H17	119.9
C3—C4—H4	119.9	C17—C18—C13	121.12 (17)
C5—C4—H4	119.9	C17—C18—H18	119.4
C6—C5—C4	125.84 (15)	C13—C18—H18	119.4
C6—C5—S1	122.73 (13)	O16—C19—H19A	109.5
C4—C5—S1	111.42 (12)	O16—C19—H19B	109.5
C5—C6—C20	123.39 (15)	H19A—C19—H19B	109.5
C5—C6—C13	119.74 (15)	O16—C19—H19C	109.5
C20—C6—C13	116.80 (14)	H19A—C19—H19C	109.5
C8—C7—C12	118.38 (16)	H19B—C19—H19C	109.5
C8—C7—C3	121.58 (16)	C25—C20—C21	117.06 (16)
C12—C7—C3	120.03 (16)	C25—C20—C6	123.17 (15)
C9—C8—C7	120.70 (18)	C21—C20—C6	119.78 (16)
C9—C8—H8	119.7	C22—C21—C20	121.28 (17)
C7—C8—H8	119.7	C22—C21—H21	119.4
C10—C9—C8	120.12 (19)	C20—C21—H21	119.4
C10—C9—H9	119.9	C21—C22—C23	120.56 (17)
C8—C9—H9	119.9	C21—C22—H22	119.7
C9—C10—C11	119.43 (18)	C23—C22—H22	119.7
C9—C10—H10	120.3	O23—C23—C24	124.82 (17)
C11—C10—H10	120.3	O23—C23—C22	115.35 (16)
C12—C11—C10	120.82 (19)	C24—C23—C22	119.80 (16)
C12—C11—H11	119.6	C23—C24—C25	119.07 (16)
C10—C11—H11	119.6	C23—C24—H24	120.5
C11—C12—C7	120.54 (18)	C25—C24—H24	120.5
C11—C12—H12	119.7	C20—C25—C24	122.21 (16)
C7—C12—H12	119.7	C20—C25—H25	118.9
C14—C13—C18	117.70 (16)	C24—C25—H25	118.9
C14—C13—C6	121.75 (15)	O23—C26—H26A	109.5
C18—C13—C6	120.49 (16)	O23—C26—H26B	109.5
C13—C14—C15	121.67 (16)	H26A—C26—H26B	109.5
C13—C14—H14	119.2	O23—C26—H26C	109.5
C15—C14—H14	119.2	H26A—C26—H26C	109.5
C16—C15—C14	119.59 (17)	H26B—C26—H26C	109.5

S1—S2—C3—C4	−5.04 (14)	C18—C13—C14—C15	0.7 (3)
S1—S2—C3—C7	178.96 (12)	C6—C13—C14—C15	178.01 (16)
C7—C3—C4—C5	174.91 (16)	C13—C14—C15—C16	−0.7 (3)
S2—C3—C4—C5	−0.7 (2)	C19—O16—C16—C15	2.8 (3)
C3—C4—C5—C6	−171.60 (18)	C19—O16—C16—C17	−176.79 (17)
C3—C4—C5—S1	7.5 (2)	C14—C15—C16—O16	−179.13 (16)
S2—S1—C5—C6	170.12 (15)	C14—C15—C16—C17	0.4 (3)
S2—S1—C5—C4	−9.01 (13)	O16—C16—C17—C18	179.34 (16)
C4—C5—C6—C20	−177.17 (16)	C15—C16—C17—C18	−0.2 (3)
S1—C5—C6—C20	3.8 (3)	C16—C17—C18—C13	0.3 (3)
C4—C5—C6—C13	5.9 (3)	C14—C13—C18—C17	−0.5 (3)
S1—C5—C6—C13	−173.05 (13)	C6—C13—C18—C17	−177.85 (17)
C4—C3—C7—C8	152.20 (18)	C5—C6—C20—C25	39.0 (3)
S2—C3—C7—C8	−32.2 (2)	C13—C6—C20—C25	−144.05 (17)
C4—C3—C7—C12	−29.1 (3)	C5—C6—C20—C21	−140.87 (18)
S2—C3—C7—C12	146.55 (14)	C13—C6—C20—C21	36.1 (2)
C12—C7—C8—C9	0.9 (3)	C25—C20—C21—C22	−1.8 (3)
C3—C7—C8—C9	179.62 (17)	C6—C20—C21—C22	178.06 (17)
C7—C8—C9—C10	−0.6 (3)	C20—C21—C22—C23	1.5 (3)
C8—C9—C10—C11	0.4 (3)	C26—O23—C23—C24	−1.1 (3)
C9—C10—C11—C12	−0.6 (3)	C26—O23—C23—C22	−179.63 (18)
C10—C11—C12—C7	0.9 (3)	C21—C22—C23—O23	178.62 (17)
C8—C7—C12—C11	−1.0 (3)	C21—C22—C23—C24	0.0 (3)
C3—C7—C12—C11	−179.76 (17)	O23—C23—C24—C25	−179.54 (16)
C5—C6—C13—C14	53.4 (2)	C22—C23—C24—C25	−1.1 (3)
C20—C6—C13—C14	−123.65 (18)	C21—C20—C25—C24	0.7 (2)
C5—C6—C13—C18	−129.38 (19)	C6—C20—C25—C24	−179.14 (15)
C20—C6—C13—C18	53.5 (2)	C23—C24—C25—C20	0.7 (3)

Selected geometric parameters (Å, °) for 10 and related compounds top

The atom numbers refer to the structure model for 10. Other atom-numbering schemes may have been used for the other entries; the entries refer to the corresponding chemical parts of the structures.

	10	MEFFAF*	DTBPTR01	NURYEE	Microwave**	22 structures without tert-butyl
						Range, mean
S1—C1	1.8381 (12)	1.8185 (15), 1.8233 (15)	1.823 (2)	1.818 (2)	1.819	1.802–1.856, 1.824 (11)
S1—C2	1.8493 (12)	1.8334 (16), 1.8245 (16)	1.847 (2)	1.841 (2)	1.819	1.785–1.854, 1.826 (17)
C1—C2	1.5041 (18)	1.516 (2), 1.508 (2)	1.549 (3)	1.539 (2)	1.492	1.508–1.556, 1.535 (13)
C1—C8	1.5152 (16)	1.512 (2), 1.507 (2)	1.516 (3)	1.505 (3)	–	1.489–1.543, 1.513 (11)
C1—C15	1.5151 (17)	1.514 (2), 1.525 (2)	1.535 (3)	1.509 (3)	–	1.489–1.543, 1.513 (11)
C2—C3	1.5160 (17)	1.530 (2), 1.528 (2)	1.588 (3)	1.567 (4)	–	1.490–1.562, 1.519 (13)
C2—C7	1.5156 (17)	1.532 (2), 1.541 (2)	1.598 (3)	1.542 (4)	–	1.490–1.562, 1.519 (13)
C1—S1—C2	48.14 (6)	49.05 (7), 48.84 (7)	49.9 (9)	49.76 (8)	65.8	48.8–50.55, 49.7 (5)
S1—C2—C1	65.54 (7)	65.99 (8), 65.62 (8)	64.2 (9)	64.35 (10)	not given	63.9–66.4, 65.3 (7)
S1—C1—C2	66.32 (7)	64.96 (8), 64.54 (8)	65.9 (9)	65.89 (11)	not given	63.9–66.2, 65.0 (7)
C8—C1—C15	113.92 (10)	112.57 (13), 112.48 (13)	104.0 (2)	108.23 (16)	–	104.0–116.7, 111 (4)
C3—C2—C7	113.01 (11)	102.50 (12), 102.54 (12)	118.3 (2)	110.94 (17)	–	102.5–118.8, 111 (5)

Notes: (*) two molecules in the asymmetric unit. (**) Structure from experimental microwave data (Cunningham et al., 1951); result reproduced exactly by MO–SCF calculations (Rohmer & Roos, 1975).

Selected geometric parameters (Å, °) for 11 and related compounds top

The atom numbers refer to the structure model for 11. Other atom-numbering schemes may have been used for the other entries; the entries refer to the corresponding chemical parts of the structures.

	11	10	AOPCHY	DEQTOJ
C1—C2	1.340 (3)	1.5041 (18)	1.339	1.344 (3)
C1—C8	1.498 (3)	1.5152 (16)	1.495	1.511 (3)
C1—C15	1.495 (3)	1.5151 (17)	1.542	1.505 (3)
C2—C3	1.510 (3)	1.5160 (17)	1.500	1.513 (3)
C2—C7	1.514 (3)	1.5156 (17)	1.549	1.515 (3)
C8—C1–C15	113.49 (16)	113.92 (10)	115.4	117.8 (2)
C3—C2–C7	111.92 (17)	113.01 (11)	112.8	112.3 (2)

Intermolecular C—H···π interactions (Å, °) for 11 top

Cg1 and Cg2 are the centroids of the C8–C13 and C15–C20 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4B···Cg2ⁱ	0.99	2.96	3.888 (3)	157
C6—H6A···Cg1ⁱⁱ	0.99	2.96	3.820 (3)	146
C14—H14A···Cg1ⁱⁱⁱ	0.98	2.88	3.737 (2)	147

Symmetry codes: (i) -x+1, -y, -z; (ii) -x+1, y-1/2, -z+1/2; (iii) -x+2, y+1/2, -z+1/2.

Selected geometric parameters (Å, °) for 13 and related compounds top

The atom numbers refer to the structure model for 13. Other atom-numbering schemes may have been used for the other entries; the entries refer to the corresponding chemical parts of the structures.

	13	GANGUX*	CPTYBN10	XPTHYC
S1—S2	2.0826 (6)	2.041 (5), 2.051 (4)	2.072 (4)	2.053
S1—C5	1.7797 (17)	1.735 (12), 1.732 (12)	1.74 (1)	1.772
S2—C3	1.7568 (17)	1.714 (11), 1.734 (12)	1.730 (8)	1.732
C3—C4	1.342 (2)	1.36 (2), 1.36 (2)	1.35 (1)	1.379
C3—C7	1.471 (2)	1.47 (2), 1.47 (2)	1.47 (1)	1.451
C4—C5	1.446 (2)	1.40 (2), 1.41 (2)	1.42 (1)	1.404
C5—C6	1.362 (2)	1.44 (2), 1.42 (2)	1.39 (1)	1.404
C6—C13	1.492 (2)	1.41 (2), 1.39 (2)	1.40 (1)	1.451
C6—C20	1.479 (2)	1.51 (2), 1.50 (2)	-	1.394
S2—S1—C5	96.33 (6)	95.6 (9), 96.0 (4)	96.5 (9)	95.8
S1—S2—C3	94.22 (6)	96.2 (8), 95.6 (5)	95.0 (9)	96.1
S2—C3—C4	116.95 (13)	114.6 (10), 114.9 (10)	115.4 (9)	115.0
C3—C4—C5	120.21 (15)	120.6 (11), 120.1 (12)	121.2 (9)	120.4
S1—C5—C4	111.42 (12)	112.9 (11), 113.4 (9)	111.9 (9)	112.7
C13—C6—C20	116.80 (14)	126.3 (11), 124.8 (10)	-	118.2

Note: (*) two 1,2-dithiole-3H-3-ylidene entities in the cation.

Intramolecular C—H···S and intermolecular C—H···O and C—H···π interactions (Å, °) for 13 top

Cg3 and Cg4 are the centroids of the C13–C18 and C20–C25 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···S2	0.95	2.77	3.1236 (19)	103
C25—H25···S1	0.95	2.59	3.0503 (19)	110
C8—H8···O16ⁱ	0.95	2.59	3.413 (2)	146
C10—H10···Cg3ⁱⁱ	0.99	2.96	3.888 (3)	157
C14—H14···Cg4ⁱⁱⁱ	0.99	2.96	3.820 (3)	146

Symmetry codes: (i) x+1/2, -y-1/2, z+1/2; (ii) -x+2, -y-1, -z; (iii) x, y-1, z.

Footnotes

‡Part of a Diploma thesis, University of Zurich, 2002

Acknowledgements

Heinz Heimgartner is grateful for funding for this research from Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung and F. Hoffmann–La Roche AG, Basel, Switzerland. Open access publishing facilitated by Universitat Zurich, as part of the Wiley–Universitat Zurich agreement via the Consortium Of Swiss Academic Libraries.

References

Ager, D. J. (1984). Synthesis, 1984, 384–398. CrossRef Google Scholar
Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435. CrossRef Web of Science IUCr Journals Google Scholar
Barton, D. H. R., Guziec, F. S. & Shahak, I. (1974). J. Chem. Soc. Perkin Trans. 1, pp. 1794–1799. CrossRef Web of Science Google Scholar
Baudin, J. B., Hareau, G., Julia, S. A. & Ruel, O. (1993). Bull. Soc. Chim. Fr. 130, 336–357. CAS Google Scholar
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Bodwell, G. J. & Nandaluru, P. R. (2012). Isr. J. Chem. 52, 105–138. Web of Science CrossRef CAS Google Scholar
Bongso, A., Roswanda, R. & Syah, Y. M. (2022). RSC Adv. 12, 15885–15909. Web of Science CrossRef CAS PubMed Google Scholar
Britten, T. K. & McLaughlin, M. G. (2020). J. Org. Chem. 85, 301–305. Web of Science CrossRef CAS PubMed Google Scholar
Burns, J. M., Clark, T. & Williams, C. M. (2021). J. Org. Chem. 86, 7515–7528. Web of Science CrossRef CAS PubMed Google Scholar
Byrne, P. A. & Gilheany, D. G. (2013). Chem. Soc. Rev. 42, 6670–6696. Web of Science CrossRef CAS PubMed Google Scholar
Chrenko, D. & Pospíšil, J. (2024). Molecules, 29, 2719. Web of Science CrossRef PubMed Google Scholar
Cunningham, G. L. Jr, Boyd, A. W., Myers, R. J., Gwinn, W. D. & Le Van, W. I. (1951). J. Chem. Phys. 19, 676–685. CrossRef CAS Web of Science Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Duan, X.-F., Zeng, J., Lü, J.-W. & Zhang, Z.-B. (2006). J. Org. Chem. 71, 9873–9876. Web of Science CrossRef PubMed CAS Google Scholar
Egli, D. H., Linden, A. & Heimgartner, H. (2007). Helv. Chim. Acta, 90, 86–100. Web of Science CSD CrossRef CAS Google Scholar
Ephritikhine, M. (1998). Chem. Commun. pp. 2549–2554. Web of Science CrossRef Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Guziec, F. S. & Sanfilippo, L. J. (1988). Tetrahedron, 44, 6241–6285. CrossRef CAS Web of Science Google Scholar
Heravi, M. M., Zadsirjan, V., Daraie, M. & Ghanbarian, M. (2020). ChemistrySelect, 5, 9654–9690. Web of Science CrossRef CAS Google Scholar
Hordvik, A., Jynge, K. & Hansen, L. K. (1988). Acta Chem. Scand. 42a, 79–86. CSD CrossRef Web of Science Google Scholar
Hu, Y. & Wang, C. (2019). ChemCatChem, 11, 1167–1174. Web of Science CrossRef CAS Google Scholar
Huisgen, R., Fulka, C., Kalwinsch, I., Xingya, L., Mlostoń, G., Moran, J. R. & Pröbstl, A. (1984). Bull. Soc. Chim. 93, 511–532. CrossRef CAS Google Scholar
Kägi, M., Linden, A., Heimgartner, H. & Mlostoń, G. (1993). Helv. Chim. Acta, 76, 1715–1728. Google Scholar
Kägi, M., Linden, A., Mlostoń, G. & Heimgartner, H. (1998). Helv. Chim. Acta, 81, 285–302. Google Scholar
Kägi, M., Mlostoń, G. & Heimgartner, H. (1998). Pol. J. Chem. 72, 678–687. Google Scholar
Kellogg, R. M. (1976). Tetrahedron, 32, 2165–2184. CrossRef CAS Web of Science Google Scholar
Koley, S., Chanda, T., Samai, S. & Singh, M. S. (2016). J. Org. Chem. 81, 11594–11602. Web of Science CSD CrossRef CAS PubMed Google Scholar
Maryanoff, B. E. & Reitz, A. B. (1989). Chem. Rev. 89, 863–927. CrossRef CAS Web of Science Google Scholar
Mathur, P., Avasare, V. D., Ghosh, A. K. & Mobin, S. M. (2004). J. Organomet. Chem. 689, 1325–1327. Web of Science CSD CrossRef CAS Google Scholar
Mlostoń, G., Celeda, M., Linden, A. & Heimgartner, H. (2006). Heterocycles, 68, 33–45. Google Scholar
Mlostoń, G., Hamera-Fałdyga, R., Celeda, M. & Heimgartner, H. (2018). Org. Biomol. Chem. 16, 4350–4356. Web of Science PubMed Google Scholar
Mlostoń, G. & Heimgartner, H. (1992). Helv. Chim. Acta, 75, 1825–1833. Google Scholar
Mlostoń, G., Jasiński, R., Kula, K. & Heimgartner, H. (2020). Eur. J. Org. Chem. 2020, 176–182. Google Scholar
Mlostoń, G., Petit, M., Linden, A. & Heimgartner, H. (1994). Helv. Chim. Acta, 77, 435–444. Google Scholar
Mlostoń, G., Romański, J. & Heimgartner, H. (2002). Pol. J. Chem. 76, 551–555. Google Scholar
Mlostoń, G., Urbaniak, K., Pawlak, A. & Heimgartner, H. (2016). Heterocycles, 93, 127–139. Google Scholar
Mugnoli, A. & Simonetta, M. (1976). Acta Cryst. B32, 1762–1766. CSD CrossRef CAS IUCr Journals Google Scholar
Murphy, P. J. & Brennan, J. (1988). Chem. Soc. Rev. 17, 1–30. CrossRef CAS Web of Science Google Scholar
Nguyen-Huy-Dong & Etienne, J. (1978). Acta Cryst. B34, 683–686. Google Scholar
Nonius (2000). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Pedersen, B. S., Scheibye, S., Nilsson, N. H. & Lawesson, S. O. (1978). Bull. Soc. Chim. 87, 223–228. CrossRef CAS Google Scholar
Precigoux, G., Busetta, B., Courseille, C. & Hospital, M. (1972). Cryst. Struct. Commun. 1, 341–344. CAS Google Scholar
Rakitin, O. A. (2021). Molecules, 26, 3595. Web of Science CrossRef PubMed Google Scholar
Rocha, D. H. A., Pinto, D. C. G. A. & Silva, A. M. S. (2018). Eur. J. Org. Chem. 2018, 2443–2457. Web of Science CrossRef CAS Google Scholar
Rohmer, M.-M. & Roos, B. (1975). J. Am. Chem. Soc. 97, 2025–2030. CrossRef CAS Web of Science Google Scholar
Sakaine, G., Leitis, Z., Ločmele, R. & Smits, G. (2023). Eur. J. Org. Chem. 26, e202201217. Web of Science CrossRef Google Scholar
Schmidt, T. A. & Sparr, C. (2021). Angew. Chem. Int. Ed. 60, 23911–23916. Web of Science CSD CrossRef CAS Google Scholar
Seif, A., Ahmadi, T. S. & Klein, A. (2022). New J. Chem. 46, 10907–10919. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2020). Acta Cryst. E76, 1–11. Web of Science CrossRef IUCr Journals Google Scholar
Staden, L. F. van, Gravestock, D. & Ager, D. J. (2002). Chem. Soc. Rev. 31, 195–200. Web of Science CrossRef PubMed Google Scholar
Sun, H., Hua, R., Chen, S. & Yin, Y. (2006). Adv. Synth. Catal. 348, 1919–1925. Web of Science CSD CrossRef CAS Google Scholar
Takeda, T. (2014). Editor. Modern Carbonyl Olefination: Methods and Applications. Weinheim: Wiley-VCH. Google Scholar
Wei, C. H. (1986). Acta Cryst. C42, 1836–1839. CSD CrossRef CAS IUCr Journals Google Scholar
Wei, K.-T. H., Greensley, M. K., Paul, I. C., Le Coustumer, G., Pinel, R. & Mollier, Y. (1977). Cryst. Struct. Commun. 6, 425. Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zabrodsky, H., Peleg, S. & Avnir, D. (1993). J. Am. Chem. Soc. 115, 8278–8289. CrossRef CAS Web of Science Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 81| Part 4| April 2025| Pages 238-245

https://doi.org/10.1107/S2053229625002074

Open

access