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Acta Cryst. (2009). E65, o243    [ doi:10.1107/S1600536808044309 ]

(R)-Di-tert-butyl 1,1'-binaphthyl-2,2'-dicarboxylate

M. Thoss, R. W. Seidel and M. Feigel

Abstract top

The crystal structure of the title compound, C30H30O4, comprises two crystallographically independent half-molecules which are completed by crystallographic twofold symmetry. The dihedral angles between the naphthalene ring planes are 85.83 (3) and 83.69 (3)° for the two molecules. The atoms of the tert-butyl group of one molecule are disordered over two sets of sites with occupancies of 0.60:0.40. The crystal packing is achieved via [pi]-[pi] stacking interactions between the naphthyl groups of adjacent molecules, with a separation of 3.790 (1) Å between the centroids of the rings.

Comment top

For the (S)-form of 2,2'-dihydroxy-1,1'-binaphthyl (BINOL) was reported that during the reaction with equimolar amounts of pivaloyl chloride the formation of the corresponding 2,2'-pivalate is almost completely suppressed due to the steric hindrance rising from the bulky pivaloyl group (Hocke & Uozumi, 2002, 2003). However, we obtained the (R)-form of the 2,2'-dipivalate under forced conditions (see below) and determined its structure by X-ray crystallography.

An ORTEP diagram of the title compound is given in Fig. 1. The structure consists of two crystallographic independent molecules, which are located both on crystallographic twofold axes. The molecules belong to the point group C2 and exhibit axial chirality. Molecular geometry parameters are within expected ranges. The tertiary butyl groups of one molecule show rotational disorder over two sites with occupancies of 0.60:0.40. The dihedral angles between the mean planes of the naphthyl groups are 85.83 (3) and 83.69 (3)° for the non-disordered and the disordered molecule, respectively. In comparison, an angle of 78.35 (5)° has been reported for the parent (R)-BINOL (Mori et al., 1993). The molecules interact via π–π stacking of the naphthyl groups of adjacent molecules with a separation of 3.790 (1) Å between the centroids of the rings C5–C10 and C15–C20. The mean interplanar distance is 3.59 Å and the offset is about 18.9°.

Related literature top

For the crystal structure of the parent (R)-2,2'-dihydroxy-1,1'-binaphthyl (BINOL), see: Mori et al. (1993). For the synthesis of the corresponding monopivalate of (S)-BINOL, see: Hocke & Uozumi (2002, 2003). For applications of BINOL-derived chiral ligands, see: Shibasaki & Matsunaga (2006).

Experimental top

To a solution of (R)-BINOL (4.34 mmol, 1.26 g) and triethylamine (26.7 mmol, 3.7 ml) in acetonitrile (13 ml) was added pivaloyl chloride (8.94 mmol, 1.1 ml) dropwise at 0°C. Subsequent, the reaction mixture was stirred over night and allowed to warm up to room temperature. Diethyl ether was added and the mixture was washed with aqueous 1 N HCl, saturated aqueous NaHCO3 and brine three times, respectively. The organic phase was dried over MgSO4 and the solvent was removed under reduced pressure. The crude product was purified by column chromatography over silica gel using ethyl acetate–n-hexane (1:6) as eluent. Yield: 1.15 g (58%). Single crystals of the title compound suitable for X-ray diffraction were grown from ethyl acetate–n-hexane (1:6) by slow evaporation of the solvent.

[α]25D + 88.94 (c 1.88, THF); 1H NMR (200 MHz, CDCl3) δ 7.30–7.37 (m, 4 H), 7.41–7.54 (m, 4 H), 7.96 (d, J = 8.17 Hz, 2 H), 8.01 (d, J = 8.93 Hz, 2 H); 13C NMR (200 MHz, CDCl3) δ 26.33, 38.61, 121.89, 123.62, 125.54, 126.03, 126.56, 127.82, 129.16, 131.44, 133.43, 146.94, 176.31; Anal. calcd for C30H30O4: C 79.27; H 6.65. Found: C 79.33, H 6.14; MS(FAB): m/z 455.3 [M+H]+.

Refinement top

The crystal structure was refined by full-matrix least-squares refinement on F2. Due to the absence of significant anomalous scattering effects, Friedel pairs have been merged. Anisotropic displacement parameters were introduced for all non-hydrogen atoms. Similar distance restraints were applied to the 1,2- and 1,3-distances of the disordered tertiary butyl group, respectively. The opposite C atoms of the disordered group were refined with equivalent anisotropic displacement parameters, respectively. H atoms were placed at geometrically calculated positions and refined with Uiso 1.2 times (1.5 for methyl groups) of their parent atoms and allowing to ride on them. The initial torsion angles of the methyl groups of the non-disordered tertiary butyl group were determined via a difference Fourier analysis. For the disordered tertiary butyl group those were calculated to be staggered.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. ORTEP diagram of the title compound. Displacement ellipsoids are drawn at the 50% probability level. H atoms are omitted for clarity. Symmetry codes: (i) -x + 2, y, -z + 1/2, (ii) x, -y + 1, -z + 1.
(R)-Di-tert-butyl 1,1'-binaphthyl-2,2'-dicarboxylate top
Crystal data top
C30H30O4F(000) = 1936
Mr = 454.54Dx = 1.211 Mg m−3
Orthorhombic, C2221Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2c 2Cell parameters from 8276 reflections
a = 9.6972 (4) Åθ = 2.6–30.3°
b = 25.8488 (13) ŵ = 0.08 mm−1
c = 19.9000 (9) ÅT = 108 K
V = 4988.2 (4) Å3Prism, colourless
Z = 80.37 × 0.21 × 0.18 mm
Data collection top
Oxford Diffraction Sapphire2 CCD
diffractometer		3175 independent reflections
Radiation source: Enhance (Mo) X-ray Source2423 reflections with I > 2σ(I)
graphiteRint = 0.043
Detector resolution: 8.4171 pixels mm-1θmax = 27.5°, θmin = 3.3°
ω scansh = −12→12
Absorption correction: multi-scan
(ABSPACK in CrysAlis RED; Oxford Diffraction, 2008)		k = −31→33
Tmin = 0.972, Tmax = 0.984l = −25→25
33031 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.072H-atom parameters constrained
S = 0.89 w = 1/[σ2(Fo2) + (0.0436P)2]
where P = (Fo2 + 2Fc2)/3
3175 reflections(Δ/σ)max < 0.001
320 parametersΔρmax = 0.18 e Å−3
30 restraintsΔρmin = −0.16 e Å−3
Crystal data top
C30H30O4V = 4988.2 (4) Å3
Mr = 454.54Z = 8
Orthorhombic, C2221Mo Kα radiation
a = 9.6972 (4) ŵ = 0.08 mm−1
b = 25.8488 (13) ÅT = 108 K
c = 19.9000 (9) Å0.37 × 0.21 × 0.18 mm
Data collection top
Oxford Diffraction Sapphire2 CCD
diffractometer		3175 independent reflections
Absorption correction: multi-scan
(ABSPACK in CrysAlis RED; Oxford Diffraction, 2008)		2423 reflections with I > 2σ(I)
Tmin = 0.972, Tmax = 0.984Rint = 0.043
33031 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.033H-atom parameters constrained
wR(F2) = 0.072Δρmax = 0.18 e Å−3
S = 0.89Δρmin = −0.16 e Å−3
3175 reflectionsAbsolute structure: ?
320 parametersFlack parameter: ?
30 restraintsRogers parameter: ?
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
xyzUiso*/UeqOcc. (<1)
O10.63715 (16)0.30623 (6)0.17450 (7)0.0318 (4)
O20.82275 (13)0.26221 (5)0.21109 (6)0.0232 (3)
C210.7200 (2)0.27252 (8)0.16612 (10)0.0218 (4)
C10.94407 (19)0.32395 (7)0.27619 (9)0.0199 (4)
C20.8298 (2)0.29383 (7)0.26837 (9)0.0208 (4)
C30.7240 (2)0.29102 (8)0.31619 (10)0.0252 (5)
H30.64660.26920.30900.030*
C40.7338 (2)0.31991 (8)0.37300 (10)0.0260 (5)
H40.66300.31790.40590.031*
C50.8550 (2)0.38512 (8)0.44130 (10)0.0289 (5)
H50.78390.38370.47410.035*
C60.9627 (2)0.41821 (9)0.45025 (10)0.0326 (5)
H60.96560.44000.48870.039*
C71.0696 (2)0.42013 (9)0.40251 (11)0.0321 (5)
H71.14490.44310.40910.039*
C81.0663 (2)0.38929 (8)0.34679 (10)0.0257 (5)
H81.13980.39080.31530.031*
C90.9546 (2)0.35511 (8)0.33540 (10)0.0215 (4)
C100.8474 (2)0.35282 (8)0.38388 (9)0.0224 (4)
C220.7294 (2)0.23684 (8)0.10603 (9)0.0245 (5)
C230.7295 (2)0.18046 (8)0.13026 (11)0.0318 (5)
H23A0.81120.17430.15810.048*
H23B0.73130.15720.09130.048*
H23C0.64620.17390.15680.048*
C240.8636 (2)0.24911 (9)0.06858 (11)0.0334 (5)
H24A0.86350.28550.05480.050*
H24B0.87080.22700.02870.050*
H24C0.94240.24260.09830.050*
C250.6065 (2)0.24659 (9)0.06012 (11)0.0352 (5)
H25A0.52080.24000.08480.053*
H25B0.61160.22340.02120.053*
H25C0.60790.28260.04480.053*
O110.49149 (19)0.36700 (6)0.55217 (8)0.0481 (5)
O120.35449 (14)0.43270 (5)0.52184 (7)0.0263 (3)
C110.53052 (19)0.48267 (7)0.46989 (9)0.0210 (4)
C120.4422 (2)0.44153 (8)0.46680 (10)0.0224 (4)
C130.4321 (2)0.40866 (8)0.41121 (10)0.0263 (5)
H130.36780.38090.41110.032*
C140.5153 (2)0.41686 (8)0.35726 (10)0.0270 (5)
H140.50770.39500.31900.032*
C150.7071 (2)0.46426 (9)0.30391 (10)0.0324 (5)
H150.70280.44190.26600.039*
C160.8038 (2)0.50233 (9)0.30582 (11)0.0351 (6)
H160.86800.50580.27000.042*
C170.8088 (2)0.53657 (9)0.36088 (11)0.0344 (5)
H170.87540.56350.36160.041*
C180.7185 (2)0.53139 (8)0.41322 (11)0.0267 (5)
H180.72220.55510.44960.032*
C190.6200 (2)0.49123 (7)0.41380 (9)0.0215 (4)
C200.6130 (2)0.45738 (8)0.35732 (9)0.0244 (5)
C310.3931 (2)0.39330 (9)0.56367 (10)0.0292 (5)
C320.2992 (3)0.38865 (9)0.62358 (12)0.0388 (6)
C330.3695 (5)0.3673 (3)0.6811 (2)0.0810 (18)0.601 (3)
H33A0.30490.36460.71880.122*0.601 (3)
H33B0.44640.38990.69360.122*0.601 (3)
H33C0.40480.33280.66990.122*0.601 (3)
C340.2190 (6)0.4386 (2)0.6369 (3)0.0647 (13)0.601 (3)
H34A0.16200.44690.59770.097*0.601 (3)
H34B0.28400.46700.64520.097*0.601 (3)
H34C0.15980.43400.67640.097*0.601 (3)
C350.1845 (5)0.34794 (19)0.5970 (2)0.0549 (10)0.601 (3)
H35A0.13640.36260.55810.082*0.601 (3)
H35B0.11800.34100.63290.082*0.601 (3)
H35C0.22990.31560.58380.082*0.601 (3)
C33'0.1614 (7)0.4053 (5)0.6191 (4)0.0810 (18)0.399 (3)
H33D0.11510.39960.66220.122*0.399 (3)
H33E0.11390.38580.58380.122*0.399 (3)
H33F0.15930.44230.60810.122*0.399 (3)
C34'0.3208 (10)0.3352 (3)0.6572 (4)0.0647 (13)0.399 (3)
H34D0.41940.32700.65820.097*0.399 (3)
H34E0.27180.30860.63140.097*0.399 (3)
H34F0.28480.33610.70320.097*0.399 (3)
C35'0.3811 (7)0.4262 (3)0.6770 (3)0.0549 (10)0.399 (3)
H35D0.47730.41500.68070.082*0.399 (3)
H35E0.33680.42390.72120.082*0.399 (3)
H35F0.37790.46200.66110.082*0.399 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0349 (8)0.0306 (8)0.0298 (8)0.0125 (7)−0.0038 (7)−0.0014 (6)
O20.0208 (7)0.0249 (8)0.0238 (7)0.0003 (6)−0.0012 (6)−0.0050 (6)
C210.0191 (10)0.0226 (11)0.0238 (10)−0.0024 (9)0.0019 (8)0.0038 (9)
C10.0190 (10)0.0223 (11)0.0185 (9)0.0035 (8)0.0001 (8)0.0034 (8)
C20.0204 (10)0.0224 (10)0.0197 (10)0.0020 (8)−0.0021 (8)−0.0008 (8)
C30.0206 (10)0.0265 (12)0.0284 (11)−0.0013 (9)0.0030 (9)0.0020 (9)
C40.0259 (11)0.0295 (12)0.0228 (10)0.0040 (10)0.0086 (9)0.0058 (9)
C50.0333 (12)0.0321 (12)0.0213 (10)0.0091 (10)0.0022 (10)0.0004 (9)
C60.0387 (13)0.0331 (13)0.0260 (11)0.0116 (11)−0.0052 (10)−0.0085 (10)
C70.0274 (11)0.0322 (13)0.0368 (12)0.0021 (10)−0.0070 (10)−0.0072 (10)
C80.0223 (11)0.0290 (12)0.0258 (11)0.0017 (9)0.0002 (9)−0.0009 (9)
C90.0218 (10)0.0225 (11)0.0201 (10)0.0040 (8)−0.0015 (8)0.0012 (8)
C100.0253 (11)0.0223 (11)0.0195 (10)0.0055 (9)0.0000 (8)0.0025 (8)
C220.0252 (11)0.0251 (12)0.0232 (10)0.0012 (9)0.0010 (9)−0.0014 (8)
C230.0377 (13)0.0269 (12)0.0307 (11)−0.0019 (10)0.0000 (10)−0.0033 (9)
C240.0345 (12)0.0383 (13)0.0275 (11)0.0004 (11)0.0090 (10)−0.0041 (9)
C250.0387 (13)0.0371 (14)0.0297 (12)0.0043 (11)−0.0083 (10)−0.0058 (10)
O110.0449 (10)0.0526 (11)0.0469 (10)0.0205 (9)0.0125 (9)0.0172 (9)
O120.0248 (8)0.0240 (8)0.0302 (7)0.0000 (6)0.0037 (6)0.0000 (6)
C110.0211 (10)0.0209 (11)0.0211 (10)0.0035 (8)−0.0023 (8)−0.0003 (8)
C120.0194 (10)0.0217 (11)0.0260 (11)0.0037 (8)0.0002 (9)0.0017 (8)
C130.0256 (11)0.0216 (11)0.0319 (11)−0.0002 (9)−0.0062 (9)−0.0026 (9)
C140.0311 (12)0.0272 (12)0.0227 (10)0.0051 (10)−0.0078 (9)−0.0051 (9)
C150.0398 (13)0.0362 (13)0.0214 (11)0.0079 (11)0.0009 (10)−0.0022 (10)
C160.0327 (12)0.0445 (14)0.0282 (12)0.0059 (11)0.0101 (10)0.0055 (10)
C170.0314 (12)0.0330 (13)0.0388 (13)−0.0035 (10)0.0059 (11)0.0024 (11)
C180.0293 (11)0.0238 (11)0.0271 (11)−0.0007 (10)0.0013 (9)−0.0010 (9)
C190.0227 (10)0.0218 (11)0.0201 (10)0.0044 (9)−0.0015 (9)0.0008 (8)
C200.0277 (11)0.0248 (11)0.0208 (10)0.0062 (9)−0.0030 (9)−0.0001 (9)
C310.0285 (12)0.0292 (12)0.0298 (11)−0.0034 (10)−0.0030 (10)−0.0011 (10)
C320.0392 (13)0.0397 (14)0.0377 (12)−0.0006 (12)0.0118 (11)0.0038 (11)
C330.045 (2)0.161 (6)0.037 (2)0.008 (3)0.006 (2)0.036 (3)
C340.072 (3)0.063 (3)0.060 (3)0.002 (2)0.034 (3)−0.003 (2)
C350.055 (2)0.062 (3)0.048 (2)−0.018 (2)0.012 (2)−0.0006 (19)
C33'0.045 (2)0.161 (6)0.037 (2)0.008 (3)0.006 (2)0.036 (3)
C34'0.072 (3)0.063 (3)0.060 (3)0.002 (2)0.034 (3)−0.003 (2)
C35'0.055 (2)0.062 (3)0.048 (2)−0.018 (2)0.012 (2)−0.0006 (19)
Geometric parameters (Å, °) top
O1—C211.197 (2)C12—C131.398 (3)
O2—C211.365 (2)C13—C141.360 (3)
O2—C21.404 (2)C13—H130.9500
C21—C221.513 (3)C14—C201.412 (3)
C1—C21.363 (3)C14—H140.9500
C1—C91.431 (3)C15—C161.360 (3)
C1—C1i1.504 (4)C15—C201.412 (3)
C2—C31.401 (3)C15—H150.9500
C3—C41.358 (3)C16—C171.409 (3)
C3—H30.9500C16—H160.9500
C4—C101.408 (3)C17—C181.367 (3)
C4—H40.9500C17—H170.9500
C5—C61.361 (3)C18—C191.411 (3)
C5—C101.417 (3)C18—H180.9500
C5—H50.9500C19—C201.426 (3)
C6—C71.407 (3)C31—C321.505 (3)
C6—H60.9500C32—C33'1.407 (7)
C7—C81.366 (3)C32—C331.441 (5)
C7—H70.9500C32—C341.531 (5)
C8—C91.417 (3)C32—C34'1.549 (7)
C8—H80.9500C32—C351.620 (5)
C9—C101.419 (3)C32—C35'1.644 (6)
C22—C251.522 (3)C33—H33A0.9800
C22—C241.533 (3)C33—H33B0.9800
C22—C231.535 (3)C33—H33C0.9800
C23—H23A0.9800C34—H34A0.9800
C23—H23B0.9800C34—H34B0.9800
C23—H23C0.9800C34—H34C0.9800
C24—H24A0.9800C35—H35A0.9800
C24—H24B0.9800C35—H35B0.9800
C24—H24C0.9800C35—H35C0.9800
C25—H25A0.9800C33'—H33D0.9800
C25—H25B0.9800C33'—H33E0.9800
C25—H25C0.9800C33'—H33F0.9800
O11—C311.194 (3)C34'—H34D0.9800
O12—C311.368 (2)C34'—H34E0.9800
O12—C121.405 (2)C34'—H34F0.9800
C11—C121.367 (3)C35'—H35D0.9800
C11—C191.431 (3)C35'—H35E0.9800
C11—C11ii1.496 (4)C35'—H35F0.9800
C21—O2—C2117.00 (15)C15—C16—H16120.0
O1—C21—O2122.72 (18)C17—C16—H16120.0
O1—C21—C22126.45 (18)C18—C17—C16120.6 (2)
O2—C21—C22110.82 (16)C18—C17—H17119.7
C2—C1—C9118.25 (17)C16—C17—H17119.7
C2—C1—C1i120.46 (17)C17—C18—C19120.8 (2)
C9—C1—C1i121.29 (17)C17—C18—H18119.6
C1—C2—C3123.17 (18)C19—C18—H18119.6
C1—C2—O2117.69 (17)C18—C19—C20118.49 (18)
C3—C2—O2119.05 (17)C18—C19—C11122.06 (17)
C4—C3—C2119.06 (19)C20—C19—C11119.42 (18)
C4—C3—H3120.5C14—C20—C15121.75 (18)
C2—C3—H3120.5C14—C20—C19119.18 (18)
C3—C4—C10120.98 (19)C15—C20—C19119.03 (19)
C3—C4—H4119.5O11—C31—O12121.7 (2)
C10—C4—H4119.5O11—C31—C32126.1 (2)
C6—C5—C10121.0 (2)O12—C31—C32112.11 (19)
C6—C5—H5119.5C33'—C32—C33128.1 (4)
C10—C5—H5119.5C33'—C32—C31120.0 (4)
C5—C6—C7119.94 (19)C33—C32—C31111.9 (3)
C5—C6—H6120.0C33'—C32—C3443.1 (5)
C7—C6—H6120.0C33—C32—C34115.2 (4)
C8—C7—C6120.7 (2)C31—C32—C34112.2 (3)
C8—C7—H7119.7C33'—C32—C34'115.4 (6)
C6—C7—H7119.7C33—C32—C34'41.6 (4)
C7—C8—C9120.79 (19)C31—C32—C34'109.4 (3)
C7—C8—H8119.6C34—C32—C34'138.3 (4)
C9—C8—H8119.6C33'—C32—C3561.7 (5)
C8—C9—C10118.51 (17)C33—C32—C35109.5 (4)
C8—C9—C1122.49 (17)C31—C32—C35102.0 (2)
C10—C9—C1118.97 (17)C34—C32—C35104.8 (3)
C4—C10—C5121.36 (19)C34'—C32—C3569.8 (4)
C4—C10—C9119.55 (17)C33'—C32—C35'108.6 (6)
C5—C10—C9119.05 (19)C33—C32—C35'59.0 (4)
C21—C22—C25109.06 (16)C31—C32—C35'100.0 (3)
C21—C22—C24107.99 (16)C34—C32—C35'68.6 (4)
C25—C22—C24109.79 (16)C34'—C32—C35'100.5 (5)
C21—C22—C23109.30 (16)C35—C32—C35'157.8 (3)
C25—C22—C23110.28 (18)C32—C33—H33A109.5
C24—C22—C23110.37 (18)C32—C33—H33B109.5
C22—C23—H23A109.5H33A—C33—H33B109.5
C22—C23—H23B109.5C32—C33—H33C109.5
H23A—C23—H23B109.5H33A—C33—H33C109.5
C22—C23—H23C109.5H33B—C33—H33C109.5
H23A—C23—H23C109.5C32—C34—H34A109.5
H23B—C23—H23C109.5C32—C34—H34B109.5
C22—C24—H24A109.5H34A—C34—H34B109.5
C22—C24—H24B109.5C32—C34—H34C109.5
H24A—C24—H24B109.5H34A—C34—H34C109.5
C22—C24—H24C109.5H34B—C34—H34C109.5
H24A—C24—H24C109.5C32—C35—H35A109.5
H24B—C24—H24C109.5C32—C35—H35B109.5
C22—C25—H25A109.5H35A—C35—H35B109.5
C22—C25—H25B109.5C32—C35—H35C109.5
H25A—C25—H25B109.5H35A—C35—H35C109.5
C22—C25—H25C109.5H35B—C35—H35C109.5
H25A—C25—H25C109.5C32—C33'—H33D109.5
H25B—C25—H25C109.5C32—C33'—H33E109.5
C31—O12—C12115.44 (15)H33D—C33'—H33E109.5
C12—C11—C19117.72 (17)C32—C33'—H33F109.5
C12—C11—C11ii120.13 (17)H33D—C33'—H33F109.5
C19—C11—C11ii122.14 (17)H33E—C33'—H33F109.5
C11—C12—C13123.51 (19)C32—C34'—H34D109.5
C11—C12—O12118.07 (17)C32—C34'—H34E109.5
C13—C12—O12118.40 (18)H34D—C34'—H34E109.5
C14—C13—C12119.23 (19)C32—C34'—H34F109.5
C14—C13—H13120.4H34D—C34'—H34F109.5
C12—C13—H13120.4H34E—C34'—H34F109.5
C13—C14—C20120.87 (18)C32—C35'—H35D109.5
C13—C14—H14119.6C32—C35'—H35E109.5
C20—C14—H14119.6H35D—C35'—H35E109.5
C16—C15—C20121.1 (2)C32—C35'—H35F109.5
C16—C15—H15119.5H35D—C35'—H35F109.5
C20—C15—H15119.5H35E—C35'—H35F109.5
C15—C16—C17120.0 (2)
Symmetry codes: (i) −x+2, y, −z+1/2; (ii) x, −y+1, −z+1.
Acknowledgements top

The authors thank Dr Christian Gemel for providing diffractometer time. MT thanks the Degussa Foundation and Evonik Industries AG for a PhD fellowship. RWS thanks Professor William S. Sheldrick for generous support.

references
References top

Brandenburg, K. (2008). DIAMOND. Crystal Impact GbR, Bonn, Germany.

Hocke, H. & Uozumi, Y. (2002). Synlett, pp. 2049–2053.

Hocke, H. & Uozumi, Y. (2003). Tetrahedron, 59, 619–630.

Mori, K., Masuda, Y. & Kashino, S. (1993). Acta Cryst. C49, 1224–1227.

Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Shibasaki, M. & Matsunaga, S. (2006). Chem. Soc. Rev. 35, 269–279.