syn-Dispiro­[1,3-dioxolane-2,17′-penta­cyclo­[12.2.1.16,9.02,13.05,10]octa­decane-18′,2′′-[1,3]dioxolane]-7′,15′-diene

Kachlan, R.M.; Ruble, M.C.; Timmerman, J.C.; Etzkorn, M.; Jones, D.S.

doi:10.1107/S1600536810041565

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 66| Part 11| November 2010| Page o2880

https://doi.org/10.1107/S1600536810041565

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syn-Dispiro[1,3-dioxolane-2,17′-pentacyclo[12.2.1.1^6,9.0^2,13.0^5,10]octadecane-18′,2′′-[1,3]dioxolane]-7′,15′-diene

Rulla M. Kachlan,^a Macey C. Ruble,^a Jacob C. Timmerman,^a Markus Etzkorn ^a ^* and Daniel S. Jones ^a ^*

^aDepartment of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
^*Correspondence e-mail: metzkorn@uncc.edu, djones@uncc.edu

(Received 18 August 2010; accepted 14 October 2010; online 20 October 2010)

The title compound, C₂₂H₂₈O₄, is composed of a central octadecane ring and two spiro[bicyclo[2.2.1]hept[2]ene-7,2′-[1,3]dioxolane] units. This polycycle has pseudo twofold symmetry and the central cyclooctane ring has a distorted boat configuration.

Related literature

For related structures, see: Garcia et al. (1991a ,b ); Tenbusch et al. (2010 ). For the chemistry of syn-bisquinoxalines, see: Chou et al. (2005 ); Etzkorn et al. (2010 ).

Experimental

Crystal data

C₂₂H₂₈O₄
M_r = 356.44
Monoclinic, P 2₁ /n
a = 11.4167 (11) Å
b = 6.7354 (7) Å
c = 24.185 (2) Å
β = 103.521 (9)°
V = 1808.2 (3) Å³
Z = 4
Cu Kα radiation
μ = 0.71 mm⁻¹
T = 295 K
0.35 × 0.20 × 0.20 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
8422 measured reflections
3248 independent reflections
2693 reflections with I > 2σ(I)
R_int = 0.045
3 standard reflections every 79 reflections intensity decay: 2%

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.106
S = 1.05
3248 reflections
236 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ); cell refinement: CAD-4 EXPRESS; 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: ORTEP-3 for Windows (Farrugia, 1997 ) and Mercury (Macrae, et al., 2006 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810041565/su2208sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810041565/su2208Isup2.hkl

checkCIF report

Comment top

The title compound is of interest as a non-chlorinated tether unit for syn-bisquinoxaline molecular tweezers. The non-chlorinated compounds are anticipated to display higher solubility in common organic solvents, thus facilitating the quantitative investigation of host–guest chemistry in solution. The title polycyclic molecule, 3, presented here was obtained by a twofold Diels-Alder reaction of cyclooctadiene and a cyclopentadieneone derivative, 1, followed by subsequent dehalogenation (Fig. 1). Larger molecular frameworks that incorporate scaffold 2a can be found in syn-bisquinoxalines that have previously been investigated for their luminescent properties (Chou et al., 2005) and for their behavior as molecular tweezers (Etzkorn et al., 2010). Compound 3 stems from the chlorinated derivative 2a, which was separated from its anti-isomer 2b via repeated recrystallization from diethyl ether, i.e., the ether solution becomes more enriched in syn-isomer 2a. To improve the solubility of any molecular framework that is derived from scaffold 2a, we reduced the latter with sodium metal in ethanol and liquid ammonia to furnish 3 in good yield. The fully dechlorinated compound 3 did indeed show improved solubility in common organic solvents and, upon further functionalization to tweezer scaffolds, is expected to improve overall solubility.

The title molecule, 3, has pseudo 2-fold symmetry. The central cyclooctane has a distorted boat configuration (Fig. 2). The dioxalane ring (O1,C13,O2,C20,C19) has an envelope configuration with atom O2 at the flap, while ring (O3,C18,O4,C22,C21) has a half-chair configuration being twised about bond O4-C22.

A literature search revealed three related crystal structures. The first (Garcia et al., 1991a) is similar to 3, but has the anti-orientation and an open ketal structure on each of the bridgehead carbon atoms. The second (Tenbusch et al., 2010) is an octachloro derivative with the anti-orientation. The third (Garcia et al., 1991b) is an octachloro syn-structure with an open ketal arrangement on each of the bridgehead carbon atoms; this structure assumes the same distorted boat configuration as does compound 3.

Related literature top

For related structures, see: Garcia et al. (1991a,b); Tenbusch et al. (2010). For related chemistry of syn-bisquinoxalines, see: Chou et al. (2005); Etzkorn et al. (2010).

Experimental top

The synthesis of the title compound, 3, is described in Fig. 1. A mixture of cycloocatdiene (3 g, 29 mmol) and spiroketal (1) (15 g, 57 mmol) was refluxed in toluene (3 ml) for three hours. The off-white paste was filtered, washed with methylene chloride (75 ml), dried, and washed again with cold methanol (15 ml) to remove traces of the mono-Diels-Alder adduct. The remaining colorless solid (14.5 g, 83%) was composed of a mixture of 2a and 2 b in a 1:4 ratio, respectively. After repeated recrystallization from diethyl ether, the pure syn-isomer 2a was obtained as colorless platelets (3.7 g, 21%).

A solution of 2a (1 g, 1.58 mmol) and THF (20 ml) was added to a mixture of liquid ammonia (250 ml) and ethanol (1.5 ml). Pieces of sodium metal (0.8 g, 29.6 mmol) were slowly added over two hours; the reaction mixture was then stirred for an additional hour. The reaction was quenched with solid ammonium chloride, and the ammonia was allowed to evaporate. The residue was taken up in water (75 ml) and the aqueous phase was extracted with methylene chloride (4 x 50 ml) to yield 3 as light-brown crystals (0.490 g). Purification of 3 by column chromatography (cyclohexane: ethyl acetate [4:1], R_f= 0.11) afforded colorless crystals (0.439 g, 78%); Mp.>568 K. IR (KBr): ~ν = 2955, 2856 (CH₂), 1649 (C═C), 1473 (CH₂ bend), 1303, 1290 (C—O—C), 1243, 1224, 1084, 1046, 819, 725 cm^-1; ¹H NMR (CDCl₃; 300 MHz):δ = 6.18 (m, 4H, H-7',-8',-15',-16'), 3.98–3.90 (m, 4H, H-4,-4"), 3.85–3.76 (m, 4H, H-5,-5"), 2.86–2.72 (m, 4H, H-2',-5',-10'-13'), 2.46–2.4 (m, 4H, H-1',-6',-9',-13'); ¹³C NMR (CDCl₃; 75.6 MHz):δ = 133.7 (C-7',-8',-15',-16'), 124.8 (C-17',-18'), 64.8 (C-4,-4"), 64.1 (C-5,-5"), 53.6 (C-2',-5',-10',-13'), 37.4 (C-1',-6', -9',-14'), 25.3 (C-3',-4',-11',-10').

Structure description top

For related structures, see: Garcia et al. (1991a,b); Tenbusch et al. (2010). For related chemistry of syn-bisquinoxalines, see: Chou et al. (2005); Etzkorn et al. (2010).

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); 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: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae, et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. Synthesis scheme.
	Fig. 2. A view of the molecular structure of compound 3, with 50% probability displacement ellipsoids.

syn-Dispiro[1,3-dioxolane-2,17'-pentacyclo [12.2.1.1^6,9.0^2,13.0^5,\10]octadecane-18',2''-[1,3]dioxolane]-7',15'-diene top

Crystal data top

C₂₂H₂₈O₄	F(000) = 768
M_r = 356.44	D_x = 1.309 Mg m⁻³
Monoclinic, P2₁/n	Cu Kα radiation, λ = 1.54184 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 11.4167 (11) Å	θ = 15.3–42.6°
b = 6.7354 (7) Å	µ = 0.71 mm⁻¹
c = 24.185 (2) Å	T = 295 K
β = 103.521 (9)°	Prism, colorless
V = 1808.2 (3) Å³	0.35 × 0.20 × 0.20 mm
Z = 4

Data collection top

Enraf–Nonius CAD-4 diffractometer	θ_max = 67.5°, θ_min = 3.8°
Non–profiled ω/2θ scans	h = −13→0
8422 measured reflections	k = −8→8
3248 independent reflections	l = −28→28
2693 reflections with I > 2σ(I)	3 standard reflections every 79 reflections
R_int = 0.045	intensity decay: 2%

Refinement top

Refinement on F²	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0414P)² + 0.4578P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.039	(Δ/σ)_max < 0.001
wR(F²) = 0.106	Δρ_max = 0.24 e Å⁻³
S = 1.05	Δρ_min = −0.19 e Å⁻³
3248 reflections	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
236 parameters	Extinction coefficient: 0.0117 (6)
0 restraints

Crystal data top

C₂₂H₂₈O₄	V = 1808.2 (3) Å³
M_r = 356.44	Z = 4
Monoclinic, P2₁/n	Cu Kα radiation
a = 11.4167 (11) Å	µ = 0.71 mm⁻¹
b = 6.7354 (7) Å	T = 295 K
c = 24.185 (2) Å	0.35 × 0.20 × 0.20 mm
β = 103.521 (9)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.045
8422 measured reflections	3 standard reflections every 79 reflections
3248 independent reflections	intensity decay: 2%
2693 reflections with I > 2σ(I)

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.106	H-atom parameters constrained
S = 1.05	Δρ_max = 0.24 e Å⁻³
3248 reflections	Δρ_min = −0.19 e Å⁻³
236 parameters

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

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

	x	y	z	U_iso*/U_eq
O1	0.49270 (9)	0.9050 (2)	−0.18532 (5)	0.0544 (4)
O2	0.56491 (10)	1.0106 (2)	−0.25975 (4)	0.0545 (4)
O3	0.58431 (10)	0.6331 (2)	0.05326 (5)	0.0597 (4)
O4	0.68575 (10)	0.66022 (19)	0.14523 (4)	0.0534 (4)
C1	0.68153 (12)	1.0631 (2)	−0.10437 (6)	0.0351 (4)
C2	0.72139 (12)	0.8459 (2)	−0.11521 (6)	0.0360 (4)
C3	0.84705 (13)	0.7735 (2)	−0.08405 (6)	0.0419 (5)
C4	0.87904 (12)	0.7689 (2)	−0.01860 (6)	0.0413 (5)
C5	0.77291 (12)	0.7502 (2)	0.00928 (6)	0.0348 (4)
C6	0.70386 (12)	0.9466 (2)	0.01680 (6)	0.0362 (4)
C7	0.75302 (14)	1.1468 (2)	0.00213 (6)	0.0423 (5)
C8	0.76760 (13)	1.1811 (2)	−0.05857 (6)	0.0399 (5)
C9	0.65659 (13)	1.1569 (2)	−0.16468 (6)	0.0416 (5)
C10	0.80267 (14)	0.9816 (3)	−0.19355 (7)	0.0535 (6)
C11	0.77312 (14)	1.1653 (3)	−0.18360 (6)	0.0509 (6)
C12	0.70828 (13)	0.8439 (3)	−0.18100 (6)	0.0445 (5)
C13	0.59793 (13)	0.9774 (3)	−0.20041 (6)	0.0430 (5)
C14	0.80596 (13)	0.6639 (2)	0.07062 (6)	0.0408 (5)
C15	0.89060 (14)	0.8058 (3)	0.10824 (6)	0.0484 (5)
C16	0.82908 (15)	0.9654 (3)	0.11512 (6)	0.0500 (5)
C17	0.70117 (14)	0.9382 (2)	0.08140 (6)	0.0428 (5)
C18	0.68912 (13)	0.7153 (2)	0.08916 (6)	0.0419 (5)
C19	0.39160 (16)	0.9459 (4)	−0.23040 (8)	0.0676 (7)
C20	0.44134 (16)	1.0615 (3)	−0.27232 (8)	0.0645 (7)
C21	0.53301 (14)	0.4946 (3)	0.08401 (7)	0.0488 (5)
C22	0.62046 (16)	0.4807 (3)	0.14092 (8)	0.0564 (6)
H1	0.60440	1.05420	−0.09330	0.0420*
H2	0.66180	0.75390	−0.10640	0.0430*
H3A	0.90590	0.85690	−0.09600	0.0500*
H3B	0.85730	0.64010	−0.09730	0.0500*
H4A	0.93320	0.65830	−0.00620	0.0500*
H4B	0.92250	0.88970	−0.00490	0.0500*
H5	0.71460	0.65960	−0.01410	0.0420*
H6	0.62090	0.93370	−0.00570	0.0430*
H7C	0.70030	1.24980	0.01050	0.0510*
H7D	0.83120	1.16620	0.02780	0.0510*
H8C	0.75610	1.32130	−0.06740	0.0480*
H8D	0.84950	1.14760	−0.05990	0.0480*
H9	0.60900	1.27950	−0.16970	0.0500*
H10	0.87030	0.94370	−0.20620	0.0640*
H11	0.81640	1.27930	−0.18760	0.0610*
H12	0.70340	0.71250	−0.19880	0.0530*
H14	0.82980	0.52380	0.07380	0.0490*
H15	0.97210	0.78450	0.12390	0.0580*
H16	0.85920	1.07580	0.13700	0.0600*
H17	0.64040	1.02140	0.09280	0.0510*
H19G	0.33210	1.02310	−0.21700	0.0810*
H19H	0.35450	0.82380	−0.24720	0.0810*
H20E	0.40210	1.02430	−0.31100	0.0770*
H20F	0.43090	1.20290	−0.26760	0.0770*
H21A	0.52350	0.36670	0.06510	0.0590*
H21B	0.45480	0.53980	0.08820	0.0590*
H22C	0.57840	0.46940	0.17130	0.0680*
H22D	0.67340	0.36730	0.14240	0.0680*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0405 (6)	0.0779 (9)	0.0398 (6)	−0.0133 (5)	−0.0009 (4)	0.0090 (6)
O2	0.0556 (6)	0.0750 (9)	0.0288 (5)	0.0006 (6)	0.0017 (5)	0.0037 (5)
O3	0.0506 (6)	0.0824 (9)	0.0389 (6)	−0.0342 (6)	−0.0039 (5)	0.0101 (6)
O4	0.0637 (7)	0.0621 (8)	0.0314 (6)	−0.0194 (6)	0.0048 (5)	0.0056 (5)
C1	0.0343 (7)	0.0386 (8)	0.0312 (7)	−0.0020 (6)	0.0055 (5)	0.0016 (6)
C2	0.0367 (7)	0.0384 (8)	0.0319 (7)	−0.0039 (6)	0.0061 (5)	0.0006 (6)
C3	0.0398 (7)	0.0443 (9)	0.0424 (8)	0.0042 (6)	0.0113 (6)	0.0030 (7)
C4	0.0342 (7)	0.0452 (9)	0.0412 (8)	0.0014 (6)	0.0021 (6)	0.0035 (7)
C5	0.0355 (7)	0.0340 (8)	0.0311 (7)	−0.0065 (6)	0.0000 (5)	−0.0010 (6)
C6	0.0367 (7)	0.0375 (8)	0.0315 (7)	−0.0043 (6)	0.0021 (5)	−0.0010 (6)
C7	0.0535 (8)	0.0346 (8)	0.0363 (8)	−0.0053 (6)	0.0055 (6)	−0.0029 (6)
C8	0.0460 (8)	0.0331 (8)	0.0382 (8)	−0.0057 (6)	0.0051 (6)	0.0018 (6)
C9	0.0464 (8)	0.0421 (9)	0.0339 (8)	0.0000 (6)	0.0046 (6)	0.0049 (7)
C10	0.0456 (8)	0.0806 (13)	0.0365 (8)	0.0042 (8)	0.0143 (7)	0.0091 (9)
C11	0.0487 (9)	0.0662 (12)	0.0355 (8)	−0.0129 (8)	0.0052 (7)	0.0122 (8)
C12	0.0518 (9)	0.0470 (10)	0.0338 (8)	0.0015 (7)	0.0084 (6)	−0.0043 (7)
C13	0.0442 (8)	0.0543 (10)	0.0283 (7)	−0.0047 (7)	0.0041 (6)	0.0033 (7)
C14	0.0444 (8)	0.0380 (8)	0.0346 (8)	−0.0049 (6)	−0.0017 (6)	0.0030 (6)
C15	0.0410 (8)	0.0607 (11)	0.0358 (8)	−0.0132 (7)	−0.0063 (6)	0.0049 (8)
C16	0.0623 (10)	0.0507 (10)	0.0313 (8)	−0.0204 (8)	−0.0006 (7)	−0.0055 (7)
C17	0.0493 (8)	0.0454 (9)	0.0328 (8)	−0.0034 (7)	0.0079 (6)	−0.0024 (7)
C18	0.0427 (8)	0.0517 (9)	0.0265 (7)	−0.0136 (7)	−0.0017 (6)	0.0020 (7)
C19	0.0475 (9)	0.0934 (16)	0.0524 (11)	−0.0054 (10)	−0.0072 (8)	0.0120 (10)
C20	0.0559 (10)	0.0827 (15)	0.0455 (10)	0.0009 (9)	−0.0074 (8)	0.0076 (10)
C21	0.0448 (8)	0.0518 (10)	0.0501 (9)	−0.0117 (7)	0.0118 (7)	0.0008 (8)
C22	0.0569 (10)	0.0599 (11)	0.0510 (10)	−0.0133 (8)	0.0099 (8)	0.0112 (9)

Geometric parameters (Å, º) top

O1—C13	1.4210 (19)	C19—C20	1.492 (3)
O1—C19	1.417 (2)	C21—C22	1.503 (3)
O2—C13	1.4138 (17)	C1—H1	0.9800
O2—C20	1.414 (2)	C2—H2	0.9800
O3—C18	1.4165 (19)	C3—H3A	0.9700
O3—C21	1.404 (2)	C3—H3B	0.9700
O4—C18	1.4151 (17)	C4—H4A	0.9700
O4—C22	1.411 (2)	C4—H4B	0.9700
C1—C2	1.5722 (19)	C5—H5	0.9800
C1—C8	1.522 (2)	C6—H6	0.9800
C1—C9	1.554 (2)	C7—H7C	0.9700
C2—C3	1.536 (2)	C7—H7D	0.9700
C2—C12	1.563 (2)	C8—H8C	0.9700
C3—C4	1.539 (2)	C8—H8D	0.9700
C4—C5	1.523 (2)	C9—H9	0.9800
C5—C6	1.5721 (19)	C10—H10	0.9300
C5—C14	1.555 (2)	C11—H11	0.9300
C6—C7	1.534 (2)	C12—H12	0.9800
C6—C17	1.571 (2)	C14—H14	0.9800
C7—C8	1.533 (2)	C15—H15	0.9300
C9—C11	1.506 (2)	C16—H16	0.9300
C9—C13	1.545 (2)	C17—H17	0.9800
C10—C11	1.319 (3)	C19—H19G	0.9700
C10—C12	1.506 (2)	C19—H19H	0.9700
C12—C13	1.530 (2)	C20—H20E	0.9700
C14—C15	1.505 (2)	C20—H20F	0.9700
C14—C18	1.543 (2)	C21—H21A	0.9700
C15—C16	1.316 (3)	C21—H21B	0.9700
C16—C17	1.508 (2)	C22—H22C	0.9700
C17—C18	1.5232 (19)	C22—H22D	0.9700

C13—O1—C19	108.73 (13)	H3A—C3—H3B	107.00
C13—O2—C20	105.81 (12)	C3—C4—H4A	108.00
C18—O3—C21	109.41 (12)	C3—C4—H4B	108.00
C18—O4—C22	106.62 (12)	C5—C4—H4A	108.00
C2—C1—C8	116.40 (12)	C5—C4—H4B	108.00
C2—C1—C9	102.62 (11)	H4A—C4—H4B	107.00
C8—C1—C9	114.61 (11)	C4—C5—H5	107.00
C1—C2—C3	119.16 (11)	C6—C5—H5	107.00
C1—C2—C12	102.43 (12)	C14—C5—H5	107.00
C3—C2—C12	110.67 (12)	C5—C6—H6	108.00
C2—C3—C4	118.74 (12)	C7—C6—H6	108.00
C3—C4—C5	115.77 (12)	C17—C6—H6	108.00
C4—C5—C6	116.99 (11)	C6—C7—H7C	108.00
C4—C5—C14	114.35 (12)	C6—C7—H7D	108.00
C6—C5—C14	102.74 (11)	C8—C7—H7C	108.00
C5—C6—C7	119.51 (12)	C8—C7—H7D	108.00
C5—C6—C17	102.22 (11)	H7C—C7—H7D	107.00
C7—C6—C17	110.80 (11)	C1—C8—H8C	108.00
C6—C7—C8	118.79 (12)	C1—C8—H8D	109.00
C1—C8—C7	114.97 (12)	C7—C8—H8C	109.00
C1—C9—C11	108.64 (12)	C7—C8—H8D	109.00
C1—C9—C13	99.63 (11)	H8C—C8—H8D	108.00
C11—C9—C13	99.07 (12)	C1—C9—H9	116.00
C11—C10—C12	108.38 (15)	C11—C9—H9	116.00
C9—C11—C10	107.58 (15)	C13—C9—H9	116.00
C2—C12—C10	107.29 (13)	C11—C10—H10	126.00
C2—C12—C13	100.56 (12)	C12—C10—H10	126.00
C10—C12—C13	98.80 (15)	C9—C11—H11	126.00
O1—C13—O2	105.91 (12)	C10—C11—H11	126.00
O1—C13—C9	114.01 (13)	C2—C12—H12	116.00
O1—C13—C12	113.87 (15)	C10—C12—H12	116.00
O2—C13—C9	114.95 (15)	C13—C12—H12	116.00
O2—C13—C12	114.18 (13)	C5—C14—H14	116.00
C9—C13—C12	94.02 (12)	C15—C14—H14	116.00
C5—C14—C15	108.52 (12)	C18—C14—H14	116.00
C5—C14—C18	99.20 (11)	C14—C15—H15	126.00
C15—C14—C18	99.11 (11)	C16—C15—H15	126.00
C14—C15—C16	108.01 (14)	C15—C16—H16	126.00
C15—C16—C17	108.08 (15)	C17—C16—H16	126.00
C6—C17—C16	106.97 (12)	C6—C17—H17	116.00
C6—C17—C18	100.45 (11)	C16—C17—H17	116.00
C16—C17—C18	99.04 (13)	C18—C17—H17	116.00
O3—C18—O4	106.06 (12)	O1—C19—H19G	111.00
O3—C18—C14	113.46 (12)	O1—C19—H19H	111.00
O3—C18—C17	113.42 (12)	C20—C19—H19G	111.00
O4—C18—C14	116.03 (12)	C20—C19—H19H	111.00
O4—C18—C17	113.58 (12)	H19G—C19—H19H	109.00
C14—C18—C17	94.37 (11)	O2—C20—H20E	111.00
O1—C19—C20	104.67 (15)	O2—C20—H20F	111.00
O2—C20—C19	104.27 (15)	C19—C20—H20E	111.00
O3—C21—C22	104.87 (14)	C19—C20—H20F	111.00
O4—C22—C21	103.92 (15)	H20E—C20—H20F	109.00
C2—C1—H1	108.00	O3—C21—H21A	111.00
C8—C1—H1	108.00	O3—C21—H21B	111.00
C9—C1—H1	108.00	C22—C21—H21A	111.00
C1—C2—H2	108.00	C22—C21—H21B	111.00
C3—C2—H2	108.00	H21A—C21—H21B	109.00
C12—C2—H2	108.00	O4—C22—H22C	111.00
C2—C3—H3A	108.00	O4—C22—H22D	111.00
C2—C3—H3B	108.00	C21—C22—H22C	111.00
C4—C3—H3A	108.00	C21—C22—H22D	111.00
C4—C3—H3B	108.00	H22C—C22—H22D	109.00

C19—O1—C13—O2	−16.0 (2)	C5—C6—C7—C8	59.18 (18)
C19—O1—C13—C9	111.44 (16)	C17—C6—C7—C8	177.55 (13)
C19—O1—C13—C12	−142.24 (16)	C5—C6—C17—C16	68.32 (14)
C13—O1—C19—C20	−4.0 (2)	C5—C6—C17—C18	−34.58 (14)
C20—O2—C13—O1	30.52 (18)	C7—C6—C17—C16	−60.10 (16)
C20—O2—C13—C9	−96.31 (16)	C7—C6—C17—C18	−162.99 (12)
C20—O2—C13—C12	156.61 (15)	C6—C7—C8—C1	27.76 (19)
C13—O2—C20—C19	−32.55 (19)	C1—C9—C11—C10	70.25 (15)
C21—O3—C18—O4	−13.28 (16)	C13—C9—C11—C10	−33.20 (15)
C21—O3—C18—C14	115.23 (14)	C1—C9—C13—O1	58.67 (16)
C21—O3—C18—C17	−138.60 (14)	C1—C9—C13—O2	−178.77 (12)
C18—O3—C21—C22	−5.34 (18)	C1—C9—C13—C12	−59.72 (12)
C22—O4—C18—O3	27.73 (16)	C11—C9—C13—O1	169.48 (13)
C22—O4—C18—C14	−99.25 (15)	C11—C9—C13—O2	−67.95 (15)
C22—O4—C18—C17	152.96 (14)	C11—C9—C13—C12	51.10 (13)
C18—O4—C22—C21	−30.43 (17)	C12—C10—C11—C9	−0.71 (17)
C8—C1—C2—C3	−5.80 (18)	C11—C10—C12—C2	−69.33 (17)
C8—C1—C2—C12	−128.27 (13)	C11—C10—C12—C13	34.70 (16)
C9—C1—C2—C3	120.19 (13)	C2—C12—C13—O1	−60.17 (16)
C9—C1—C2—C12	−2.28 (14)	C2—C12—C13—O2	178.01 (14)
C2—C1—C8—C7	−85.21 (15)	C2—C12—C13—C9	58.33 (13)
C9—C1—C8—C7	155.07 (12)	C10—C12—C13—O1	−169.73 (13)
C2—C1—C9—C11	−64.62 (14)	C10—C12—C13—O2	68.45 (17)
C2—C1—C9—C13	38.44 (13)	C10—C12—C13—C9	−51.23 (13)
C8—C1—C9—C11	62.51 (16)	C5—C14—C15—C16	70.53 (16)
C8—C1—C9—C13	165.58 (12)	C18—C14—C15—C16	−32.44 (15)
C1—C2—C3—C4	60.36 (17)	C5—C14—C18—O3	57.69 (14)
C12—C2—C3—C4	178.65 (13)	C5—C14—C18—O4	−179.12 (11)
C1—C2—C12—C10	67.63 (15)	C5—C14—C18—C17	−60.19 (12)
C1—C2—C12—C13	−35.14 (15)	C15—C14—C18—O3	168.29 (12)
C3—C2—C12—C10	−60.42 (17)	C15—C14—C18—O4	−68.52 (15)
C3—C2—C12—C13	−163.20 (12)	C15—C14—C18—C17	50.41 (12)
C2—C3—C4—C5	25.27 (17)	C14—C15—C16—C17	−1.07 (17)
C3—C4—C5—C6	−82.83 (15)	C15—C16—C17—C6	−69.25 (16)
C3—C4—C5—C14	157.02 (11)	C15—C16—C17—C18	34.67 (16)
C4—C5—C6—C7	−6.45 (18)	C6—C17—C18—O3	−59.54 (15)
C4—C5—C6—C17	−129.14 (13)	C6—C17—C18—O4	179.28 (12)
C14—C5—C6—C7	119.68 (13)	C6—C17—C18—C14	58.38 (12)
C14—C5—C6—C17	−3.01 (13)	C16—C17—C18—O3	−168.80 (12)
C4—C5—C14—C15	63.85 (15)	C16—C17—C18—O4	70.02 (15)
C4—C5—C14—C18	166.77 (11)	C16—C17—C18—C14	−50.88 (12)
C6—C5—C14—C15	−63.96 (14)	O1—C19—C20—O2	22.4 (2)
C6—C5—C14—C18	38.95 (12)	O3—C21—C22—O4	21.88 (18)

Experimental details

Crystal data
Chemical formula	C₂₂H₂₈O₄
M_r	356.44
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	295
a, b, c (Å)	11.4167 (11), 6.7354 (7), 24.185 (2)
β (°)	103.521 (9)
V (Å³)	1808.2 (3)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	0.71
Crystal size (mm)	0.35 × 0.20 × 0.20

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	8422, 3248, 2693
R_int	0.045
(sin θ/λ)_max (Å⁻¹)	0.599

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.106, 1.05
No. of reflections	3248
No. of parameters	236
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.19

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae, et al., 2006), WinGX (Farrugia, 1999).

Acknowledgements

This work was supported in part by funds provided by the University of North Carolina at Charlotte. Support for Research Experience for Undergraduates (REU) participant RMK was provided by the National Science Foundation, award number CHE-0851797. Many helpful discussions with T. Blake Monroe are gratefully acknowledged.

References

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