Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199015309/gs1062sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270199015309/gs1062Isup2.hkl |
CCDC reference: 143258
1626 Friedel pairs were measured. Absolute configuration was not established by anomalous dispersion effects. The enantiomer has been assigned by reference to an unchanging chiral centre in the synthetic procedure.
Data collection: CAD-4 Software (Enraf-Nonius, 1987); cell refinement: CAD-4 Software; data reduction: NONIUS (Riche, 1989); program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: R3M (Riche, 1983) and ORTEP (Johnson, 1963).
Fig. 1. ORTEP (Johnson, 1965) plot of (III) with atom numbering. Ellipsoids are set at the 30% probability level |
C20H28O8 | Dx = 1.235 Mg m−3 |
Mr = 396.42 | Melting point: 128.2 _C K |
Monoclinic, P21 | Cu Kα radiation, λ = 1.54180 Å |
a = 8.869 (2) Å | Cell parameters from 25 reflections |
b = 9.836 (2) Å | θ = 12.9–18.7° |
c = 12.225 (6) Å | µ = 0.80 mm−1 |
β = 91.40 (3)° | T = 293 K |
V = 1066.1 (6) Å3 | Prism, colourless |
Z = 2 | 0.50 × 0.30 × 0.30 mm |
F(000) = 424 |
Nonius CAD4 diffractometer | Rint = 0.050 |
Radiation source: fine-focus sealed tube | θmax = 66.9°, θmin = 3.6° |
Graphite monochromator | h = −10→10 |
θ/2θ scans | k = −11→11 |
4755 measured reflections | l = −10→14 |
3601 independent reflections | 3 standard reflections every 120 min |
3430 reflections with I > 2σ(I) | intensity decay: 2% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
wR(F2) = 0.108 | Calculated w = 1/[σ2(Fo2) + (0.0707P)2 + 0.0992P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.018 |
3601 reflections | Δρmax = 0.20 e Å−3 |
255 parameters | Δρmin = −0.20 e Å−3 |
1 restraint | Extinction correction: SHELXL93 (Sheldrick, 1993), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0211 (15) |
C20H28O8 | V = 1066.1 (6) Å3 |
Mr = 396.42 | Z = 2 |
Monoclinic, P21 | Cu Kα radiation |
a = 8.869 (2) Å | µ = 0.80 mm−1 |
b = 9.836 (2) Å | T = 293 K |
c = 12.225 (6) Å | 0.50 × 0.30 × 0.30 mm |
β = 91.40 (3)° |
Nonius CAD4 diffractometer | Rint = 0.050 |
4755 measured reflections | 3 standard reflections every 120 min |
3601 independent reflections | intensity decay: 2% |
3430 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.040 | 1 restraint |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.20 e Å−3 |
3601 reflections | Δρmin = −0.20 e Å−3 |
255 parameters |
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 on F2 for ALL reflections except for 0 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_obs 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 | ||
C1 | −0.0911 (2) | 0.0373 (2) | 0.77730 (15) | 0.0374 (4) | |
C2 | −0.0441 (2) | 0.1769 (2) | 0.8151 (2) | 0.0412 (4) | |
C3 | −0.0776 (2) | 0.1960 (2) | 0.9188 (2) | 0.0489 (5) | |
H3 | −0.0574 (2) | 0.2762 (2) | 0.9567 (2) | 0.059* | |
C4 | −0.1517 (2) | 0.0748 (2) | 0.9690 (2) | 0.0450 (4) | |
H4 | −0.0922 (2) | 0.0426 (2) | 1.0324 (2) | 0.054* | |
C5 | −0.1520 (2) | −0.0301 (2) | 0.87907 (15) | 0.0400 (4) | |
H5 | −0.2387 (2) | −0.0914 (2) | 0.87115 (15) | 0.048* | |
C6 | −0.0038 (2) | −0.0753 (2) | 0.83816 (14) | 0.0382 (4) | |
H6 | 0.0841 (2) | −0.0445 (2) | 0.88148 (14) | 0.046* | |
C7 | −0.1508 (2) | 0.0184 (2) | 0.6646 (2) | 0.0431 (4) | |
O8 | −0.1896 (2) | −0.1086 (2) | 0.64240 (13) | 0.0600 (4) | |
HO8 | −0.2194 (2) | −0.1141 (2) | 0.57851 (13) | 0.081 (9)* | |
O9 | −0.1629 (3) | 0.1081 (2) | 0.59943 (14) | 0.0787 (6) | |
C10 | 0.0429 (2) | 0.2694 (2) | 0.7438 (2) | 0.0479 (5) | |
H10A | −0.0197 (2) | 0.3024 (2) | 0.6833 (2) | 0.058* | |
H10B | 0.0815 (2) | 0.3465 (2) | 0.7852 (2) | 0.058* | |
O11 | 0.1649 (2) | 0.18663 (15) | 0.70465 (12) | 0.0515 (4) | |
C12 | 0.2374 (2) | 0.2267 (2) | 0.6167 (2) | 0.0479 (5) | |
O13 | 0.2115 (2) | 0.3354 (2) | 0.57380 (14) | 0.0696 (5) | |
C14 | 0.3456 (3) | 0.1210 (3) | 0.5766 (2) | 0.0584 (6) | |
C15 | 0.4674 (4) | 0.1887 (5) | 0.5104 (3) | 0.1082 (13) | |
H15A | 0.5361 (4) | 0.1210 (5) | 0.4849 (3) | 0.162* | |
H15B | 0.5213 (4) | 0.2531 (5) | 0.5556 (3) | 0.162* | |
H15C | 0.4218 (4) | 0.2349 (5) | 0.4488 (3) | 0.162* | |
C16 | 0.4187 (3) | 0.0424 (4) | 0.6714 (3) | 0.0842 (9) | |
H16A | 0.4868 (3) | −0.0241 (4) | 0.6432 (3) | 0.126* | |
H16B | 0.3419 (3) | −0.0024 (4) | 0.7120 (3) | 0.126* | |
H16C | 0.4732 (3) | 0.1042 (4) | 0.7185 (3) | 0.126* | |
C17 | 0.2516 (4) | 0.0235 (4) | 0.5048 (3) | 0.1015 (11) | |
H17A | 0.3157 (4) | −0.0464 (4) | 0.4769 (3) | 0.152* | |
H17B | 0.2059 (4) | 0.0728 (4) | 0.4449 (3) | 0.152* | |
H17C | 0.1743 (4) | −0.0171 (4) | 0.5476 (3) | 0.152* | |
O18 | −0.3029 (2) | 0.1104 (2) | 1.00098 (12) | 0.0512 (4) | |
C19 | −0.3685 (2) | 0.0229 (2) | 1.0707 (2) | 0.0471 (5) | |
O20 | −0.3041 (2) | −0.0782 (2) | 1.1025 (2) | 0.0702 (5) | |
C21 | −0.5253 (2) | 0.0666 (2) | 1.1027 (2) | 0.0529 (5) | |
C22 | −0.5878 (4) | −0.0405 (4) | 1.1798 (4) | 0.1093 (14) | |
H22A | −0.5224 (4) | −0.0484 (4) | 1.2432 (4) | 0.164* | |
H22B | −0.5937 (4) | −0.1264 (4) | 1.1427 (4) | 0.164* | |
H22C | −0.6867 (4) | −0.0138 (4) | 1.2018 (4) | 0.164* | |
C23 | −0.5132 (3) | 0.2031 (3) | 1.1615 (3) | 0.0782 (8) | |
H23A | −0.4494 (3) | 0.1937 (3) | 1.2257 (3) | 0.117* | |
H23B | −0.6117 (3) | 0.2322 (3) | 1.1824 (3) | 0.117* | |
H23C | −0.4708 (3) | 0.2694 (3) | 1.1135 (3) | 0.117* | |
C24 | −0.6253 (3) | 0.0817 (5) | 1.0022 (3) | 0.0954 (11) | |
H24A | −0.7242 (3) | 0.1093 (5) | 1.0233 (3) | 0.143* | |
H24B | −0.6317 (3) | −0.0038 (5) | 0.9644 (3) | 0.143* | |
H24C | −0.5837 (3) | 0.1491 (5) | 0.9548 (3) | 0.143* | |
C25 | 0.0095 (2) | −0.2157 (2) | 0.7905 (2) | 0.0409 (4) | |
O26 | −0.0663 (2) | −0.3108 (2) | 0.81357 (14) | 0.0623 (4) | |
O27 | 0.1220 (2) | −0.21990 (15) | 0.72120 (13) | 0.0542 (4) | |
C28 | 0.1418 (3) | −0.3480 (3) | 0.6647 (2) | 0.0694 (7) | |
H28A | 0.2255 (3) | −0.3410 (3) | 0.6167 (2) | 0.104* | |
H28B | 0.0519 (3) | −0.3691 (3) | 0.6228 (2) | 0.104* | |
H28C | 0.1612 (3) | −0.4188 (3) | 0.7173 (2) | 0.104* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0353 (8) | 0.0411 (9) | 0.0359 (9) | −0.0014 (7) | 0.0038 (7) | −0.0029 (7) |
C2 | 0.0426 (9) | 0.0392 (9) | 0.0418 (9) | −0.0018 (7) | 0.0022 (8) | −0.0028 (8) |
C3 | 0.0555 (11) | 0.0464 (10) | 0.0450 (11) | −0.0060 (9) | 0.0065 (9) | −0.0111 (9) |
C4 | 0.0444 (10) | 0.0540 (11) | 0.0369 (9) | 0.0022 (8) | 0.0078 (8) | −0.0038 (8) |
C5 | 0.0377 (9) | 0.0451 (9) | 0.0376 (10) | −0.0028 (7) | 0.0059 (7) | −0.0031 (8) |
C6 | 0.0383 (8) | 0.0415 (9) | 0.0348 (9) | −0.0004 (7) | 0.0020 (7) | 0.0000 (7) |
C7 | 0.0411 (9) | 0.0497 (10) | 0.0385 (10) | −0.0012 (8) | −0.0014 (8) | −0.0036 (8) |
O8 | 0.0753 (10) | 0.0555 (9) | 0.0483 (8) | −0.0044 (8) | −0.0158 (7) | −0.0104 (7) |
O9 | 0.117 (2) | 0.0672 (10) | 0.0506 (9) | −0.0123 (11) | −0.0280 (10) | 0.0097 (9) |
C10 | 0.0507 (10) | 0.0422 (10) | 0.0514 (11) | −0.0031 (9) | 0.0081 (9) | 0.0003 (9) |
O11 | 0.0498 (7) | 0.0501 (7) | 0.0551 (8) | 0.0027 (6) | 0.0131 (6) | 0.0135 (7) |
C12 | 0.0482 (10) | 0.0547 (11) | 0.0409 (10) | −0.0048 (9) | 0.0036 (9) | 0.0094 (9) |
O13 | 0.0930 (12) | 0.0599 (9) | 0.0567 (9) | 0.0122 (9) | 0.0173 (9) | 0.0224 (8) |
C14 | 0.0467 (11) | 0.0698 (14) | 0.0593 (13) | 0.0076 (10) | 0.0146 (10) | 0.0169 (11) |
C15 | 0.071 (2) | 0.135 (3) | 0.120 (3) | 0.025 (2) | 0.047 (2) | 0.057 (3) |
C16 | 0.068 (2) | 0.100 (2) | 0.085 (2) | 0.028 (2) | 0.0116 (14) | 0.032 (2) |
C17 | 0.097 (2) | 0.107 (2) | 0.100 (2) | 0.031 (2) | 0.003 (2) | −0.040 (2) |
O18 | 0.0525 (8) | 0.0549 (8) | 0.0469 (8) | 0.0101 (6) | 0.0170 (6) | 0.0025 (6) |
C19 | 0.0481 (10) | 0.0538 (11) | 0.0397 (10) | 0.0046 (9) | 0.0076 (8) | −0.0018 (8) |
O20 | 0.0585 (9) | 0.0678 (10) | 0.0848 (12) | 0.0141 (9) | 0.0148 (8) | 0.0243 (10) |
C21 | 0.0484 (11) | 0.0612 (12) | 0.0497 (11) | 0.0058 (9) | 0.0136 (9) | −0.0025 (10) |
C22 | 0.087 (2) | 0.093 (2) | 0.150 (3) | 0.016 (2) | 0.067 (2) | 0.034 (2) |
C23 | 0.0684 (15) | 0.079 (2) | 0.088 (2) | 0.0189 (14) | 0.0143 (14) | −0.023 (2) |
C24 | 0.0542 (14) | 0.149 (3) | 0.083 (2) | 0.018 (2) | −0.0076 (13) | −0.030 (2) |
C25 | 0.0419 (9) | 0.0436 (10) | 0.0373 (9) | 0.0018 (8) | 0.0022 (8) | −0.0004 (8) |
O26 | 0.0705 (10) | 0.0454 (8) | 0.0718 (10) | −0.0101 (7) | 0.0190 (8) | −0.0018 (7) |
O27 | 0.0510 (8) | 0.0507 (8) | 0.0617 (9) | −0.0008 (6) | 0.0189 (7) | −0.0122 (7) |
C28 | 0.0683 (14) | 0.066 (2) | 0.074 (2) | 0.0077 (12) | 0.0148 (13) | −0.0267 (13) |
C1—C7 | 1.476 (3) | C12—O13 | 1.210 (3) |
C1—C2 | 1.504 (3) | C12—C14 | 1.505 (3) |
C1—C5 | 1.520 (3) | C14—C15 | 1.519 (4) |
C1—C6 | 1.533 (3) | C14—C16 | 1.525 (4) |
C2—C3 | 1.323 (3) | C14—C17 | 1.533 (5) |
C2—C10 | 1.488 (3) | O18—C19 | 1.353 (3) |
C3—C4 | 1.499 (3) | C19—O20 | 1.206 (3) |
C4—O18 | 1.450 (2) | C19—C21 | 1.516 (3) |
C4—C5 | 1.507 (3) | C21—C24 | 1.505 (4) |
C5—C6 | 1.486 (3) | C21—C22 | 1.526 (4) |
C6—C25 | 1.505 (3) | C21—C23 | 1.526 (4) |
C7—O9 | 1.192 (3) | C25—O26 | 1.190 (2) |
C7—O8 | 1.323 (3) | C25—O27 | 1.325 (2) |
C10—O11 | 1.445 (2) | O27—C28 | 1.449 (3) |
O11—C12 | 1.326 (3) | ||
C7—C1—C2 | 119.5 (2) | O13—C12—O11 | 121.5 (2) |
C7—C1—C5 | 125.6 (2) | O13—C12—C14 | 125.8 (2) |
C2—C1—C5 | 104.36 (15) | O11—C12—C14 | 112.6 (2) |
C7—C1—C6 | 121.8 (2) | C12—C14—C15 | 109.8 (2) |
C2—C1—C6 | 112.19 (14) | C12—C14—C16 | 111.4 (2) |
C5—C1—C6 | 58.23 (12) | C15—C14—C16 | 109.4 (2) |
C3—C2—C10 | 127.3 (2) | C12—C14—C17 | 106.1 (2) |
C3—C2—C1 | 110.9 (2) | C15—C14—C17 | 110.7 (3) |
C10—C2—C1 | 121.5 (2) | C16—C14—C17 | 109.4 (3) |
C2—C3—C4 | 113.0 (2) | C19—O18—C4 | 115.5 (2) |
O18—C4—C3 | 109.6 (2) | O20—C19—O18 | 121.4 (2) |
O18—C4—C5 | 112.1 (2) | O20—C19—C21 | 125.5 (2) |
C3—C4—C5 | 103.8 (2) | O18—C19—C21 | 113.1 (2) |
C6—C5—C4 | 117.7 (2) | C24—C21—C19 | 110.1 (2) |
C6—C5—C1 | 61.32 (12) | C24—C21—C22 | 110.9 (3) |
C4—C5—C1 | 107.7 (2) | C19—C21—C22 | 108.2 (2) |
C5—C6—C25 | 118.9 (2) | C24—C21—C23 | 109.3 (3) |
C5—C6—C1 | 60.45 (12) | C19—C21—C23 | 108.5 (2) |
C25—C6—C1 | 121.2 (2) | C22—C21—C23 | 109.8 (2) |
O9—C7—O8 | 122.9 (2) | O26—C25—O27 | 124.5 (2) |
O9—C7—C1 | 123.8 (2) | O26—C25—C6 | 125.4 (2) |
O8—C7—C1 | 113.3 (2) | O27—C25—C6 | 110.1 (2) |
O11—C10—C2 | 104.7 (2) | C25—O27—C28 | 115.7 (2) |
C12—O11—C10 | 118.9 (2) | ||
C7—C1—C2—C3 | 143.5 (2) | C6—C1—C7—O9 | −148.5 (2) |
C5—C1—C2—C3 | −3.2 (2) | C2—C1—C7—O8 | −179.2 (2) |
C6—C1—C2—C3 | −64.3 (2) | C5—C1—C7—O8 | −40.1 (3) |
C7—C1—C2—C10 | −42.6 (3) | C6—C1—C7—O8 | 31.4 (3) |
C5—C1—C2—C10 | 170.8 (2) | C3—C2—C10—O11 | 124.1 (2) |
C6—C1—C2—C10 | 109.6 (2) | C1—C2—C10—O11 | −48.8 (2) |
C10—C2—C3—C4 | −173.4 (2) | C2—C10—O11—C12 | 161.4 (2) |
C1—C2—C3—C4 | 0.1 (2) | C10—O11—C12—O13 | 5.7 (3) |
C2—C3—C4—O18 | −117.0 (2) | C10—O11—C12—C14 | −171.7 (2) |
C2—C3—C4—C5 | 3.0 (2) | O13—C12—C14—C15 | 26.1 (4) |
O18—C4—C5—C6 | 179.7 (2) | O11—C12—C14—C15 | −156.6 (2) |
C3—C4—C5—C6 | 61.5 (2) | O13—C12—C14—C16 | 147.5 (3) |
O18—C4—C5—C1 | 113.4 (2) | O11—C12—C14—C16 | −35.2 (3) |
C3—C4—C5—C1 | −4.8 (2) | O13—C12—C14—C17 | −93.5 (3) |
C7—C1—C5—C6 | 108.6 (2) | O11—C12—C14—C17 | 83.8 (3) |
C2—C1—C5—C6 | −107.5 (2) | C3—C4—O18—C19 | −164.3 (2) |
C6—C1—C5—C6 | 0.0 | C5—C4—O18—C19 | 80.9 (2) |
C7—C1—C5—C4 | −139.0 (2) | C4—O18—C19—O20 | −0.6 (3) |
C2—C1—C5—C4 | 4.9 (2) | C4—O18—C19—C21 | 179.1 (2) |
C6—C1—C5—C4 | 112.4 (2) | O20—C19—C21—C24 | −122.4 (3) |
C4—C5—C6—C25 | 152.4 (2) | O18—C19—C21—C24 | 57.9 (3) |
C1—C5—C6—C25 | −111.5 (2) | O20—C19—C21—C22 | −1.1 (4) |
C4—C5—C6—C1 | −96.0 (2) | O18—C19—C21—C22 | 179.3 (2) |
C1—C5—C6—C1 | 0.0 | O20—C19—C21—C23 | 118.0 (3) |
C7—C1—C6—C5 | −115.0 (2) | O18—C19—C21—C23 | −61.7 (3) |
C2—C1—C6—C5 | 93.6 (2) | C5—C6—C25—O26 | −27.3 (3) |
C5—C1—C6—C5 | 0.0 | C1—C6—C25—O26 | −98.4 (2) |
C7—C1—C6—C25 | −7.1 (3) | C5—C6—C25—O27 | 154.9 (2) |
C2—C1—C6—C25 | −158.5 (2) | C1—C6—C25—O27 | 83.8 (2) |
C5—C1—C6—C25 | 107.9 (2) | O26—C25—O27—C28 | 5.4 (3) |
C2—C1—C7—O9 | 0.9 (3) | C6—C25—O27—C28 | −176.7 (2) |
C5—C1—C7—O9 | 140.0 (2) |
Experimental details
Crystal data | |
Chemical formula | C20H28O8 |
Mr | 396.42 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 293 |
a, b, c (Å) | 8.869 (2), 9.836 (2), 12.225 (6) |
β (°) | 91.40 (3) |
V (Å3) | 1066.1 (6) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 0.80 |
Crystal size (mm) | 0.50 × 0.30 × 0.30 |
Data collection | |
Diffractometer | Nonius CAD4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4755, 3601, 3430 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.597 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.108, 1.06 |
No. of reflections | 3601 |
No. of parameters | 255 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.20 |
Computer programs: CAD-4 Software (Enraf-Nonius, 1987), CAD-4 Software, NONIUS (Riche, 1989), SHELXS86 (Sheldrick, 1985), SHELXL93 (Sheldrick, 1993), R3M (Riche, 1983) and ORTEP (Johnson, 1963).
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
Polyhydroxylated aminocyclopentanes, exemplified by mannostatins A and B, isolated from the culture broth of Streptoverticillium verticillus, exhibit potent inhibiting activity towards α-mannosidase (Aoyagi et al., 1989; Aoyagi et al., 1990). Consequently, they display interesting biological activities, such as antiviral, antimetastasic and immunomodulator (Jacob et al., 1995 and references cited therein; Breton et al., 1991). To contribute to the investigation of structure-activity relationships, we prepared the conformationally restricted bicyclo[3.1.0]hexane analogue, (I) (Cachet et al. unpublished). A novel synthetic approach was developped, starting from the natural iridoid aucubin (II) as source of chiral cyclopentane. The key step was the reaction of iodolactones derived from (II) with sodium triethylsilanolate (TMSONa) to create the cyclopropane ring. In the course of the synthesis, compound (III) was obtained. The stereochemistry at C1, C5, C6 and consequently, the mechanism of the TMSONa rearrangement were confirmed by this X-ray diffraction analysis. \sch
The carboxylic acid at C1 eclipses unexpectedly the C1—C2 bond (torsional angle: C2—C1—C7—O9 = 0.9 (3)°). This is probably to be ascribed to the hydrogen bond which links the carboxylic acid O8—H to the O13 carbonyl of symmetry-related molecule (-x, -1/2 + y, 1 - z). (O8···O13 = 2.702 (2), H···O13 1.93 Å, angle O8—H···O13 156.5°). The cyclopentene ring is practically planar: C4 being at 0.067 Å of the mean plane of the four other atoms. The cyclopropane ring makes a dihedral angle of 109.4° with the mean plane of the cyclopentene ring.