(R)-Di-tert-butyl 1,1'-binaphthyl-2,2'-dicarboxyl-ate.

The crystal structure of the title compound, C(30)H(30)O(4), comprises two crystallographically independent half-mol-ecules 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 mol-ecule are disordered over two sets of sites with occupancies of 0.60:0.40. The crystal packing is achieved via π-π stacking inter-actions between the naphthyl groups of adjacent mol-ecules, with a separation of 3.790 (1) Å between the centroids of the rings.

Related literature

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

Crystal data

C30H30O4

M = 454.54

Orthorhombic,

a = 9.6972 (4) Å

b = 25.8488 (13) Å

c = 19.9000 (9) Å

V = 4988.2 (4) Å3

Z = 8

Mo Kα radiation

μ = 0.08 mm−1

T = 108 (2) K

0.37 × 0.21 × 0.18 mm

Data collection

Oxford Diffraction Sapphire2 CCD diffractometer

Absorption correction: multi-scan (ABSPACK in CrysAlis RED; Oxford Diffraction, 2008 ▶) T min = 0.972, T max = 0.984

33031 measured reflections

3175 independent reflections

2423 reflections with I > 2σ(I)

R int = 0.043

Refinement

R[F 2 > 2σ(F 2)] = 0.033

wR(F 2) = 0.072

S = 0.89

3175 reflections

320 parameters

30 restraints

H-atom parameters constrained

Δρmax = 0.18 e Å−3

Δρmin = −0.16 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 ▶); data reduction: CrysAlis RED; 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.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808044309/dn2418sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808044309/dn2418Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C30H30O4	F(000) = 1936
Mr = 454.54	Dx = 1.211 Mg m−3
Orthorhombic, C2221	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2c 2	Cell parameters from 8276 reflections
a = 9.6972 (4) Å	θ = 2.6–30.3°
b = 25.8488 (13) Å	µ = 0.08 mm−1
c = 19.9000 (9) Å	T = 108 K
V = 4988.2 (4) Å3	Prism, colourless
Z = 8	0.37 × 0.21 × 0.18 mm

Oxford Diffraction Sapphire2 CCD diffractometer	3175 independent reflections
Radiation source: Enhance (Mo) X-ray Source	2423 reflections with I > 2σ(I)
graphite	Rint = 0.043
Detector resolution: 8.4171 pixels mm-1	θmax = 27.5°, θmin = 3.3°
ω scans	h = −12→12
Absorption correction: multi-scan (ABSPACK in CrysAlis RED; Oxford Diffraction, 2008)	k = −31→33
Tmin = 0.972, Tmax = 0.984	l = −25→25
33031 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.072	H-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 parameters	Δρmax = 0.18 e Å−3
30 restraints	Δρmin = −0.16 e Å−3

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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.63715 (16)	0.30623 (6)	0.17450 (7)	0.0318 (4)
O2	0.82275 (13)	0.26221 (5)	0.21109 (6)	0.0232 (3)
C21	0.7200 (2)	0.27252 (8)	0.16612 (10)	0.0218 (4)
C1	0.94407 (19)	0.32395 (7)	0.27619 (9)	0.0199 (4)
C2	0.8298 (2)	0.29383 (7)	0.26837 (9)	0.0208 (4)
C3	0.7240 (2)	0.29102 (8)	0.31619 (10)	0.0252 (5)
H3	0.6466	0.2692	0.3090	0.030*
C4	0.7338 (2)	0.31991 (8)	0.37300 (10)	0.0260 (5)
H4	0.6630	0.3179	0.4059	0.031*
C5	0.8550 (2)	0.38512 (8)	0.44130 (10)	0.0289 (5)
H5	0.7839	0.3837	0.4741	0.035*
C6	0.9627 (2)	0.41821 (9)	0.45025 (10)	0.0326 (5)
H6	0.9656	0.4400	0.4887	0.039*
C7	1.0696 (2)	0.42013 (9)	0.40251 (11)	0.0321 (5)
H7	1.1449	0.4431	0.4091	0.039*
C8	1.0663 (2)	0.38929 (8)	0.34679 (10)	0.0257 (5)
H8	1.1398	0.3908	0.3153	0.031*
C9	0.9546 (2)	0.35511 (8)	0.33540 (10)	0.0215 (4)
C10	0.8474 (2)	0.35282 (8)	0.38388 (9)	0.0224 (4)
C22	0.7294 (2)	0.23684 (8)	0.10603 (9)	0.0245 (5)
C23	0.7295 (2)	0.18046 (8)	0.13026 (11)	0.0318 (5)
H23A	0.8112	0.1743	0.1581	0.048*
H23B	0.7313	0.1572	0.0913	0.048*
H23C	0.6462	0.1739	0.1568	0.048*
C24	0.8636 (2)	0.24911 (9)	0.06858 (11)	0.0334 (5)
H24A	0.8635	0.2855	0.0548	0.050*
H24B	0.8708	0.2270	0.0287	0.050*
H24C	0.9424	0.2426	0.0983	0.050*
C25	0.6065 (2)	0.24659 (9)	0.06012 (11)	0.0352 (5)
H25A	0.5208	0.2400	0.0848	0.053*
H25B	0.6116	0.2234	0.0212	0.053*
H25C	0.6079	0.2826	0.0448	0.053*
O11	0.49149 (19)	0.36700 (6)	0.55217 (8)	0.0481 (5)
O12	0.35449 (14)	0.43270 (5)	0.52184 (7)	0.0263 (3)
C11	0.53052 (19)	0.48267 (7)	0.46989 (9)	0.0210 (4)
C12	0.4422 (2)	0.44153 (8)	0.46680 (10)	0.0224 (4)
C13	0.4321 (2)	0.40866 (8)	0.41121 (10)	0.0263 (5)
H13	0.3678	0.3809	0.4111	0.032*
C14	0.5153 (2)	0.41686 (8)	0.35726 (10)	0.0270 (5)
H14	0.5077	0.3950	0.3190	0.032*
C15	0.7071 (2)	0.46426 (9)	0.30391 (10)	0.0324 (5)
H15	0.7028	0.4419	0.2660	0.039*
C16	0.8038 (2)	0.50233 (9)	0.30582 (11)	0.0351 (6)
H16	0.8680	0.5058	0.2700	0.042*
C17	0.8088 (2)	0.53657 (9)	0.36088 (11)	0.0344 (5)
H17	0.8754	0.5635	0.3616	0.041*
C18	0.7185 (2)	0.53139 (8)	0.41322 (11)	0.0267 (5)
H18	0.7222	0.5551	0.4496	0.032*
C19	0.6200 (2)	0.49123 (7)	0.41380 (9)	0.0215 (4)
C20	0.6130 (2)	0.45738 (8)	0.35732 (9)	0.0244 (5)
C31	0.3931 (2)	0.39330 (9)	0.56367 (10)	0.0292 (5)
C32	0.2992 (3)	0.38865 (9)	0.62358 (12)	0.0388 (6)
C33	0.3695 (5)	0.3673 (3)	0.6811 (2)	0.0810 (18)	0.601 (3)
H33A	0.3049	0.3646	0.7188	0.122*	0.601 (3)
H33B	0.4464	0.3899	0.6936	0.122*	0.601 (3)
H33C	0.4048	0.3328	0.6699	0.122*	0.601 (3)
C34	0.2190 (6)	0.4386 (2)	0.6369 (3)	0.0647 (13)	0.601 (3)
H34A	0.1620	0.4469	0.5977	0.097*	0.601 (3)
H34B	0.2840	0.4670	0.6452	0.097*	0.601 (3)
H34C	0.1598	0.4340	0.6764	0.097*	0.601 (3)
C35	0.1845 (5)	0.34794 (19)	0.5970 (2)	0.0549 (10)	0.601 (3)
H35A	0.1364	0.3626	0.5581	0.082*	0.601 (3)
H35B	0.1180	0.3410	0.6329	0.082*	0.601 (3)
H35C	0.2299	0.3156	0.5838	0.082*	0.601 (3)
C33'	0.1614 (7)	0.4053 (5)	0.6191 (4)	0.0810 (18)	0.399 (3)
H33D	0.1151	0.3996	0.6622	0.122*	0.399 (3)
H33E	0.1139	0.3858	0.5838	0.122*	0.399 (3)
H33F	0.1593	0.4423	0.6081	0.122*	0.399 (3)
C34'	0.3208 (10)	0.3352 (3)	0.6572 (4)	0.0647 (13)	0.399 (3)
H34D	0.4194	0.3270	0.6582	0.097*	0.399 (3)
H34E	0.2718	0.3086	0.6314	0.097*	0.399 (3)
H34F	0.2848	0.3361	0.7032	0.097*	0.399 (3)
C35'	0.3811 (7)	0.4262 (3)	0.6770 (3)	0.0549 (10)	0.399 (3)
H35D	0.4773	0.4150	0.6807	0.082*	0.399 (3)
H35E	0.3368	0.4239	0.7212	0.082*	0.399 (3)
H35F	0.3779	0.4620	0.6611	0.082*	0.399 (3)

	U11	U22	U33	U12	U13	U23
O1	0.0349 (8)	0.0306 (8)	0.0298 (8)	0.0125 (7)	−0.0038 (7)	−0.0014 (6)
O2	0.0208 (7)	0.0249 (8)	0.0238 (7)	0.0003 (6)	−0.0012 (6)	−0.0050 (6)
C21	0.0191 (10)	0.0226 (11)	0.0238 (10)	−0.0024 (9)	0.0019 (8)	0.0038 (9)
C1	0.0190 (10)	0.0223 (11)	0.0185 (9)	0.0035 (8)	0.0001 (8)	0.0034 (8)
C2	0.0204 (10)	0.0224 (10)	0.0197 (10)	0.0020 (8)	−0.0021 (8)	−0.0008 (8)
C3	0.0206 (10)	0.0265 (12)	0.0284 (11)	−0.0013 (9)	0.0030 (9)	0.0020 (9)
C4	0.0259 (11)	0.0295 (12)	0.0228 (10)	0.0040 (10)	0.0086 (9)	0.0058 (9)
C5	0.0333 (12)	0.0321 (12)	0.0213 (10)	0.0091 (10)	0.0022 (10)	0.0004 (9)
C6	0.0387 (13)	0.0331 (13)	0.0260 (11)	0.0116 (11)	−0.0052 (10)	−0.0085 (10)
C7	0.0274 (11)	0.0322 (13)	0.0368 (12)	0.0021 (10)	−0.0070 (10)	−0.0072 (10)
C8	0.0223 (11)	0.0290 (12)	0.0258 (11)	0.0017 (9)	0.0002 (9)	−0.0009 (9)
C9	0.0218 (10)	0.0225 (11)	0.0201 (10)	0.0040 (8)	−0.0015 (8)	0.0012 (8)
C10	0.0253 (11)	0.0223 (11)	0.0195 (10)	0.0055 (9)	0.0000 (8)	0.0025 (8)
C22	0.0252 (11)	0.0251 (12)	0.0232 (10)	0.0012 (9)	0.0010 (9)	−0.0014 (8)
C23	0.0377 (13)	0.0269 (12)	0.0307 (11)	−0.0019 (10)	0.0000 (10)	−0.0033 (9)
C24	0.0345 (12)	0.0383 (13)	0.0275 (11)	0.0004 (11)	0.0090 (10)	−0.0041 (9)
C25	0.0387 (13)	0.0371 (14)	0.0297 (12)	0.0043 (11)	−0.0083 (10)	−0.0058 (10)
O11	0.0449 (10)	0.0526 (11)	0.0469 (10)	0.0205 (9)	0.0125 (9)	0.0172 (9)
O12	0.0248 (8)	0.0240 (8)	0.0302 (7)	0.0000 (6)	0.0037 (6)	0.0000 (6)
C11	0.0211 (10)	0.0209 (11)	0.0211 (10)	0.0035 (8)	−0.0023 (8)	−0.0003 (8)
C12	0.0194 (10)	0.0217 (11)	0.0260 (11)	0.0037 (8)	0.0002 (9)	0.0017 (8)
C13	0.0256 (11)	0.0216 (11)	0.0319 (11)	−0.0002 (9)	−0.0062 (9)	−0.0026 (9)
C14	0.0311 (12)	0.0272 (12)	0.0227 (10)	0.0051 (10)	−0.0078 (9)	−0.0051 (9)
C15	0.0398 (13)	0.0362 (13)	0.0214 (11)	0.0079 (11)	0.0009 (10)	−0.0022 (10)
C16	0.0327 (12)	0.0445 (14)	0.0282 (12)	0.0059 (11)	0.0101 (10)	0.0055 (10)
C17	0.0314 (12)	0.0330 (13)	0.0388 (13)	−0.0035 (10)	0.0059 (11)	0.0024 (11)
C18	0.0293 (11)	0.0238 (11)	0.0271 (11)	−0.0007 (10)	0.0013 (9)	−0.0010 (9)
C19	0.0227 (10)	0.0218 (11)	0.0201 (10)	0.0044 (9)	−0.0015 (9)	0.0008 (8)
C20	0.0277 (11)	0.0248 (11)	0.0208 (10)	0.0062 (9)	−0.0030 (9)	−0.0001 (9)
C31	0.0285 (12)	0.0292 (12)	0.0298 (11)	−0.0034 (10)	−0.0030 (10)	−0.0011 (10)
C32	0.0392 (13)	0.0397 (14)	0.0377 (12)	−0.0006 (12)	0.0118 (11)	0.0038 (11)
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)
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)

O1—C21	1.197 (2)	C12—C13	1.398 (3)
O2—C21	1.365 (2)	C13—C14	1.360 (3)
O2—C2	1.404 (2)	C13—H13	0.9500
C21—C22	1.513 (3)	C14—C20	1.412 (3)
C1—C2	1.363 (3)	C14—H14	0.9500
C1—C9	1.431 (3)	C15—C16	1.360 (3)
C1—C1i	1.504 (4)	C15—C20	1.412 (3)
C2—C3	1.401 (3)	C15—H15	0.9500
C3—C4	1.358 (3)	C16—C17	1.409 (3)
C3—H3	0.9500	C16—H16	0.9500
C4—C10	1.408 (3)	C17—C18	1.367 (3)
C4—H4	0.9500	C17—H17	0.9500
C5—C6	1.361 (3)	C18—C19	1.411 (3)
C5—C10	1.417 (3)	C18—H18	0.9500
C5—H5	0.9500	C19—C20	1.426 (3)
C6—C7	1.407 (3)	C31—C32	1.505 (3)
C6—H6	0.9500	C32—C33'	1.407 (7)
C7—C8	1.366 (3)	C32—C33	1.441 (5)
C7—H7	0.9500	C32—C34	1.531 (5)
C8—C9	1.417 (3)	C32—C34'	1.549 (7)
C8—H8	0.9500	C32—C35	1.620 (5)
C9—C10	1.419 (3)	C32—C35'	1.644 (6)
C22—C25	1.522 (3)	C33—H33A	0.9800
C22—C24	1.533 (3)	C33—H33B	0.9800
C22—C23	1.535 (3)	C33—H33C	0.9800
C23—H23A	0.9800	C34—H34A	0.9800
C23—H23B	0.9800	C34—H34B	0.9800
C23—H23C	0.9800	C34—H34C	0.9800
C24—H24A	0.9800	C35—H35A	0.9800
C24—H24B	0.9800	C35—H35B	0.9800
C24—H24C	0.9800	C35—H35C	0.9800
C25—H25A	0.9800	C33'—H33D	0.9800
C25—H25B	0.9800	C33'—H33E	0.9800
C25—H25C	0.9800	C33'—H33F	0.9800
O11—C31	1.194 (3)	C34'—H34D	0.9800
O12—C31	1.368 (2)	C34'—H34E	0.9800
O12—C12	1.405 (2)	C34'—H34F	0.9800
C11—C12	1.367 (3)	C35'—H35D	0.9800
C11—C19	1.431 (3)	C35'—H35E	0.9800
C11—C11ii	1.496 (4)	C35'—H35F	0.9800
C21—O2—C2	117.00 (15)	C15—C16—H16	120.0
O1—C21—O2	122.72 (18)	C17—C16—H16	120.0
O1—C21—C22	126.45 (18)	C18—C17—C16	120.6 (2)
O2—C21—C22	110.82 (16)	C18—C17—H17	119.7
C2—C1—C9	118.25 (17)	C16—C17—H17	119.7
C2—C1—C1i	120.46 (17)	C17—C18—C19	120.8 (2)
C9—C1—C1i	121.29 (17)	C17—C18—H18	119.6
C1—C2—C3	123.17 (18)	C19—C18—H18	119.6
C1—C2—O2	117.69 (17)	C18—C19—C20	118.49 (18)
C3—C2—O2	119.05 (17)	C18—C19—C11	122.06 (17)
C4—C3—C2	119.06 (19)	C20—C19—C11	119.42 (18)
C4—C3—H3	120.5	C14—C20—C15	121.75 (18)
C2—C3—H3	120.5	C14—C20—C19	119.18 (18)
C3—C4—C10	120.98 (19)	C15—C20—C19	119.03 (19)
C3—C4—H4	119.5	O11—C31—O12	121.7 (2)
C10—C4—H4	119.5	O11—C31—C32	126.1 (2)
C6—C5—C10	121.0 (2)	O12—C31—C32	112.11 (19)
C6—C5—H5	119.5	C33'—C32—C33	128.1 (4)
C10—C5—H5	119.5	C33'—C32—C31	120.0 (4)
C5—C6—C7	119.94 (19)	C33—C32—C31	111.9 (3)
C5—C6—H6	120.0	C33'—C32—C34	43.1 (5)
C7—C6—H6	120.0	C33—C32—C34	115.2 (4)
C8—C7—C6	120.7 (2)	C31—C32—C34	112.2 (3)
C8—C7—H7	119.7	C33'—C32—C34'	115.4 (6)
C6—C7—H7	119.7	C33—C32—C34'	41.6 (4)
C7—C8—C9	120.79 (19)	C31—C32—C34'	109.4 (3)
C7—C8—H8	119.6	C34—C32—C34'	138.3 (4)
C9—C8—H8	119.6	C33'—C32—C35	61.7 (5)
C8—C9—C10	118.51 (17)	C33—C32—C35	109.5 (4)
C8—C9—C1	122.49 (17)	C31—C32—C35	102.0 (2)
C10—C9—C1	118.97 (17)	C34—C32—C35	104.8 (3)
C4—C10—C5	121.36 (19)	C34'—C32—C35	69.8 (4)
C4—C10—C9	119.55 (17)	C33'—C32—C35'	108.6 (6)
C5—C10—C9	119.05 (19)	C33—C32—C35'	59.0 (4)
C21—C22—C25	109.06 (16)	C31—C32—C35'	100.0 (3)
C21—C22—C24	107.99 (16)	C34—C32—C35'	68.6 (4)
C25—C22—C24	109.79 (16)	C34'—C32—C35'	100.5 (5)
C21—C22—C23	109.30 (16)	C35—C32—C35'	157.8 (3)
C25—C22—C23	110.28 (18)	C32—C33—H33A	109.5
C24—C22—C23	110.37 (18)	C32—C33—H33B	109.5
C22—C23—H23A	109.5	H33A—C33—H33B	109.5
C22—C23—H23B	109.5	C32—C33—H33C	109.5
H23A—C23—H23B	109.5	H33A—C33—H33C	109.5
C22—C23—H23C	109.5	H33B—C33—H33C	109.5
H23A—C23—H23C	109.5	C32—C34—H34A	109.5
H23B—C23—H23C	109.5	C32—C34—H34B	109.5
C22—C24—H24A	109.5	H34A—C34—H34B	109.5
C22—C24—H24B	109.5	C32—C34—H34C	109.5
H24A—C24—H24B	109.5	H34A—C34—H34C	109.5
C22—C24—H24C	109.5	H34B—C34—H34C	109.5
H24A—C24—H24C	109.5	C32—C35—H35A	109.5
H24B—C24—H24C	109.5	C32—C35—H35B	109.5
C22—C25—H25A	109.5	H35A—C35—H35B	109.5
C22—C25—H25B	109.5	C32—C35—H35C	109.5
H25A—C25—H25B	109.5	H35A—C35—H35C	109.5
C22—C25—H25C	109.5	H35B—C35—H35C	109.5
H25A—C25—H25C	109.5	C32—C33'—H33D	109.5
H25B—C25—H25C	109.5	C32—C33'—H33E	109.5
C31—O12—C12	115.44 (15)	H33D—C33'—H33E	109.5
C12—C11—C19	117.72 (17)	C32—C33'—H33F	109.5
C12—C11—C11ii	120.13 (17)	H33D—C33'—H33F	109.5
C19—C11—C11ii	122.14 (17)	H33E—C33'—H33F	109.5
C11—C12—C13	123.51 (19)	C32—C34'—H34D	109.5
C11—C12—O12	118.07 (17)	C32—C34'—H34E	109.5
C13—C12—O12	118.40 (18)	H34D—C34'—H34E	109.5
C14—C13—C12	119.23 (19)	C32—C34'—H34F	109.5
C14—C13—H13	120.4	H34D—C34'—H34F	109.5
C12—C13—H13	120.4	H34E—C34'—H34F	109.5
C13—C14—C20	120.87 (18)	C32—C35'—H35D	109.5
C13—C14—H14	119.6	C32—C35'—H35E	109.5
C20—C14—H14	119.6	H35D—C35'—H35E	109.5
C16—C15—C20	121.1 (2)	C32—C35'—H35F	109.5
C16—C15—H15	119.5	H35D—C35'—H35F	109.5
C20—C15—H15	119.5	H35E—C35'—H35F	109.5
C15—C16—C17	120.0 (2)