(1R,2R,3R,4S,5S)-3-Methyl-8-oxa­bicyclo­[3.2.1]oct-6-ene-2,4-diyl diacetate

Tafeenko, V.A.; Aslanov, L.A.; Proskurnina, M.V.; Sosonyuk, S.E.; Khlevin, D.A.

doi:10.1107/S1600536811027292

organic compounds

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ISSN: 2056-9890

Volume 67| Part 8| August 2011| Pages o2127-o2128

doi:10.1107/S1600536811027292

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(1R,2R,3R,4S,5S)-3-Methyl-8-oxabicyclo[3.2.1]oct-6-ene-2,4-diyl diacetate

Viktor A. Tafeenko,^a Leonid A. Aslanov,^a ^* Marina V. Proskurnina,^a Sergei E. Sosonyuk ^a and Dmitrii A. Khlevin ^a

^aChemistry Department, Moscow State University, 119991 Moscow, Russian Federation
^*Correspondence e-mail: aslanov@struct.chem.msu.ru

(Received 23 June 2011; accepted 7 July 2011; online 23 July 2011)

The molecule of the title compound, C₁₂H₁₆O₅, has crystallographically imposed mirror symmetry with the mirror plane passing through the endocyclic O atom and the mid-point of the double bond. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming chains running along the a axis.

Related literature

Compounds containing the 8-oxabicyclo[3.2.1]octane framework have shown broad utility as chiral building blocks for synthesis of polyketides, see: Coste & Gerber-Lemaire (2005 ); Meilert et al. (2003 ); Schwenter & Vogel (2001 ); Gerber-Lemaire & Vogel (2003 ); Gerber & Vogel (1999 , 2001 ); Re et al. (2009 ); Pascual et al. (2004 ); Derwick (1998 ). For the inhibitory activity of calystegines and other tropane alkaloids against several glycosidase enzymes, see: Asano et al. (2000 ); Drager (2004 ). Several 8-oxabicyclo[3.2.1] octane derivatives possess moderate anti-HIV activity, see: Montana et al. (2009 ). For the syntheses of a full set of hybrid d- and l-C-glycosides and thymine polyoxin C starting with the unsaturated 8-oxabicyclo[3.2.1]octane framework, see: Gethin & Simpkins (1997 ); Hoffmann et al. (2001 ). For the synthesis of an 8-oxabicyclo[3.2.1]octane from tetrachlorocyclopropene and furan, see: Batson et al. (2004 ). For a synthetic approach to 8-oxabicyclo[3.2.1]octane derivatives based on the reaction of tetrachlorocyclopropene with furan, see: Law & Tobey (1968 ). For structures of related 8-oxabicyclo[3.2.1]octanes, see: Kreiselmeier et al. (2006 ); Hoffmann et al. (2001). For a report of prior research, see: Tafeenko et al. (2009 ).

Experimental

Crystal data

C₁₂H₁₆O₅
M_r = 240.25
Orthorhombic, P n m a
a = 6.8680 (12) Å
b = 12.295 (4) Å
c = 14.120 (3) Å
V = 1192.3 (5) Å³
Z = 4
Ag Kα radiation
λ = 0.56085 Å
μ = 0.06 mm⁻¹
T = 296 K
0.1 × 0.07 × 0.05 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
1974 measured reflections
1974 independent reflections
1085 reflections with I > 2s(I)
2 standard reflections every 120 min intensity decay: none

Refinement

R[F² > 2σ(F²)] = 0.055
wR(F²) = 0.138
S = 1.02
1974 reflections
91 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯O2ⁱ	0.93	2.55	3.482 (2)	178
Symmetry code: (i) x-1, y, z.

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2000 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811027292/mw2015sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811027292/mw2015Isup2.hkl

checkCIF report

Comment top

Compounds containing the 8-oxabicyclo[3.2.1]octane framework are important precursors in the field of biologically active compounds. They have shown broad utility as chiral building blocks for synthesis of polyketides (Coste & Gerber-Lemaire, 2005; Meilert et al., 2003; Schwenter & Vogel, 2001; Gerber-Lemaire & Vogel, 2003), C-linked disaccharides (Gerber & Vogel, 1999; Gerber & Vogel, 2001), calystegines (Re et al., 2009; Pascual et al., 2004; Derwick, 1998) and other natural products. Calystegines and other tropane alkaloids show remarkable inhibitory activities against several glycosidase enzymes, in comparison with other alkaloidal glycosidase inhibitors (Asano et al., 2000; Drager, 2004). They are used medicinally, e.g., as anticholinergics, competing with acetylcholine for the muscarinic receptor site of the parasympathetic nervous system (Derwick, 1998). De novo syntheses of a full set of hybrid d- and l-C-glycosides and thymine polyoxin C starting with the unsaturated 8-oxabicyclo[3.2.1]octane framework have been reported (Hoffmann et al., 2001; Gethin & Simpkins, 1997). Moreover, recent research showed that several 8-oxabicyclo[3.2.1] octane derivatives possess moderate anti-HIV activity (Montana et al., 2009). In studies of novel biologically active homoinositol compounds, including selective glycosidase inhibitors, we have investigated a new synthetic approach to 8-oxabicyclo[3.2.1]octane derivatives based on the reaction of tetrachlorocyclopropene with furan (Law et al., 1968) for the preparation of (1R,2R,3r,4S,5S)-3-methyl-8-oxabicyclo[3.2.1]oct-6-ene- 2,4-diol (4). Several structural results in this field have been previously reported (Tafeenko et al., 2009; Batson et al., 2004; Kreiselmeier et al., 2006; Hoffmann et al. 2001).

Determination of the relative stereochemistry of compound (4) (Fig. 2) by NMR methods was ambiguous so recourse was made to X-ray crystallography for which purpose the crystalline diacetate (I) was synthesized.

Molecule (I) has crystallographically-imposed mirror symmetry with the mirror plane, m, passing through atoms C3, C8, the endocyclic oxygen O8 and the midpoint of the double bond C6/C6ⁱ (i: x,1.5 - y, z). The 6-membered ring of the molecule adopts a chair conformation, with atoms O8 and C3 displaced out of plane defined by the atoms C2/C2ⁱ/C1/C1ⁱ (plane 1) by 0.856 (2) and -0.525 (2) Å, respectively. The carbon atom of the methyl-group and atoms C6,C6ⁱ (double bond) are displaced out of plane 1 by -2.028 (2) Å and -1.326 (2) Å respectively. The molecules (I) are linked by means of weak C—H···O hydrogen bonds to form chains running along a axis.

Related literature top

Compounds containing the 8-oxabicyclo[3.2.1]octane framework have shown broad utility as chiral building blocks for synthesis of polyketides, see: Coste & Gerber-Lemaire (2005); Meilert et al. (2003); Schwenter & Vogel (2001); Gerber-Lemaire & Vogel (2003); Gerber & Vogel (1999, 2001); Re et al. (2009); Pascual et al. (2004); Derwick (1998). Calystegines and other tropane alkaloids show remarkable inhibitory activity against several glycosidase enzymes compared with other alkaloidal glycosidase inhibitors, see: Asano et al. (2000); Drager (2004). Several 8-oxabicyclo[3.2.1] octane derivatives possess moderate anti-HIV activity, see: Montana et al. (2009). For the syntheses of a full set of hybrid d- and l-C-glycosides and thymine polyoxin C starting with the unsaturated 8-oxabicyclo[3.2.1]octane framework, see: Gethin & Simpkins (1997); Hoffmann et al. (2001). For the synthesis of an 8-oxabicyclo[3.2.1]octane from tetrachlorocyclopropene and furan, see: Batson et al. (2004). We have investigated a new synthetic approach to 8-oxabicyclo[3.2.1]octane derivatives based on the reaction of tetrachlorocyclopropene with furan, see: Law & Tobey (1968). For structures of related 8-oxabicyclo[3.2.1]octanes, see: Kreiselmeier et al. (2006); Hoffmann et al. (2001). For a report of prior research, see: Tafeenko et al. (2009).

Experimental top

(1R,5S)-3-Chloro-3-methyl-8-oxabicyclo[3.2.1]oct-6-ene-2,4-dione (see Fig.2) (2).

To a solution of 0.5 g (2.9 mmol) of (1) (Law & Tobey, 1968) in acetone (10 ml) 0.83 g (5.8 mmol) K₂CO₃ and 1.38 g (8.7 mmol) MeI were added. The mixture was stirred at 298 K for 36 h, then concentrated under reduced pressure. The residue was purified via silica gel flash chromatography (10% EtOAc in CH₂Cl₂), to give a pale yellow crystalline solid; yield: 0.45 g, (83%) (compound 2), mp 370–372 K.

(1R,5S)-3-methyl-8-oxabicyclo[3.2.1]oct-6-ene-2,4-dione (see Fig.2) (3).

To a solution of 0.4 g (2.1 mmol) of diketone (2) in 4 ml of glacial acetic acid was added 0.23 g of Zn-powder. After the beginning of heating-up the mixture was stirred at 298 K for 0.5 h and 20% aqueous NaOH was added dropwise until solid formed. The solid was dissolved by addition of 1 ml 0.1 N HCl, the mixture was extracted with CH₂Cl₂ (5*20 ml), the combined organic layers were dried over Na₂SO₄ and evaporated under reduced pressure to yield 0.26 g of compound (3) as a pale yellow crystalline solid, (compound 3) mp 359–361 K.

(1R,2R,4S,5S)-3-methyl-8-oxabicyclo[3.2.1]oct-6-ene-2,4 -diol (see Fig.2) (4).

To a solution of 200 mg (1.3 mmol) of diketone (3) in 15 ml of MeOH 340 mg (8.9 mmol) of NaBH₄ was added portionwise for 3 h, during which time the reaction temperature was kept between 293–303 K. The mixture was stirred at 298 K for 2 h, then 0.4 g of crystalline NH₄Cl was added followed by 0.5 ml of 1 N HCl. The solvents were evaporated under reduced pressure, the residue was flashed by EtOAc/Me₂CO (1:1) through a silica gel column to give 0.2 g of a yellow oil. The ¹H and ¹³C NMR spectra showed that the oil contained several isomers so it was purified by column chromatography on silica gel eluting with a EtOAc/Me₂CO (5:2) mixture to afford 95 mg of the major isomer (4) as a colorless oil, yield 46%; Rf = 0.5 (Et₂O/Me₂CO = 3:1).

(1R,2R,3r,4S,5S)-3-methyl-8-oxabicyclo[3.2.1]oct-6-ene- 2,4-diyl diacetate (see Fig.2) (I).

Compound (4) (95 mg, 0.61 mmol) was dissolved in 5 ml of py and 3 ml of Ac₂O was added. The mixture was stirred for 24 h at room temperature and then concentrated under reduced pressure (1 mm Hg) to give a thick brown oil. Diacetate (I) was separated by flash chromatography on silica gel (CH₂Cl₂) as colorless crystals, yield 134 mg (92%), mp 428–430 K, Rf = 0.4 (CH₂Cl₂). Crystals suitable for diffraction analysis were obtained by slow evaporation of solvents from a dichloromethane-hexane solution.

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level. Atoms C,N,O, and Cⁱ,Nⁱ,Oⁱ are related by symmetry code: (i) x,1.5 - y, z; The H atoms at C8 are not shown for clarity.
	Fig. 2. How the title compound was obtained.

(1R,2R,3R,4S,5S)-3-Methyl-8- oxabicyclo[3.2.1]oct-6-ene-2,4-diyl diacetate top

Crystal data top

C₁₂H₁₆O₅	D_x = 1.338 Mg m⁻³
M_r = 240.25	Melting point: 428 K
Orthorhombic, Pnma	Ag Kα radiation, λ = 0.56085 Å
Hall symbol: -P 2ac 2n	Cell parameters from 25 reflections
a = 6.8680 (12) Å	θ = 11–14°
b = 12.295 (4) Å	µ = 0.06 mm⁻¹
c = 14.120 (3) Å	T = 296 K
V = 1192.3 (5) Å³	Prism, colorless
Z = 4	0.1 × 0.07 × 0.05 mm
F(000) = 512

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.000
Radiation source: fine-focus sealed tube	θ_max = 24.0°, θ_min = 1.7°
Graphite monochromator	h = −9→0
non–profiled ω scans	k = −17→0
1974 measured reflections	l = −20→0
1974 independent reflections	2 standard reflections every 120 min
1085 reflections with I > 2s(I)	intensity decay: none

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.055	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.138	w = 1/[σ²(F_o²) + (0.0492P)² + 0.2946P] where P = (F_o² + 2F_c²)/3
S = 1.02	(Δ/σ)_max < 0.001
1974 reflections	Δρ_max = 0.24 e Å⁻³
91 parameters	Δρ_min = −0.17 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.031 (4)

Crystal data top

C₁₂H₁₆O₅	V = 1192.3 (5) Å³
M_r = 240.25	Z = 4
Orthorhombic, Pnma	Ag Kα radiation, λ = 0.56085 Å
a = 6.8680 (12) Å	µ = 0.06 mm⁻¹
b = 12.295 (4) Å	T = 296 K
c = 14.120 (3) Å	0.1 × 0.07 × 0.05 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.000
1974 measured reflections	2 standard reflections every 120 min
1974 independent reflections	intensity decay: none
1085 reflections with I > 2s(I)

Refinement top

R[F² > 2σ(F²)] = 0.055	0 restraints
wR(F²) = 0.138	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	Δρ_max = 0.24 e Å⁻³
1974 reflections	Δρ_min = −0.17 e Å⁻³
91 parameters

Special details top

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

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
O1	0.74430 (17)	0.55206 (10)	0.09878 (9)	0.0459 (4)
O2	1.06414 (18)	0.53353 (12)	0.12399 (11)	0.0604 (4)
O8	0.6552 (3)	0.7500	−0.08400 (12)	0.0550 (5)
C1	0.6076 (3)	0.65913 (15)	−0.02489 (13)	0.0479 (5)
H1	0.5863	0.5928	−0.0619	0.057*
C2	0.7802 (2)	0.64791 (14)	0.04233 (12)	0.0409 (4)
H2	0.8972	0.6349	0.0042	0.049*
C3	0.8160 (3)	0.7500	0.10391 (17)	0.0382 (6)
H3	0.9552	0.7500	0.1193	0.046*
C6	0.4243 (3)	0.69639 (16)	0.02399 (13)	0.0510 (5)
H6	0.3285	0.6518	0.0496	0.061*
C8	0.7082 (5)	0.7500	0.19833 (19)	0.0494 (7)
C9	0.9005 (3)	0.50142 (15)	0.13532 (13)	0.0451 (4)
C10	0.8443 (3)	0.40349 (17)	0.18986 (17)	0.0647 (6)
H10A	0.9539	0.3554	0.1947	0.097*
H10B	0.7395	0.3669	0.1581	0.097*
H10C	0.8029	0.4246	0.2521	0.097*
H8	0.749 (3)	0.8125 (16)	0.2358 (16)	0.071 (7)*
H81	0.575 (5)	0.7500	0.194 (3)	0.092 (12)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0411 (6)	0.0396 (7)	0.0569 (8)	−0.0008 (6)	0.0002 (6)	0.0067 (6)
O2	0.0422 (8)	0.0569 (9)	0.0820 (10)	0.0018 (7)	0.0016 (7)	0.0071 (8)
O8	0.0746 (13)	0.0542 (11)	0.0362 (9)	0.000	−0.0022 (10)	0.000
C1	0.0580 (11)	0.0423 (10)	0.0434 (9)	−0.0048 (9)	−0.0061 (9)	−0.0032 (8)
C2	0.0420 (9)	0.0387 (9)	0.0420 (9)	−0.0002 (7)	0.0056 (8)	0.0006 (8)
C3	0.0330 (11)	0.0392 (13)	0.0425 (13)	0.000	0.0001 (10)	0.000
C6	0.0403 (9)	0.0602 (11)	0.0524 (11)	−0.0044 (8)	−0.0128 (8)	0.0003 (10)
C8	0.0507 (17)	0.0601 (18)	0.0374 (14)	0.000	0.0003 (13)	0.000
C9	0.0494 (10)	0.0372 (9)	0.0487 (10)	0.0021 (9)	0.0002 (8)	−0.0051 (9)
C10	0.0650 (13)	0.0516 (12)	0.0775 (15)	−0.0036 (11)	−0.0095 (12)	0.0119 (11)

Geometric parameters (Å, º) top

O1—C9	1.344 (2)	C3—C2ⁱ	1.547 (2)
O1—C2	1.444 (2)	C3—H3	0.9800
O2—C9	1.202 (2)	C6—C6ⁱ	1.318 (4)
O8—C1	1.432 (2)	C6—H6	0.9300
C1—C6	1.507 (2)	C8—H8	0.97 (2)
C1—C2	1.525 (2)	C8—H81	0.92 (4)
C1—H1	0.9800	C9—C10	1.481 (3)
C2—C3	1.547 (2)	C10—H10A	0.9600
C2—H2	0.9800	C10—H10B	0.9600
C3—C8	1.525 (4)	C10—H10C	0.9600

C9—O1—C2	116.98 (13)	C2—C3—H3	106.2
C1ⁱ—O8—C1	102.51 (19)	C2ⁱ—C3—H3	106.2
O8—C1—C6	102.74 (16)	C6ⁱ—C6—C1	107.70 (10)
O8—C1—C2	104.80 (15)	C6ⁱ—C6—H6	126.1
C6—C1—C2	113.07 (14)	C1—C6—H6	126.1
O8—C1—H1	111.9	C3—C8—H8	109.7 (13)
C6—C1—H1	111.9	C3—C8—H81	115 (2)
C2—C1—H1	111.9	H8—C8—H81	108.8 (18)
O1—C2—C1	106.53 (14)	O2—C9—O1	122.91 (17)
O1—C2—C3	112.28 (14)	O2—C9—C10	125.48 (18)
C1—C2—C3	113.59 (15)	O1—C9—C10	111.60 (16)
O1—C2—H2	108.1	C9—C10—H10A	109.5
C1—C2—H2	108.1	C9—C10—H10B	109.5
C3—C2—H2	108.1	H10A—C10—H10B	109.5
C8—C3—C2	114.47 (13)	C9—C10—H10C	109.5
C8—C3—C2ⁱ	114.47 (13)	H10A—C10—H10C	109.5
C2—C3—C2ⁱ	108.50 (19)	H10B—C10—H10C	109.5
C8—C3—H3	106.2

C1ⁱ—O8—C1—C6	38.7 (2)	O1—C2—C3—C8	−30.9 (2)
C1ⁱ—O8—C1—C2	−79.64 (19)	C1—C2—C3—C8	90.0 (2)
C9—O1—C2—C1	154.76 (15)	O1—C2—C3—C2ⁱ	−160.12 (11)
C9—O1—C2—C3	−80.30 (19)	C1—C2—C3—C2ⁱ	−39.2 (2)
O8—C1—C2—O1	−175.93 (13)	O8—C1—C6—C6ⁱ	−24.28 (13)
C6—C1—C2—O1	72.93 (19)	C2—C1—C6—C6ⁱ	88.12 (14)
O8—C1—C2—C3	59.93 (19)	C2—O1—C9—O2	1.2 (3)
C6—C1—C2—C3	−51.2 (2)	C2—O1—C9—C10	−178.85 (15)

Symmetry code: (i) x, −y+3/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O2ⁱⁱ	0.93	2.55	3.482 (2)	178

Symmetry code: (ii) x−1, y, z.

Experimental details

Crystal data
Chemical formula	C₁₂H₁₆O₅
M_r	240.25
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	296
a, b, c (Å)	6.8680 (12), 12.295 (4), 14.120 (3)
V (Å³)	1192.3 (5)
Z	4
Radiation type	Ag Kα, λ = 0.56085 Å
µ (mm⁻¹)	0.06
Crystal size (mm)	0.1 × 0.07 × 0.05

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2s(I)] reflections	1974, 1974, 1085
R_int	0.000
(sin θ/λ)_max (Å⁻¹)	0.724

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.055, 0.138, 1.02
No. of reflections	1974
No. of parameters	91
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.17

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2000), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O2ⁱ	0.93	2.55	3.482 (2)	178

Symmetry code: (i) x−1, y, z.

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Volume 67| Part 8| August 2011| Pages o2127-o2128

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