Preference for the Diels-Alder addition of dienes syn to the O atom in cross-conjugated spiro­cyclic cyclo­hexadienones

In the Diels-Alder reaction, the preferred addition of dienes syn to the O atom in cross-conjugated cyclo­hexadienones containing an oxa-­spiro ring system is observed. The two structures reported here, namely rel-(1R,4aR,9S,9aS,10R)-4a,9,9a,10-tetra­hydro-9,10-di­phenyl­spiro­[9,10-epoxy­anthra­cene-1(4H),2'-oxiran]-4-one, C₂₇H₂₀O₃, and rel-(1R,4aS,9R,9aS,10S)-4a,9,9a,10-tetra­hydro-9,10-di­phenyl­spiro­[9,10-epoxy­anthracene-1(4H),2'-oxetane]-4-one, C₂₈H₂₂O₃, are the minor and sole products, respectively, of the reactions of di­phenyl­isobenzo­furan with two slightly different cyclo­hexadienones. These structures differ in the size of the oxa-­spiro ring, by one C atom, and in the relative configuration at the spiro­cyclic ring C atom, leading to some minor conformational differences between the two compounds.

S1. Comment

Cross-conjugated cyclohexadienones carrying an oxaspiro ring, as in (I), hold interest as Diels–Alder dienophiles in that control of π-facial diastereoselectivity by the heteroatom is operative (Wipf & Kim, 1994; Tran-Hu—Dâu et al., 2001; Silvero et al., 1998; Takagi et al., 2003; Paquette et al., 2003). Irrespective of the size of the spiro ring and the resultant changes in basicity at the O center and overall steric contributions, diene approach from the direction syn to the O atom is heavily preferred (Ohkata et al., 2004). Diphenylisobenzofuran, (II) (Newman, 1961), one of the notably reactive dienes, is used in the present study because this compound often leads to crystalline products. We compare here the structural features of (III), the minor Diels–Alder adduct from the reaction of diphenylisobenzofuran with (I) (n=1), with those of (IV), the sole [4 + 2] product formed upon reaction of diphenylisobenzofuran with (I) (n = 2).

The size of the oxaspiro ring and the relative configuration of the spirocyclic atom C10 are the main features that differentiate these two structures. For both structures, the six-membered ring containing the spiro C atom (C9–C14) is in a boat conformation. In (III), atoms C10 and C13 lie 0.112 (1) and 0.236 (1) Å, respectively, from the least-squares plane defined by atoms C9, C11, C12 and C14. In (IV), atoms C10 and C13 lie 0.382 (1) and 0.284 (1) Å, respectively, from the analogous plane. The two boat conformations are bent in opposite directions, as seen in Figs. 1 and 2.

Another conformational difference between the two structures is seen in the orientation of the phenyl rings. This can be described by the dihedral angle between a phenyl ring and the plane defined by atoms C1, O1 and C8. In (III), the dihedral angle between the C22–C27 phenyl ring and the C1/O1/C8 plane is 84.0 (1)°. The analogous angle in (IV) is 83.9 (1)°, where the phenyl ring consists of atoms C21–C26. Note that both phenyl rings are located on the same end of the molecule as the spiro ring. For the other two phenyl rings, the dihedral angles are significantly different; in (III), this dihedral angle is 44.5 (1)°, while for (IV) it is 11.9 (1)°.

The oxetane ring in (IV) can be compared with the structure of oxetane (C₃H₆O), which was determined at two temperatures, viz. 90 and 140 K (Luger & Buschmann, 1984). Oxetane was found to have several interesting features, including ring puckering, as described by the dihedral angle between the C/O/C and C/C/C planes, of 10.7 (1)° at 90 K and 8.7 (2)° at 140 K, long C—O bond lengths of 1.460 (1) Å at 90 K and 1.443 (2) Å at 140 K, and an acute C—C—C angle of 84.79 (9)° at 90 K and 85.0 (1)° at 140 K. These same features are observed in (IV), with a ring-puckering angle of 5.8 (1)°, long O3—C27 O3—C10 bond lengths of 1.4514 (17) and 1.4656 (15) Å, and an acute C27—C28—C10 angle of 85.8 (1)°. There is only one other structure in the Cambridge Structural Database (Allen, 2002, Version 5.25 of November 2003) that contains an analogous spiro oxetane ring, where the spiro C atom is located adjacent to the O atom, namely 6,8,9-tris(ethyleneoxy)-2,4,10- trioxatricyclo(3.3.1.1)decane (Paquette et al., 2001). This compound contains three spiro oxetane rings and exhibits the above-mentioned features of (IV) and oxetane.

S2. Experimental

To a solution (1.0 M) of (I) in benzene was added one equivalent of diphenylisobenzofuran, (II). The reaction mixture was shielded from laboratory light and heated at the reflux temperature. When the reaction was complete (8.5 h for n=1 and 6 h for n=2), the volatile constituents were removed under reduced pressure, and the residue was purified by column chromatography on silica gel. The reaction with n=1 resulted in the isolation of two adducts in a 78:22 ratio, with (III) as the minor component. When the co-reactant was (I) with n=2, compound (IV) was formed exclusively. Compounds (III) and (IV) were crystallized by dissolving each in a minimal amount of ethyl acetate, and then adding hexane until the solution turned slightly cloudy. The melting points of (III) and (IV) are 406–408 K and 411–413 K, respectively.

S3. Refinement

The H atoms for both structures were placed at calculated positions and treated using using a riding model, with U_iso(H) values of 1.2U_eq(C). The C—H distances ranged from 0.95 to 1.00 Å, depending on the type of C atom. PLATON (Spek, 2003) was used to calculated some geometric parameters.

Computing details

For both compounds, data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: reference?.

Figures

	Fig. 1. The structure of (III), drawn with 50% probability displacement ellipsoids.
	Fig. 2. The structure of (IV), drawn with 50% probability displacement ellipsoids.

(III) rel-(1R,4aR,9S,9aS,10R)-4a,9,9a,10-tetrahydro-9,10-diphenylspiro[9,10- epoxyanthracene-1(4H),2'-oxiran]-4–one

Crystal data

C27H20O3	F(000) = 824
Mr = 392.43	Dx = 1.337 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 4662 reflections
a = 10.322 (1) Å	θ = 2.0–27.5°
b = 14.239 (1) Å	µ = 0.09 mm^−1
c = 14.138 (1) Å	T = 200 K
β = 110.254 (4)°	Chunk, pale yellow
V = 1949.3 (3) Å^3	0.35 × 0.31 × 0.19 mm
Z = 4

Data collection

Nonius KappaCCD diffractometer	3424 reflections with I > 2σ(I)
Radiation source: fine–focus sealed tube	Rint = 0.036
Graphite monochromator	θmax = 27.5°, θmin = 2.5°
ϕ and ω scans	h = −13→13
41110 measured reflections	k = −18→18
4474 independent reflections	l = −18→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.118	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0599P)^2 + 0.4364P] where P = (Fo^2 + 2Fc^2)/3
4474 reflections	(Δ/σ)max = 0.001
271 parameters	Δρmax = 0.34 e Å^−3
0 restraints	Δρmin = −0.23 e Å^−3

Special details

Experimental. All work was done at 200 K using an Oxford Cryosystems Cryostream Cooler. A quadrant of reciprocal space was measured with a redundancy factor of 4.2, which means that 90% of the data was measured at least 4.2 times. A combination of phi and omega scans with a frame width of 1.0° was used for data collection. Data integration was done with DENZO (Otwinowski & Minor, 1997). Scaling and merging of the data was done with SCALEPACK (Otwinowski & Minor, 1997).

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.78521 (9)	0.91350 (6)	0.79337 (6)	0.0249 (2)
O2	0.92312 (12)	0.92687 (9)	0.53963 (9)	0.0499 (3)
O3	0.38837 (11)	0.86833 (8)	0.51460 (9)	0.0464 (3)
C1	0.87191 (13)	0.91525 (9)	0.73112 (9)	0.0245 (3)
C2	0.88851 (13)	0.81059 (9)	0.71718 (9)	0.0244 (3)
C3	0.99011 (14)	0.75818 (10)	0.69891 (10)	0.0293 (3)
H3	1.0731	0.7865	0.6983	0.035*
C4	0.96651 (15)	0.66200 (10)	0.68136 (10)	0.0328 (3)
H4	1.0353	0.6240	0.6698	0.039*
C5	0.84444 (15)	0.62133 (10)	0.68061 (10)	0.0328 (3)
H5	0.8310	0.5558	0.6690	0.039*
C6	0.74068 (14)	0.67491 (10)	0.69667 (10)	0.0292 (3)
H6	0.6561	0.6470	0.6945	0.035*
C7	0.76466 (13)	0.76999 (9)	0.71587 (9)	0.0251 (3)
C8	0.67729 (13)	0.85079 (9)	0.73182 (9)	0.0254 (3)
C9	0.62651 (14)	0.90870 (9)	0.63186 (10)	0.0285 (3)
H9	0.5710	0.9626	0.6426	0.034*
C10	0.53647 (14)	0.85611 (10)	0.53852 (11)	0.0346 (3)
C11	0.57426 (18)	0.85937 (12)	0.44781 (12)	0.0457 (4)
H11	0.5085	0.8379	0.3863	0.055*
C12	0.69449 (18)	0.89046 (12)	0.44641 (12)	0.0459 (4)
H12	0.7102	0.8917	0.3841	0.055*
C13	0.80386 (16)	0.92290 (10)	0.53727 (11)	0.0349 (3)
C14	0.76543 (14)	0.94965 (10)	0.62811 (10)	0.0283 (3)
H14	0.7602	1.0197	0.6304	0.034*
C15	0.44699 (16)	0.77763 (12)	0.54481 (13)	0.0456 (4)
H15A	0.4275	0.7281	0.4926	0.055*
H15B	0.4543	0.7551	0.6127	0.055*
C16	0.99695 (13)	0.97469 (9)	0.78415 (10)	0.0258 (3)
C17	1.06064 (15)	0.96424 (11)	0.88772 (11)	0.0363 (3)
H17	1.0288	0.9173	0.9222	0.044*
C18	1.16971 (16)	1.02129 (12)	0.94119 (11)	0.0432 (4)
H18	1.2114	1.0140	1.0121	0.052*
C19	1.21823 (15)	1.08892 (11)	0.89182 (12)	0.0399 (4)
H19	1.2936	1.1279	0.9285	0.048*
C20	1.15666 (15)	1.09941 (11)	0.78916 (12)	0.0381 (4)
H20	1.1898	1.1458	0.7550	0.046*
C21	1.04651 (14)	1.04270 (10)	0.73515 (11)	0.0332 (3)
H21	1.0049	1.0505	0.6643	0.040*
C22	0.57793 (13)	0.83223 (10)	0.78705 (10)	0.0290 (3)
C23	0.61108 (15)	0.76515 (11)	0.86332 (10)	0.0339 (3)
H23	0.6920	0.7282	0.8762	0.041*
C24	0.52772 (17)	0.75131 (13)	0.92095 (11)	0.0435 (4)
H24	0.5519	0.7054	0.9729	0.052*
C25	0.40968 (18)	0.80445 (13)	0.90257 (13)	0.0493 (4)
H25	0.3531	0.7957	0.9424	0.059*
C26	0.37405 (18)	0.87026 (13)	0.82627 (15)	0.0510 (5)
H26	0.2922	0.9062	0.8132	0.061*
C27	0.45736 (16)	0.88431 (11)	0.76832 (13)	0.0418 (4)
H27	0.4319	0.9296	0.7158	0.050*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0243 (4)	0.0265 (5)	0.0248 (5)	−0.0026 (4)	0.0095 (4)	−0.0024 (4)
O2	0.0553 (7)	0.0586 (8)	0.0441 (7)	−0.0114 (6)	0.0276 (6)	−0.0065 (6)
O3	0.0313 (5)	0.0467 (7)	0.0494 (7)	0.0033 (5)	−0.0009 (5)	−0.0034 (5)
C1	0.0262 (6)	0.0251 (7)	0.0233 (6)	−0.0005 (5)	0.0102 (5)	0.0009 (5)
C2	0.0276 (6)	0.0238 (7)	0.0208 (6)	0.0000 (5)	0.0072 (5)	0.0011 (5)
C3	0.0289 (7)	0.0316 (7)	0.0287 (7)	0.0011 (6)	0.0117 (6)	0.0014 (6)
C4	0.0369 (8)	0.0309 (8)	0.0319 (7)	0.0071 (6)	0.0136 (6)	−0.0008 (6)
C5	0.0431 (8)	0.0235 (7)	0.0297 (7)	0.0012 (6)	0.0100 (6)	−0.0017 (6)
C6	0.0308 (7)	0.0275 (7)	0.0278 (7)	−0.0038 (6)	0.0082 (6)	0.0003 (5)
C7	0.0270 (6)	0.0258 (7)	0.0218 (6)	0.0008 (5)	0.0074 (5)	0.0018 (5)
C8	0.0233 (6)	0.0257 (7)	0.0251 (6)	−0.0009 (5)	0.0057 (5)	−0.0023 (5)
C9	0.0281 (7)	0.0274 (7)	0.0273 (7)	0.0026 (5)	0.0062 (5)	−0.0008 (5)
C10	0.0306 (7)	0.0347 (8)	0.0307 (7)	0.0041 (6)	0.0006 (6)	−0.0008 (6)
C11	0.0502 (10)	0.0496 (10)	0.0283 (8)	0.0003 (8)	0.0020 (7)	−0.0069 (7)
C12	0.0580 (10)	0.0519 (10)	0.0266 (8)	0.0001 (8)	0.0132 (7)	−0.0030 (7)
C13	0.0435 (8)	0.0335 (8)	0.0291 (7)	−0.0015 (6)	0.0143 (6)	0.0039 (6)
C14	0.0330 (7)	0.0244 (7)	0.0256 (6)	0.0011 (5)	0.0076 (5)	0.0013 (5)
C15	0.0411 (9)	0.0411 (9)	0.0425 (9)	−0.0051 (7)	−0.0008 (7)	−0.0014 (7)
C16	0.0262 (6)	0.0243 (7)	0.0281 (7)	0.0008 (5)	0.0110 (5)	−0.0017 (5)
C17	0.0360 (8)	0.0417 (9)	0.0300 (7)	−0.0073 (7)	0.0099 (6)	0.0033 (6)
C18	0.0395 (8)	0.0567 (10)	0.0294 (8)	−0.0092 (7)	0.0068 (6)	−0.0041 (7)
C19	0.0330 (8)	0.0415 (9)	0.0453 (9)	−0.0097 (7)	0.0135 (7)	−0.0118 (7)
C20	0.0362 (8)	0.0350 (8)	0.0446 (9)	−0.0091 (6)	0.0159 (7)	0.0001 (7)
C21	0.0340 (7)	0.0332 (8)	0.0318 (7)	−0.0042 (6)	0.0107 (6)	0.0022 (6)
C22	0.0247 (6)	0.0309 (7)	0.0314 (7)	−0.0045 (6)	0.0097 (5)	−0.0074 (6)
C23	0.0299 (7)	0.0435 (9)	0.0279 (7)	−0.0048 (6)	0.0095 (6)	−0.0034 (6)
C24	0.0466 (9)	0.0551 (10)	0.0315 (8)	−0.0152 (8)	0.0169 (7)	−0.0059 (7)
C25	0.0475 (10)	0.0606 (11)	0.0515 (10)	−0.0181 (8)	0.0322 (8)	−0.0192 (9)
C26	0.0381 (9)	0.0518 (11)	0.0732 (12)	−0.0016 (8)	0.0322 (9)	−0.0139 (9)
C27	0.0356 (8)	0.0381 (9)	0.0560 (10)	0.0013 (7)	0.0215 (7)	−0.0018 (7)

Geometric parameters (Å, º)

O1—C1	1.4565 (15)	C12—C13	1.461 (2)
O1—C8	1.4575 (15)	C12—H12	0.9500
O2—C13	1.2211 (18)	C13—C14	1.5180 (19)
O3—C15	1.427 (2)	C14—H14	1.0000
O3—C10	1.4572 (17)	C15—H15A	0.9900
C1—C16	1.5080 (18)	C15—H15B	0.9900
C1—C2	1.5206 (18)	C16—C21	1.3874 (19)
C1—C14	1.5686 (18)	C16—C17	1.3899 (19)
C2—C3	1.3824 (19)	C17—C18	1.382 (2)
C2—C7	1.3972 (18)	C17—H17	0.9500
C3—C4	1.398 (2)	C18—C19	1.381 (2)
C3—H3	0.9500	C18—H18	0.9500
C4—C5	1.383 (2)	C19—C20	1.376 (2)
C4—H4	0.9500	C19—H19	0.9500
C5—C6	1.396 (2)	C20—C21	1.388 (2)
C5—H5	0.9500	C20—H20	0.9500
C6—C7	1.3860 (19)	C21—H21	0.9500
C6—H6	0.9500	C22—C23	1.392 (2)
C7—C8	1.5260 (18)	C22—C27	1.393 (2)
C8—C22	1.5118 (18)	C23—C24	1.389 (2)
C8—C9	1.5617 (18)	C23—H23	0.9500
C9—C10	1.5221 (19)	C24—C25	1.380 (3)
C9—C14	1.5657 (19)	C24—H24	0.9500
C9—H9	1.0000	C25—C26	1.379 (3)
C10—C11	1.465 (2)	C25—H25	0.9500
C10—C15	1.472 (2)	C26—C27	1.392 (2)
C11—C12	1.324 (2)	C26—H26	0.9500
C11—H11	0.9500	C27—H27	0.9500
C1—O1—C8	98.75 (9)	O2—C13—C14	121.43 (13)
C15—O3—C10	61.35 (10)	C12—C13—C14	118.33 (13)
O1—C1—C16	107.95 (10)	C13—C14—C9	116.47 (12)
O1—C1—C2	100.48 (9)	C13—C14—C1	113.76 (11)
C16—C1—C2	119.93 (11)	C9—C14—C1	101.99 (10)
O1—C1—C14	100.76 (10)	C13—C14—H14	108.1
C16—C1—C14	119.36 (11)	C9—C14—H14	108.1
C2—C1—C14	105.06 (10)	C1—C14—H14	108.1
C3—C2—C7	121.59 (12)	O3—C15—C10	60.32 (10)
C3—C2—C1	132.85 (12)	O3—C15—H15A	117.7
C7—C2—C1	105.29 (11)	C10—C15—H15A	117.7
C2—C3—C4	117.72 (13)	O3—C15—H15B	117.7
C2—C3—H3	121.1	C10—C15—H15B	117.7
C4—C3—H3	121.1	H15A—C15—H15B	114.9
C5—C4—C3	120.91 (13)	C21—C16—C17	118.63 (13)
C5—C4—H4	119.5	C21—C16—C1	122.92 (12)
C3—C4—H4	119.5	C17—C16—C1	118.36 (12)
C4—C5—C6	121.19 (13)	C18—C17—C16	120.80 (14)
C4—C5—H5	119.4	C18—C17—H17	119.6
C6—C5—H5	119.4	C16—C17—H17	119.6
C7—C6—C5	118.08 (13)	C19—C18—C17	120.18 (14)
C7—C6—H6	121.0	C19—C18—H18	119.9
C5—C6—H6	121.0	C17—C18—H18	119.9
C6—C7—C2	120.48 (12)	C20—C19—C18	119.53 (14)
C6—C7—C8	133.69 (12)	C20—C19—H19	120.2
C2—C7—C8	105.71 (11)	C18—C19—H19	120.2
O1—C8—C22	108.28 (10)	C19—C20—C21	120.55 (14)
O1—C8—C7	100.46 (9)	C19—C20—H20	119.7
C22—C8—C7	119.06 (11)	C21—C20—H20	119.7
O1—C8—C9	99.47 (10)	C16—C21—C20	120.31 (13)
C22—C8—C9	118.98 (11)	C16—C21—H21	119.8
C7—C8—C9	107.14 (10)	C20—C21—H21	119.8
C10—C9—C8	115.96 (11)	C23—C22—C27	118.45 (13)
C10—C9—C14	116.44 (12)	C23—C22—C8	119.43 (12)
C8—C9—C14	101.71 (10)	C27—C22—C8	122.00 (13)
C10—C9—H9	107.4	C24—C23—C22	121.06 (15)
C8—C9—H9	107.4	C24—C23—H23	119.5
C14—C9—H9	107.4	C22—C23—H23	119.5
O3—C10—C11	111.66 (12)	C25—C24—C23	119.84 (16)
O3—C10—C15	58.33 (9)	C25—C24—H24	120.1
C11—C10—C15	116.09 (14)	C23—C24—H24	120.1
O3—C10—C9	114.77 (12)	C26—C25—C24	119.92 (15)
C11—C10—C9	118.41 (13)	C26—C25—H25	120.0
C15—C10—C9	121.91 (13)	C24—C25—H25	120.0
C12—C11—C10	123.96 (14)	C25—C26—C27	120.40 (16)
C12—C11—H11	118.0	C25—C26—H26	119.8
C10—C11—H11	118.0	C27—C26—H26	119.8
C11—C12—C13	122.39 (15)	C26—C27—C22	120.32 (16)
C11—C12—H12	118.8	C26—C27—H27	119.8
C13—C12—H12	118.8	C22—C27—H27	119.8
O2—C13—C12	120.23 (14)
C8—O1—C1—C16	−177.64 (10)	C11—C12—C13—O2	160.20 (17)
C8—O1—C1—C2	−51.25 (11)	C11—C12—C13—C14	−18.8 (2)
C8—O1—C1—C14	56.46 (11)	O2—C13—C14—C9	−158.41 (14)
O1—C1—C2—C3	−153.39 (14)	C12—C13—C14—C9	20.60 (19)
C16—C1—C2—C3	−35.5 (2)	O2—C13—C14—C1	−40.20 (19)
C14—C1—C2—C3	102.34 (16)	C12—C13—C14—C1	138.81 (14)
O1—C1—C2—C7	32.76 (12)	C10—C9—C14—C13	−7.02 (17)
C16—C1—C2—C7	150.68 (11)	C8—C9—C14—C13	120.02 (12)
C14—C1—C2—C7	−71.51 (12)	C10—C9—C14—C1	−131.48 (12)
C7—C2—C3—C4	−1.56 (19)	C8—C9—C14—C1	−4.44 (12)
C1—C2—C3—C4	−174.59 (13)	O1—C1—C14—C13	−156.86 (11)
C2—C3—C4—C5	1.1 (2)	C16—C1—C14—C13	85.30 (15)
C3—C4—C5—C6	0.4 (2)	C2—C1—C14—C13	−52.80 (14)
C4—C5—C6—C7	−1.5 (2)	O1—C1—C14—C9	−30.60 (12)
C5—C6—C7—C2	1.10 (19)	C16—C1—C14—C9	−148.44 (11)
C5—C6—C7—C8	176.58 (13)	C2—C1—C14—C9	73.45 (12)
C3—C2—C7—C6	0.45 (19)	C11—C10—C15—O3	−100.41 (14)
C1—C2—C7—C6	175.16 (12)	C9—C10—C15—O3	101.29 (14)
C3—C2—C7—C8	−176.15 (12)	O1—C1—C16—C21	−134.13 (13)
C1—C2—C7—C8	−1.44 (13)	C2—C1—C16—C21	111.84 (15)
C1—O1—C8—C22	175.73 (10)	C14—C1—C16—C21	−20.08 (19)
C1—O1—C8—C7	50.19 (10)	O1—C1—C16—C17	42.28 (16)
C1—O1—C8—C9	−59.35 (10)	C2—C1—C16—C17	−71.75 (16)
C6—C7—C8—O1	153.74 (14)	C14—C1—C16—C17	156.33 (12)
C2—C7—C8—O1	−30.31 (12)	C21—C16—C17—C18	1.0 (2)
C6—C7—C8—C22	35.9 (2)	C1—C16—C17—C18	−175.58 (14)
C2—C7—C8—C22	−148.18 (11)	C16—C17—C18—C19	−0.9 (2)
C6—C7—C8—C9	−102.85 (16)	C17—C18—C19—C20	0.4 (2)
C2—C7—C8—C9	73.10 (12)	C18—C19—C20—C21	0.0 (2)
O1—C8—C9—C10	165.37 (11)	C17—C16—C21—C20	−0.6 (2)
C22—C8—C9—C10	−77.51 (15)	C1—C16—C21—C20	175.82 (13)
C7—C8—C9—C10	61.24 (14)	C19—C20—C21—C16	0.1 (2)
O1—C8—C9—C14	38.02 (11)	O1—C8—C22—C23	−81.07 (15)
C22—C8—C9—C14	155.14 (11)	C7—C8—C22—C23	32.65 (18)
C7—C8—C9—C14	−66.10 (12)	C9—C8—C22—C23	166.53 (12)
C15—O3—C10—C11	108.12 (15)	O1—C8—C22—C27	94.92 (15)
C15—O3—C10—C9	−113.54 (15)	C7—C8—C22—C27	−151.36 (13)
C8—C9—C10—O3	96.05 (14)	C9—C8—C22—C27	−17.48 (19)
C14—C9—C10—O3	−144.34 (12)	C27—C22—C23—C24	−1.2 (2)
C8—C9—C10—C11	−128.57 (14)	C8—C22—C23—C24	174.95 (13)
C14—C9—C10—C11	−8.96 (18)	C22—C23—C24—C25	0.2 (2)
C8—C9—C10—C15	29.24 (18)	C23—C24—C25—C26	0.8 (2)
C14—C9—C10—C15	148.86 (13)	C24—C25—C26—C27	−0.8 (3)
O3—C10—C11—C12	149.43 (17)	C25—C26—C27—C22	−0.2 (3)
C15—C10—C11—C12	−146.33 (17)	C23—C22—C27—C26	1.2 (2)
C9—C10—C11—C12	12.8 (2)	C8—C22—C27—C26	−174.83 (14)
C10—C11—C12—C13	1.5 (3)

(IV) rel-(1R,4aS,9R,9aS,10S)-4a,9,9a,10-tetrahydro-9,10-diphenyl- spiro[9,10-epoxyanthracene-1(4H),2'-oxetane]-4-one

Crystal data

C28H22O3	F(000) = 856
Mr = 406.46	Dx = 1.339 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4806 reflections
a = 8.434 (1) Å	θ = 2.0–27.5°
b = 13.586 (1) Å	µ = 0.09 mm^−1
c = 17.597 (2) Å	T = 200 K
β = 90.646 (4)°	Rectangular chunk, pale yellow
V = 2016.3 (4) Å^3	0.35 × 0.27 × 0.23 mm
Z = 4

Data collection

Nonius KappaCCD diffractometer	3513 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.035
Graphite monochromator	θmax = 27.5°, θmin = 2.3°
ϕ and ω scans	h = −10→10
38808 measured reflections	k = −17→17
4609 independent reflections	l = −22→22

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.112	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0627P)^2 + 0.2487P] where P = (Fo^2 + 2Fc^2)/3
4609 reflections	(Δ/σ)max < 0.001
280 parameters	Δρmax = 0.19 e Å^−3
0 restraints	Δρmin = −0.24 e Å^−3

Special details

Experimental. All work was done at 200 K using an Oxford Cryosystems Cryostream Cooler. A quadrant of reciprocal space was measured with a redundancy factor of 4.1, which means that 90% of the data was measured at least 4.1 times. A combination of phi and omega scans with a frame width of 1.0° was used for data collection. Data integration was done with DENZO (Otwinowski & Minor, 1997). Scaling and merging of the data was done with SCALEPACK (Otwinowski & Minor, 1997).

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.17223 (9)	0.11593 (6)	0.37571 (5)	0.0274 (2)
O2	0.55310 (11)	−0.11098 (7)	0.39718 (5)	0.0379 (2)
O3	0.59848 (11)	0.28872 (6)	0.36886 (5)	0.0392 (2)
C1	0.25689 (14)	0.02912 (8)	0.35240 (7)	0.0258 (3)
C2	0.31367 (14)	0.05935 (9)	0.27394 (7)	0.0266 (3)
C3	0.35910 (15)	0.00763 (10)	0.20995 (7)	0.0323 (3)
H3	0.3456	−0.0617	0.2067	0.039*
C4	0.42534 (17)	0.06086 (10)	0.15041 (7)	0.0389 (3)
H4	0.4566	0.0272	0.1057	0.047*
C5	0.44655 (17)	0.16172 (10)	0.15505 (7)	0.0372 (3)
H5	0.4908	0.1962	0.1134	0.045*
C6	0.40365 (15)	0.21327 (9)	0.22019 (7)	0.0308 (3)
H6	0.4197	0.2823	0.2240	0.037*
C7	0.33717 (14)	0.16081 (9)	0.27897 (6)	0.0266 (3)
C8	0.29413 (14)	0.18929 (9)	0.35950 (7)	0.0265 (3)
C9	0.43228 (14)	0.15023 (9)	0.41230 (6)	0.0267 (3)
H9	0.4103	0.1719	0.4654	0.032*
C10	0.59935 (15)	0.18506 (9)	0.39192 (7)	0.0309 (3)
C11	0.68060 (15)	0.12162 (10)	0.33536 (8)	0.0366 (3)
H11	0.7503	0.1517	0.3002	0.044*
C12	0.65986 (15)	0.02474 (10)	0.33186 (7)	0.0361 (3)
H12	0.7207	−0.0134	0.2975	0.043*
C13	0.54382 (14)	−0.02355 (9)	0.38060 (7)	0.0294 (3)
C14	0.40708 (14)	0.03738 (9)	0.40820 (6)	0.0259 (3)
H14	0.3762	0.0132	0.4596	0.031*
C15	0.16015 (14)	−0.06286 (9)	0.36315 (7)	0.0274 (3)
C16	0.02298 (15)	−0.05935 (10)	0.40624 (8)	0.0341 (3)
H16	−0.0122	0.0017	0.4263	0.041*
C17	−0.06263 (16)	−0.14436 (11)	0.42007 (9)	0.0427 (4)
H17	−0.1558	−0.1412	0.4498	0.051*
C18	−0.01417 (16)	−0.23345 (10)	0.39119 (8)	0.0404 (3)
H18	−0.0742	−0.2913	0.4004	0.049*
C19	0.12263 (17)	−0.23803 (10)	0.34863 (8)	0.0381 (3)
H19	0.1573	−0.2994	0.3290	0.046*
C20	0.20920 (16)	−0.15349 (9)	0.33446 (7)	0.0330 (3)
H20	0.3027	−0.1573	0.3050	0.040*
C21	0.22890 (14)	0.29088 (9)	0.37393 (7)	0.0290 (3)
C22	0.13493 (17)	0.33565 (11)	0.31866 (8)	0.0409 (3)
H22	0.1146	0.3024	0.2721	0.049*
C23	0.07030 (19)	0.42824 (12)	0.33038 (9)	0.0504 (4)
H23	0.0068	0.4581	0.2919	0.060*
C24	0.09832 (18)	0.47701 (11)	0.39802 (9)	0.0487 (4)
H24	0.0553	0.5407	0.4060	0.058*
C25	0.18906 (19)	0.43274 (11)	0.45392 (9)	0.0482 (4)
H25	0.2071	0.4657	0.5009	0.058*
C26	0.25408 (17)	0.34055 (10)	0.44207 (8)	0.0388 (3)
H26	0.3167	0.3109	0.4810	0.047*
C27	0.6901 (2)	0.31675 (12)	0.43573 (9)	0.0510 (4)
H27A	0.6295	0.3573	0.4720	0.061*
H27B	0.7921	0.3488	0.4235	0.061*
C28	0.70866 (17)	0.21050 (10)	0.46077 (8)	0.0413 (3)
H28A	0.6622	0.1956	0.5109	0.050*
H28B	0.8179	0.1845	0.4569	0.050*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0286 (4)	0.0241 (4)	0.0294 (4)	0.0007 (3)	0.0030 (3)	−0.0005 (3)
O2	0.0408 (5)	0.0288 (5)	0.0441 (5)	0.0043 (4)	−0.0041 (4)	−0.0011 (4)
O3	0.0438 (5)	0.0300 (5)	0.0438 (5)	−0.0067 (4)	−0.0058 (4)	0.0094 (4)
C1	0.0271 (6)	0.0244 (6)	0.0258 (6)	0.0016 (5)	0.0008 (5)	−0.0002 (5)
C2	0.0264 (6)	0.0280 (6)	0.0252 (6)	−0.0008 (5)	−0.0024 (5)	0.0012 (5)
C3	0.0377 (7)	0.0299 (7)	0.0293 (6)	−0.0019 (5)	0.0009 (5)	−0.0041 (5)
C4	0.0492 (8)	0.0412 (8)	0.0265 (6)	−0.0029 (6)	0.0057 (6)	−0.0055 (6)
C5	0.0464 (8)	0.0388 (8)	0.0265 (6)	−0.0051 (6)	0.0049 (6)	0.0042 (6)
C6	0.0357 (7)	0.0292 (7)	0.0275 (6)	−0.0011 (5)	−0.0014 (5)	0.0023 (5)
C7	0.0275 (6)	0.0280 (6)	0.0242 (6)	0.0020 (5)	−0.0031 (5)	0.0001 (5)
C8	0.0297 (6)	0.0256 (6)	0.0243 (6)	−0.0015 (5)	0.0004 (5)	0.0016 (5)
C9	0.0320 (6)	0.0261 (6)	0.0219 (6)	0.0002 (5)	−0.0010 (5)	0.0000 (5)
C10	0.0339 (7)	0.0283 (7)	0.0304 (6)	−0.0036 (5)	−0.0044 (5)	0.0053 (5)
C11	0.0299 (7)	0.0439 (8)	0.0360 (7)	−0.0014 (6)	0.0035 (5)	0.0066 (6)
C12	0.0316 (7)	0.0411 (8)	0.0355 (7)	0.0043 (6)	0.0034 (5)	−0.0025 (6)
C13	0.0316 (6)	0.0301 (7)	0.0264 (6)	0.0016 (5)	−0.0064 (5)	−0.0028 (5)
C14	0.0300 (6)	0.0258 (6)	0.0220 (6)	−0.0007 (5)	0.0005 (5)	0.0016 (5)
C15	0.0271 (6)	0.0281 (6)	0.0270 (6)	−0.0005 (5)	−0.0023 (5)	0.0030 (5)
C16	0.0277 (6)	0.0321 (7)	0.0427 (7)	0.0036 (5)	0.0018 (5)	0.0042 (6)
C17	0.0274 (7)	0.0433 (9)	0.0575 (9)	0.0007 (6)	0.0058 (6)	0.0135 (7)
C18	0.0355 (7)	0.0347 (8)	0.0510 (8)	−0.0098 (6)	−0.0034 (6)	0.0088 (6)
C19	0.0468 (8)	0.0290 (7)	0.0385 (7)	−0.0050 (6)	−0.0013 (6)	−0.0006 (6)
C20	0.0365 (7)	0.0297 (7)	0.0330 (7)	−0.0025 (5)	0.0040 (5)	−0.0009 (5)
C21	0.0313 (6)	0.0259 (6)	0.0299 (6)	0.0008 (5)	0.0045 (5)	0.0008 (5)
C22	0.0455 (8)	0.0412 (8)	0.0361 (7)	0.0119 (6)	0.0001 (6)	−0.0006 (6)
C23	0.0514 (9)	0.0491 (9)	0.0509 (9)	0.0213 (7)	0.0080 (7)	0.0122 (7)
C24	0.0530 (9)	0.0284 (8)	0.0650 (10)	0.0102 (7)	0.0207 (8)	0.0033 (7)
C25	0.0579 (10)	0.0351 (8)	0.0516 (9)	0.0017 (7)	0.0057 (7)	−0.0130 (7)
C26	0.0471 (8)	0.0326 (7)	0.0368 (7)	0.0047 (6)	−0.0005 (6)	−0.0038 (6)
C27	0.0604 (10)	0.0428 (9)	0.0498 (9)	−0.0202 (7)	−0.0077 (8)	0.0010 (7)
C28	0.0406 (8)	0.0418 (8)	0.0413 (8)	−0.0091 (6)	−0.0115 (6)	0.0045 (6)

Geometric parameters (Å, º)

O1—C1	1.4408 (14)	C13—C14	1.5046 (17)
O1—C8	1.4623 (14)	C14—H14	1.0000
O2—C13	1.2255 (15)	C15—C16	1.3913 (18)
O3—C27	1.4514 (17)	C15—C20	1.3954 (18)
O3—C10	1.4656 (15)	C16—C17	1.3852 (19)
C1—C15	1.5054 (16)	C16—H16	0.9500
C1—C2	1.5228 (16)	C17—C18	1.376 (2)
C1—C14	1.5979 (16)	C17—H17	0.9500
C2—C3	1.3851 (17)	C18—C19	1.384 (2)
C2—C7	1.3953 (17)	C18—H18	0.9500
C3—C4	1.3950 (18)	C19—C20	1.3851 (18)
C3—H3	0.9500	C19—H19	0.9500
C4—C5	1.3842 (19)	C20—H20	0.9500
C4—H4	0.9500	C21—C22	1.3882 (18)
C5—C6	1.3945 (18)	C21—C26	1.3901 (18)
C5—H5	0.9500	C22—C23	1.387 (2)
C6—C7	1.3802 (17)	C22—H22	0.9500
C6—H6	0.9500	C23—C24	1.380 (2)
C7—C8	1.5169 (16)	C23—H23	0.9500
C8—C21	1.5084 (16)	C24—C25	1.378 (2)
C8—C9	1.5742 (16)	C24—H24	0.9500
C9—C10	1.5328 (17)	C25—C26	1.384 (2)
C9—C14	1.5494 (16)	C25—H25	0.9500
C9—H9	1.0000	C26—H26	0.9500
C10—C11	1.4896 (19)	C27—C28	1.517 (2)
C10—C28	1.5531 (17)	C27—H27A	0.9900
C11—C12	1.3291 (19)	C27—H27B	0.9900
C11—H11	0.9500	C28—H28A	0.9900
C12—C13	1.4638 (18)	C28—H28B	0.9900
C12—H12	0.9500
C1—O1—C8	98.66 (8)	C13—C14—C1	111.61 (9)
C27—O3—C10	91.53 (9)	C9—C14—C1	101.86 (9)
O1—C1—C15	111.88 (9)	C13—C14—H14	108.7
O1—C1—C2	101.49 (9)	C9—C14—H14	108.7
C15—C1—C2	120.95 (10)	C1—C14—H14	108.7
O1—C1—C14	99.18 (8)	C16—C15—C20	118.63 (11)
C15—C1—C14	114.09 (9)	C16—C15—C1	119.69 (11)
C2—C1—C14	106.44 (9)	C20—C15—C1	121.58 (11)
C3—C2—C7	120.82 (11)	C17—C16—C15	120.37 (13)
C3—C2—C1	133.86 (11)	C17—C16—H16	119.8
C7—C2—C1	104.77 (10)	C15—C16—H16	119.8
C2—C3—C4	117.67 (12)	C18—C17—C16	120.72 (13)
C2—C3—H3	121.2	C18—C17—H17	119.6
C4—C3—H3	121.2	C16—C17—H17	119.6
C5—C4—C3	121.43 (12)	C17—C18—C19	119.48 (13)
C5—C4—H4	119.3	C17—C18—H18	120.3
C3—C4—H4	119.3	C19—C18—H18	120.3
C4—C5—C6	120.74 (12)	C18—C19—C20	120.30 (13)
C4—C5—H5	119.6	C18—C19—H19	119.9
C6—C5—H5	119.6	C20—C19—H19	119.9
C7—C6—C5	117.91 (12)	C19—C20—C15	120.50 (12)
C7—C6—H6	121.0	C19—C20—H20	119.7
C5—C6—H6	121.0	C15—C20—H20	119.7
C6—C7—C2	121.41 (11)	C22—C21—C26	118.17 (12)
C6—C7—C8	132.21 (11)	C22—C21—C8	119.30 (11)
C2—C7—C8	106.01 (10)	C26—C21—C8	122.48 (11)
O1—C8—C21	109.41 (9)	C23—C22—C21	121.02 (13)
O1—C8—C7	100.64 (9)	C23—C22—H22	119.5
C21—C8—C7	118.83 (10)	C21—C22—H22	119.5
O1—C8—C9	99.93 (9)	C24—C23—C22	119.98 (14)
C21—C8—C9	118.55 (10)	C24—C23—H23	120.0
C7—C8—C9	106.38 (9)	C22—C23—H23	120.0
C10—C9—C14	114.88 (10)	C25—C24—C23	119.64 (14)
C10—C9—C8	115.73 (9)	C25—C24—H24	120.2
C14—C9—C8	101.88 (9)	C23—C24—H24	120.2
C10—C9—H9	108.0	C24—C25—C26	120.35 (14)
C14—C9—H9	108.0	C24—C25—H25	119.8
C8—C9—H9	108.0	C26—C25—H25	119.8
O3—C10—C11	111.83 (11)	C25—C26—C21	120.82 (13)
O3—C10—C9	111.08 (10)	C25—C26—H26	119.6
C11—C10—C9	114.12 (10)	C21—C26—H26	119.6
O3—C10—C28	90.19 (9)	O3—C27—C28	92.18 (10)
C11—C10—C28	112.11 (11)	O3—C27—H27A	113.3
C9—C10—C28	115.18 (11)	C28—C27—H27A	113.3
C12—C11—C10	122.86 (12)	O3—C27—H27B	113.3
C12—C11—H11	118.6	C28—C27—H27B	113.3
C10—C11—H11	118.6	H27A—C27—H27B	110.6
C11—C12—C13	120.35 (12)	C27—C28—C10	85.80 (10)
C11—C12—H12	119.8	C27—C28—H28A	114.4
C13—C12—H12	119.8	C10—C28—H28A	114.4
O2—C13—C12	122.18 (12)	C27—C28—H28B	114.4
O2—C13—C14	120.24 (12)	C10—C28—H28B	114.4
C12—C13—C14	117.55 (11)	H28A—C28—H28B	111.5
C13—C14—C9	117.01 (10)
C8—O1—C1—C15	179.44 (9)	C11—C12—C13—C14	25.18 (17)
C8—O1—C1—C2	−50.23 (10)	O2—C13—C14—C9	157.48 (10)
C8—O1—C1—C14	58.76 (9)	C12—C13—C14—C9	−24.54 (14)
O1—C1—C2—C3	−157.19 (13)	O2—C13—C14—C1	−85.78 (13)
C15—C1—C2—C3	−32.77 (19)	C12—C13—C14—C1	92.21 (12)
C14—C1—C2—C3	99.54 (15)	C10—C9—C14—C13	−3.57 (14)
O1—C1—C2—C7	31.60 (11)	C8—C9—C14—C13	122.35 (10)
C15—C1—C2—C7	156.02 (10)	C10—C9—C14—C1	−125.53 (10)
C14—C1—C2—C7	−71.68 (11)	C8—C9—C14—C1	0.38 (11)
C7—C2—C3—C4	−1.47 (18)	O1—C1—C14—C13	−160.98 (9)
C1—C2—C3—C4	−171.57 (12)	C15—C1—C14—C13	79.97 (13)
C2—C3—C4—C5	0.6 (2)	C2—C1—C14—C13	−56.02 (12)
C3—C4—C5—C6	0.7 (2)	O1—C1—C14—C9	−35.36 (10)
C4—C5—C6—C7	−1.10 (19)	C15—C1—C14—C9	−154.42 (10)
C5—C6—C7—C2	0.19 (18)	C2—C1—C14—C9	69.60 (11)
C5—C6—C7—C8	172.23 (12)	O1—C1—C15—C16	−12.96 (15)
C3—C2—C7—C6	1.12 (18)	C2—C1—C15—C16	−132.37 (12)
C1—C2—C7—C6	173.75 (11)	C14—C1—C15—C16	98.62 (13)
C3—C2—C7—C8	−172.75 (11)	O1—C1—C15—C20	170.72 (10)
C1—C2—C7—C8	−0.12 (12)	C2—C1—C15—C20	51.30 (16)
C1—O1—C8—C21	175.70 (9)	C14—C1—C15—C20	−77.71 (14)
C1—O1—C8—C7	49.80 (10)	C20—C15—C16—C17	−0.07 (18)
C1—O1—C8—C9	−59.12 (9)	C1—C15—C16—C17	−176.51 (12)
C6—C7—C8—O1	156.29 (12)	C15—C16—C17—C18	−0.3 (2)
C2—C7—C8—O1	−30.78 (11)	C16—C17—C18—C19	0.7 (2)
C6—C7—C8—C21	36.99 (19)	C17—C18—C19—C20	−0.7 (2)
C2—C7—C8—C21	−150.08 (10)	C18—C19—C20—C15	0.3 (2)
C6—C7—C8—C9	−99.94 (15)	C16—C15—C20—C19	0.09 (18)
C2—C7—C8—C9	72.99 (11)	C1—C15—C20—C19	176.46 (11)
O1—C8—C9—C10	159.55 (10)	O1—C8—C21—C22	−81.31 (14)
C21—C8—C9—C10	−81.81 (13)	C7—C8—C21—C22	33.36 (17)
C7—C8—C9—C10	55.26 (13)	C9—C8—C21—C22	165.13 (11)
O1—C8—C9—C14	34.20 (10)	O1—C8—C21—C26	96.14 (14)
C21—C8—C9—C14	152.84 (10)	C7—C8—C21—C26	−149.19 (12)
C7—C8—C9—C14	−70.09 (11)	C9—C8—C21—C26	−17.43 (17)
C27—O3—C10—C11	−118.22 (12)	C26—C21—C22—C23	1.2 (2)
C27—O3—C10—C9	113.00 (11)	C8—C21—C22—C23	178.78 (13)
C27—O3—C10—C28	−4.21 (11)	C21—C22—C23—C24	−0.4 (2)
C14—C9—C10—O3	158.28 (9)	C22—C23—C24—C25	−0.8 (2)
C8—C9—C10—O3	39.89 (14)	C23—C24—C25—C26	1.0 (2)
C14—C9—C10—C11	30.73 (14)	C24—C25—C26—C21	−0.2 (2)
C8—C9—C10—C11	−87.65 (13)	C22—C21—C26—C25	−0.9 (2)
C14—C9—C10—C28	−101.05 (12)	C8—C21—C26—C25	−178.41 (13)
C8—C9—C10—C28	140.56 (11)	C10—O3—C27—C28	4.32 (12)
O3—C10—C11—C12	−160.88 (12)	O3—C27—C28—C10	−4.08 (11)
C9—C10—C11—C12	−33.72 (17)	O3—C10—C28—C27	4.04 (11)
C28—C10—C11—C12	99.53 (15)	C11—C10—C28—C27	117.80 (13)
C10—C11—C12—C13	5.06 (19)	C9—C10—C28—C27	−109.48 (13)
C11—C12—C13—O2	−156.88 (13)