A norbornenyl derivative with through-space ketone π-interaction

The title compound, endo,exo-12-oxotetra­cyclo­[6.2.1.1^3,6.0^2,7]­dodeca-9-en-anti-11-yl p-bromo­benzoate, C₁₉H₁₇BrO₃, con­sists of norbornene with an anti-p-bromo­benzoate substituent at the methano bridge and an exo-fused norbornanone unit bonded to the ethano bridge. The spatially proximate ketone and alkene interact through space and the ketone C atom is substantially pyramidalized. Through-space ketone π-inter­action is probably responsible for the low solvolysis rate of the anti-11-chloride derivative.

Computing details

Data collection: COLLECT; cell refinement: DENZO-SMN; data reduction: DENZO-SMN; program(s) used to solve structure: SIR97; program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: WinGX (Farrugia, 1998) and ORTEP-3 (Farrugia, 1997).

(1-OPBB)

Crystal data

C19H17BrO3	F(000) = 760
Mr = 373.24	Dx = 1.55 Mg m^−3
Monoclinic, P21/a	Mo Kα radiation, λ = 0.71073 Å
a = 11.3936 (3) Å	Cell parameters from 17290 reflections
b = 8.2659 (2) Å	θ = 4.4–32.6°
c = 16.9840 (5) Å	µ = 2.58 mm^−1
β = 90.6750 (17)°	T = 148 K
V = 1599.41 (7) Å^3	Prism, colorless
Z = 4	0.3 × 0.23 × 0.2 mm

Data collection

Nonius KappaCCD Diffractometer	4073 reflections with I > 2σ(I)
Phi Scan scans	Rint = 0.023
Absorption correction: multi-scan DENZO-SMN (Otwinowski & Minor, 1997)	θmax = 32.6°, θmin = 4.4°
Tmin = 0.511, Tmax = 0.626	h = −16→17
8643 measured reflections	k = −10→12
5678 independent reflections	l = −25→25

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.041	w = 1/[σ^2(Fo^2) + (0.0168P)^2 + 1.2341P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.090	(Δ/σ)max = 0.001
S = 1.01	Δρmax = 0.59 e Å^−3
5678 reflections	Δρmin = −0.50 e Å^−3
276 parameters

Special details

Experimental. The dimethoxy ketal of (1-(OCH₃)₂) was hydrolyzed in a manner similar to literature methods (Bertsch et al., 1988; Fessner et al., 1987; Gassman & Marshall, 1973), by stirring (1-(OCH₃)₂) in a 1:1 solution of 27%(w/w) HClO₄ and THF at 298 K for 3 h. Solid NaHCO₃ was then added until the mixture was no longer acidic. The mixture was extracted five times with CH₂Cl₂, shaking gently to avoid emulsion formation. The CH₂Cl₂ extracts were combined and washed once with saturated brine. The brine layer was extracted four times with CH₂Cl₂ and the CH₂Cl₂ extracts were combined. After evaporation of the solvents, and purification by column chromatography (silica, CH₂Cl₂ solvent), white crystalline diketone (1═O) was isolated (88%): mp 358–359 K, ¹H NMR (90 MHz, CDCl₃) δ 1.57–1.80 (m, 4 H), 1.88 (m, 2 H), 2.56 (m, 2 H) 3.14 (m, 2 H), 6.42 (t, 2 H). IR (CDCl ₃) 3020 s h, 2950 m, 2882 m, 1805 s h, 1763 s, 1746 s h, 1130 m, 915 s cm^-1. # #Insert structure diagram 2 for synthesis here.# #

The C11═O ketone was reduced (Cieplak, 1999; Ohwada, 1999, and references therein) selectively in preference to the C12═O ketone to the anti-alcohol (1-OH) with LiAlH(O—C(CH₃)₃). Diketone (1═ O) was dried (13 torr, over CaH₂, 24 h). To a stirred 4.2%(w/w) solution of LiAlH₄ in dry THF were slowly added 3 moles of t-butanol at 273 K. After stirring for 10 min, a cooled (273 K) 14%(w/w) solution of diketone (1═O) in THF was added over 5 min at 273 K under N₂. The LiAlH(O—C(CH₃)₃) was in a 20% molar excess. Stirring was continued as the mixture was allowed to slowly warm up to 298 K. A basic workup was then used (Fieser & Feiser, 1967). The aluminium salts were removed by vacuum filtration, and the THF solution was concentrated in vacuo. The product was purified by column chromatography (Florisil, THF solvent), yielding initially a colorless oil that crystallized on standing (1-OH) (92%): mp 351–353 K, ¹H NMR (300 MHz, acetone-d₆) δ 1.48–1.60 (m, 2 H), 1.62–1.66 (m, 2 H), 1.70 (m, 2 H), 2.46 (m, 2 H), 2.71 (m, 2 H), 3.56 (m, 1 H), 4.53 (m, 1 H), 5.82 (t, 2 H). ¹³C NMR (75 MHz, proton decoupled, acetone-d₆) δ 23.06, 41.59, 43.14, 50.66, 84.59, 135.62, 215.26. IR (CDCl₃), 3700–3100 s, 3060 w, 2975 s, 2876 m, 1760 s, 1733 s, 1240 m, 1085 s, 910 m cm^-1.

Alcohol (1-OH) was esterified by reaction with an equimolar amount of p-bromobenzoyl chloride in a 2.05: 1 molar excess of pyridine with CH₂Cl₂ solvent. All materials were dry, and the mixture was warmed to reflux for 20 min. The reaction mixture was poured into cold 5% HCl, and extracted with CH₂Cl₂. The CH₂Cl₂ extracts were washed twice more with 5% HCl, and then with saturated brine. The CH₂Cl₂ layer was dried (MgSO₄), filtered, and CH₂Cl₂ was evaporated. Column chromatography (Florisil, ether solvent), yielded white crystals (83%). Purity was further improved by recrystallizing three times from CH₂Cl₂ / ether, yielding colorless prisms: mp 448–449 K, ¹H NMR (90 MHz, CDCl₃) δ 1.36–1.80 (m, 4 H), 1.86 (m, 2 H), 2.44 (m, 2 H), 3.13 (m, 2 H), 4.61 (m, 1 H), 6.03 (t, 2 H), 7.59 (d, 2 H), 7.88 (m, 2 H).

Alcohol (1-OH) was converted to the chloride (1-Cl) by reaction with triphenylphosphine in carbon tetrachloride (Ashby et al., 1984; Calzada & Hooz, 1974). Triphenylphosphine was recrystallized from ether/pentane and dried over P₂O₅ under vacuum before use. Alcohol (1-OH was sublimed at 373–423 K (3 Pa). Equimolar amounts of (1-OH) and triphenylphosphine were flame sealed in a 23 fold molar excess of CCl₄ in a 5 mm glass NMR tube under N₂. The reaction was followed by ¹H NMR spectroscopy. Quantitative conversion was observed after heating for 2 h at 393 K. The literature workup was followed, i.e., addition of pentane, cooling to 273 K, and filtration. The filtrate was concentrated and chromatographed on Florisil, the product eluting in ether. Evaporation of solvent yielded white crystals (72%). Product was purified further by preparative gas chromatography (2 m × 0.5 cm stainless steel, 3% SE-30 on Chrom W NAW, He carrier). White crystals were collected, mp 370–371 K, ¹H NMR (300 MHz, CDCl₃) δ 1.52–1.56 (m, 2H), 1.74–1.78 (m, 2H), 1.85 (m, 2H), 2.61 (m, 2H), 2.97 (m, 2H), 3.79 (m,1H), 6.06 (t, 2H).

The program DENZO-SMN (Otwinowski & Minor, 1997) uses a scaling algorithm (Fox & Holmes, 1966) which effectively corrects for absorption effects. High redundancy data were used in the scaling program hence the 'multi-scan' code word was used. No transmission coefficients are available from the program (only scale factors for each frame). The scale factors in the experimental table are calculated from the 'size' command in the SHELXL97 input file.

Ashby, E. C., DePriest, R. N., Goel, A. B., Wenderoth, B., Pham, T. N. (1984). J. Org. Chem. 49, 3545–3556.

Bertsch, A., Grimme, W., Reinhardt, G., Rose, H., and Warner, P. M. (1988). J. Am. Chem. Soc. 110, 5112–5117.

Calzada, J. G. and Hooz, J. (1974). Organic Syntheses, 54, 63–67.

Fessner, W.-D., Sedelmeier, G., Spurr, P. R., Rihs, G. and Prinzbach, H. (1987). J. Am. Chem. Soc. 109, 4626–4642.

Feiser, L. F. & Feiser, M. (1967). Reagents for Organic Synthesis, Vol. 1, pp 583–584, John Wiley and Sons: New York.

Gassman, P. G. and Marshall, J. L. (1973). Org. Synth. Coll. Vol. V, pp. 91–92, 424–428.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.02746 (2)	0.11759 (3)	0.317324 (12)	0.04828 (8)
O1	0.30432 (13)	−0.05847 (19)	1.00623 (8)	0.0411 (3)
O2	0.45118 (11)	0.0937 (2)	0.60835 (8)	0.0407 (3)
O3	0.29321 (10)	0.17207 (16)	0.67655 (7)	0.0281 (3)
C1	0.29256 (15)	0.2448 (2)	0.81580 (10)	0.0268 (3)
H1	0.2540 (19)	0.352 (3)	0.8111 (13)	0.037 (6)*
C2	0.20800 (14)	0.0979 (2)	0.82345 (10)	0.0247 (3)
H2	0.1442 (18)	0.109 (2)	0.7871 (12)	0.028 (5)*
C3	0.16542 (15)	0.0540 (2)	0.90637 (10)	0.0295 (4)
H3	0.1408 (19)	0.143 (3)	0.9396 (13)	0.037 (6)*
C4	0.07566 (18)	−0.0844 (3)	0.89535 (12)	0.0392 (5)
H4A	0.037 (2)	−0.111 (3)	0.9421 (14)	0.040 (6)*
H4B	0.0167 (19)	−0.056 (3)	0.8555 (14)	0.038 (6)*
C5	0.1525 (2)	−0.2319 (3)	0.87059 (13)	0.0432 (5)
H5A	0.148 (2)	−0.318 (3)	0.9078 (15)	0.055 (7)*
H5B	0.132 (2)	−0.277 (3)	0.8192 (14)	0.046 (6)*
C6	0.27929 (18)	−0.1646 (2)	0.87042 (11)	0.0337 (4)
H6	0.338 (2)	−0.238 (3)	0.8757 (13)	0.041 (6)*
C7	0.28821 (15)	−0.0495 (2)	0.80002 (10)	0.0262 (3)
H7	0.2616 (16)	−0.100 (2)	0.7532 (11)	0.021 (5)*
C8	0.40863 (15)	0.0327 (2)	0.78465 (10)	0.0277 (3)
H8	0.4600 (18)	−0.034 (3)	0.7551 (12)	0.032 (5)*
C9	0.45407 (16)	0.1045 (2)	0.86126 (11)	0.0312 (4)
H9	0.515 (2)	0.062 (3)	0.8934 (14)	0.042 (6)*
C10	0.38586 (16)	0.2291 (2)	0.87942 (11)	0.0298 (4)
H10	0.3879 (18)	0.295 (3)	0.9260 (13)	0.034 (5)*
C11	0.36713 (15)	0.1911 (2)	0.74588 (10)	0.0271 (3)
H11	0.4299 (19)	0.265 (3)	0.7347 (12)	0.035 (6)*
C12	0.26467 (16)	−0.0498 (2)	0.93999 (10)	0.0312 (4)
C13	0.34773 (16)	0.1254 (2)	0.61032 (10)	0.0286 (3)
C14	0.26720 (15)	0.1199 (2)	0.54091 (10)	0.0274 (3)
C15	0.15020 (17)	0.1651 (3)	0.54608 (11)	0.0337 (4)
H15	0.121 (2)	0.198 (3)	0.5945 (14)	0.042 (6)*
C16	0.07909 (19)	0.1641 (3)	0.47929 (12)	0.0378 (4)
H16	0.001 (2)	0.192 (3)	0.4831 (15)	0.053 (7)*
C17	0.12596 (18)	0.1177 (2)	0.40830 (11)	0.0337 (4)
C18	0.2419 (2)	0.0714 (3)	0.40175 (12)	0.0385 (4)
H18	0.272 (2)	0.036 (3)	0.3561 (15)	0.055 (7)*
C19	0.31248 (18)	0.0719 (3)	0.46895 (11)	0.0354 (4)
H19	0.392 (2)	0.040 (3)	0.4651 (14)	0.046 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.07021 (17)	0.04111 (12)	0.03298 (11)	−0.00157 (11)	−0.02163 (10)	0.00000 (9)
O1	0.0454 (8)	0.0470 (8)	0.0304 (7)	−0.0117 (7)	−0.0158 (6)	0.0095 (6)
O2	0.0255 (6)	0.0644 (10)	0.0322 (7)	0.0014 (7)	0.0023 (5)	−0.0046 (7)
O3	0.0253 (6)	0.0376 (7)	0.0214 (5)	0.0021 (5)	−0.0005 (4)	0.0006 (5)
C1	0.0290 (8)	0.0256 (8)	0.0258 (8)	0.0016 (7)	−0.0007 (6)	−0.0015 (6)
C2	0.0206 (7)	0.0317 (9)	0.0218 (7)	0.0007 (6)	−0.0035 (6)	0.0012 (6)
C3	0.0263 (8)	0.0385 (10)	0.0236 (8)	−0.0020 (8)	−0.0037 (6)	0.0020 (7)
C4	0.0311 (9)	0.0573 (13)	0.0291 (9)	−0.0142 (9)	−0.0055 (8)	0.0100 (9)
C5	0.0528 (13)	0.0381 (11)	0.0384 (11)	−0.0203 (10)	−0.0179 (10)	0.0109 (9)
C6	0.0378 (10)	0.0283 (8)	0.0346 (9)	0.0002 (8)	−0.0146 (8)	0.0045 (7)
C7	0.0275 (8)	0.0245 (8)	0.0264 (8)	−0.0004 (7)	−0.0076 (6)	−0.0010 (6)
C8	0.0234 (8)	0.0327 (9)	0.0270 (8)	0.0049 (7)	−0.0036 (6)	−0.0041 (7)
C9	0.0256 (8)	0.0392 (10)	0.0287 (8)	−0.0035 (8)	−0.0068 (7)	0.0000 (7)
C10	0.0314 (9)	0.0320 (9)	0.0259 (8)	−0.0069 (7)	−0.0026 (7)	−0.0037 (7)
C11	0.0234 (8)	0.0330 (9)	0.0249 (8)	−0.0029 (7)	−0.0010 (6)	−0.0007 (7)
C12	0.0324 (9)	0.0339 (9)	0.0271 (8)	−0.0099 (8)	−0.0080 (7)	0.0069 (7)
C13	0.0273 (8)	0.0332 (9)	0.0255 (8)	−0.0027 (7)	0.0032 (6)	0.0002 (7)
C14	0.0288 (8)	0.0292 (8)	0.0241 (7)	−0.0024 (7)	0.0002 (6)	−0.0002 (6)
C15	0.0326 (9)	0.0415 (10)	0.0269 (8)	0.0042 (8)	−0.0016 (7)	−0.0033 (8)
C16	0.0363 (10)	0.0439 (11)	0.0332 (9)	0.0062 (9)	−0.0066 (8)	−0.0036 (8)
C17	0.0467 (11)	0.0276 (8)	0.0264 (8)	−0.0036 (8)	−0.0094 (7)	0.0001 (7)
C18	0.0480 (12)	0.0425 (10)	0.0250 (8)	−0.0041 (9)	0.0038 (8)	−0.0064 (8)
C19	0.0338 (10)	0.0417 (10)	0.0307 (9)	−0.0007 (9)	0.0039 (7)	−0.0059 (8)

Geometric parameters (Å, º)

Br1—C17	1.8989 (18)	C6—C7	1.532 (3)
O1—C12	1.210 (2)	C6—H6	0.91 (2)
O2—C13	1.208 (2)	C7—C8	1.556 (2)
O3—C13	1.348 (2)	C7—H7	0.944 (19)
O3—C11	1.448 (2)	C8—C9	1.516 (2)
C1—C10	1.512 (2)	C8—C11	1.537 (3)
C1—C11	1.534 (2)	C8—H8	0.95 (2)
C1—C2	1.557 (2)	C9—C10	1.328 (3)
C1—H1	0.99 (2)	C9—H9	0.94 (2)
C2—C3	1.538 (2)	C10—H10	0.96 (2)
C2—C7	1.577 (2)	C11—H11	0.96 (2)
C2—H2	0.95 (2)	C13—C14	1.486 (2)
C3—C12	1.525 (3)	C14—C15	1.388 (3)
C3—C4	1.545 (3)	C14—C19	1.390 (3)
C3—H3	0.97 (2)	C15—C16	1.386 (3)
C4—C5	1.561 (3)	C15—H15	0.93 (2)
C4—H4A	0.94 (2)	C16—C17	1.379 (3)
C4—H4B	0.98 (2)	C16—H16	0.93 (3)
C5—C6	1.548 (3)	C17—C18	1.381 (3)
C5—H5A	0.95 (3)	C18—C19	1.388 (3)
C5—H5B	0.97 (2)	C18—H18	0.90 (3)
C6—C12	1.526 (3)	C19—H19	0.95 (2)
C13—O3—C11	116.12 (13)	C9—C8—C11	97.73 (14)
C10—C1—C11	97.88 (14)	C9—C8—C7	108.66 (14)
C10—C1—C2	107.69 (14)	C11—C8—C7	100.16 (13)
C11—C1—C2	100.82 (14)	C9—C8—H8	118.3 (12)
C10—C1—H1	116.2 (13)	C11—C8—H8	117.0 (13)
C11—C1—H1	116.5 (13)	C7—C8—H8	112.7 (13)
C2—C1—H1	115.4 (13)	C10—C9—C8	107.93 (16)
C3—C2—C1	117.55 (14)	C10—C9—H9	125.5 (14)
C3—C2—C7	103.82 (14)	C8—C9—H9	126.2 (14)
C1—C2—C7	102.75 (13)	C9—C10—C1	107.99 (15)
C3—C2—H2	111.7 (12)	C9—C10—H10	128.5 (13)
C1—C2—H2	110.0 (12)	C1—C10—H10	123.3 (13)
C7—C2—H2	110.4 (12)	O3—C11—C1	109.80 (13)
C12—C3—C2	103.59 (14)	O3—C11—C8	115.40 (14)
C12—C3—C4	96.62 (15)	C1—C11—C8	94.89 (14)
C2—C3—C4	106.21 (15)	O3—C11—H11	109.6 (12)
C12—C3—H3	115.2 (13)	C1—C11—H11	113.0 (13)
C2—C3—H3	116.8 (13)	C8—C11—H11	113.5 (13)
C4—C3—H3	115.8 (13)	O1—C12—C3	130.44 (19)
C3—C4—C5	103.82 (16)	O1—C12—C6	129.82 (19)
C3—C4—H4A	112.7 (14)	C3—C12—C6	98.47 (14)
C5—C4—H4A	108.2 (14)	O2—C13—O3	123.00 (16)
C3—C4—H4B	110.6 (14)	O2—C13—C14	124.38 (16)
C5—C4—H4B	112.7 (14)	O3—C13—C14	112.61 (15)
H4A—C4—H4B	108.8 (19)	C15—C14—C19	119.94 (17)
C6—C5—C4	104.24 (16)	C15—C14—C13	121.73 (16)
C6—C5—H5A	108.9 (15)	C19—C14—C13	118.31 (16)
C4—C5—H5A	111.8 (16)	C16—C15—C14	119.93 (18)
C6—C5—H5B	110.1 (14)	C16—C15—H15	120.6 (14)
C4—C5—H5B	114.3 (14)	C14—C15—H15	119.5 (14)
H5A—C5—H5B	107 (2)	C17—C16—C15	119.25 (19)
C12—C6—C7	103.11 (15)	C17—C16—H16	121.0 (15)
C12—C6—C5	96.41 (17)	C15—C16—H16	119.7 (16)
C7—C6—C5	107.16 (15)	C16—C17—C18	121.88 (18)
C12—C6—H6	115.2 (14)	C16—C17—Br1	118.71 (16)
C7—C6—H6	115.7 (15)	C18—C17—Br1	119.41 (15)
C5—C6—H6	116.8 (15)	C17—C18—C19	118.57 (18)
C6—C7—C8	117.96 (14)	C17—C18—H18	122.4 (16)
C6—C7—C2	103.82 (15)	C19—C18—H18	119.0 (16)
C8—C7—C2	102.70 (13)	C18—C19—C14	120.42 (19)
C6—C7—H7	111.1 (11)	C18—C19—H19	119.2 (14)
C8—C7—H7	109.0 (12)	C14—C19—H19	120.4 (14)
C2—C7—H7	111.8 (11)
C10—C1—C2—C3	45.9 (2)	C10—C1—C11—O3	171.73 (14)
C11—C1—C2—C3	147.84 (15)	C2—C1—C11—O3	61.93 (16)
C10—C1—C2—C7	−67.36 (16)	C10—C1—C11—C8	52.49 (15)
C11—C1—C2—C7	34.62 (15)	C2—C1—C11—C8	−57.31 (14)
C1—C2—C3—C12	−83.66 (18)	C9—C8—C11—O3	−167.03 (14)
C7—C2—C3—C12	28.96 (17)	C7—C8—C11—O3	−56.39 (17)
C1—C2—C3—C4	175.17 (15)	C9—C8—C11—C1	−52.38 (15)
C7—C2—C3—C4	−72.21 (17)	C7—C8—C11—C1	58.25 (14)
C12—C3—C4—C5	−35.88 (17)	C2—C3—C12—O1	143.5 (2)
C2—C3—C4—C5	70.38 (18)	C4—C3—C12—O1	−108.0 (2)
C3—C4—C5—C6	0.47 (19)	C2—C3—C12—C6	−48.63 (17)
C4—C5—C6—C12	35.09 (18)	C4—C3—C12—C6	59.86 (16)
C4—C5—C6—C7	−70.79 (19)	C7—C6—C12—O1	−142.0 (2)
C12—C6—C7—C8	80.40 (19)	C5—C6—C12—O1	108.6 (2)
C5—C6—C7—C8	−178.53 (16)	C7—C6—C12—C3	49.99 (17)
C12—C6—C7—C2	−32.36 (17)	C5—C6—C12—C3	−59.33 (16)
C5—C6—C7—C2	68.70 (18)	C11—O3—C13—O2	3.2 (3)
C3—C2—C7—C6	2.08 (16)	C11—O3—C13—C14	−176.03 (14)
C1—C2—C7—C6	125.03 (14)	O2—C13—C14—C15	−176.83 (19)
C3—C2—C7—C8	−121.31 (14)	O3—C13—C14—C15	2.3 (3)
C1—C2—C7—C8	1.64 (15)	O2—C13—C14—C19	1.4 (3)
C6—C7—C8—C9	−48.8 (2)	O3—C13—C14—C19	−179.39 (17)
C2—C7—C8—C9	64.60 (17)	C19—C14—C15—C16	−0.7 (3)
C6—C7—C8—C11	−150.60 (16)	C13—C14—C15—C16	177.53 (19)
C2—C7—C8—C11	−37.21 (15)	C14—C15—C16—C17	0.1 (3)
C11—C8—C9—C10	34.21 (18)	C15—C16—C17—C18	0.2 (3)
C7—C8—C9—C10	−69.31 (19)	C15—C16—C17—Br1	−179.83 (16)
C8—C9—C10—C1	0.1 (2)	C16—C17—C18—C19	0.1 (3)
C11—C1—C10—C9	−34.40 (19)	Br1—C17—C18—C19	−179.83 (16)
C2—C1—C10—C9	69.67 (19)	C17—C18—C19—C14	−0.7 (3)
C13—O3—C11—C1	179.81 (15)	C15—C14—C19—C18	1.1 (3)
C13—O3—C11—C8	−74.45 (19)	C13—C14—C19—C18	−177.24 (18)