The title compounds, (2R,2''S,3b'S,4a'R,7b'S,8a'R)-perhydrodispiro[furan-2,3'-dicyclopenta[a,e]pentalene-7',2''-furan]-5,5''-dione, C20H26O4, and (3aR,3bR,4aR,4bS,5aS,8aR,8bR,9aR,9bS,10aS)-perhydrodipentaleno[2,1-a:2',1'-e]pentalene-1,6-dione, C20H26O2, are intermediates identified during the synthesis of dodecahedrane. Crystallographic studies have established the ring-junction stereochemistry for these important intermediates. All the ring junctions are cis-fused, and the molecular packing is stabilized by van der Waals interactions.
Supporting information
CCDC references: 162351; 163062
X-ray analysis of intermediate (I) (Scheme 1), established the required all-cis-syn stereochemistry at the ring junctions. The key tetracyclic dione, 2, obtained from 1 was converted to diol 3 by the Grignard addition reaction. Then diol 3 was converted to bis-lactone (I) via the hydroboration reaction followed by the Jones oxidation sequence. Similarly, hexacyclic ketone (II) was prepared from bicyclic dione 5 via the intermediate 6 (Scheme 2). The proton-decoupled 13C NMR spectrum of (II) showed ten lines, as expected, which could be attributed to the presence of C2-symmetry in the molecule. However, the spectral data did not allow us to assign the relative stereochemistry at the ring junctions. Crystallization of (II) afforded a single-crystal suitable for X-ray analysis. The fusion at the ring junctions was unequivocally ascertained by X-ray diffraction studies.
H atoms were fixed geometrically at calculated position.
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1995) for (I); CAD-4 EXPRESS for (II). For both compounds, cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997). Molecular graphics: ORTEP-3 (Johnson & Burnett, 1996; Farrugia, 1999) for (I); ORTEP-3(Johnson & Burnett, 1996; Farrugia, 1999) for (II).
(I) (2
R,2''
S,3'bS,4'aR,7'bS,8'aR)-perhydrodispiro[furan-2,3'- dicyclopenta[a,e]pentalene-7',2''-furan]-5,5''-dione
top
Crystal data top
C20H26O4 | F(000) = 712 |
Mr = 330.41 | Dx = 1.312 Mg m−3 |
Monoclinic, P21/c | Cu Kα radiation, λ = 1.5418 Å |
a = 7.085 (3) Å | Cell parameters from 25 reflections |
b = 12.064 (5) Å | θ = 8.6–25.6° |
c = 19.583 (5) Å | µ = 0.73 mm−1 |
β = 91.54 (3)° | T = 293 K |
V = 1673.2 (11) Å3 | Rectangular needle, colourless |
Z = 4 | 0.2 × 0.05 × 0.01 mm |
Data collection top
Enraf Nonius CAD4 diffractometer | Rint = 0.035 |
Radiation source: fine-focus sealed tube | θmax = 68.0°, θmin = 4.3° |
Graphite monochromator | h = 0→8 |
non–profiled ω/2θ scans | k = 0→14 |
3346 measured reflections | l = −23→23 |
3054 independent reflections | 3 standard reflections every 200 reflections |
1727 reflections with I > 2σ(I) | intensity decay: none |
Refinement top
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)] = 0.051 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.143 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0676P)2 + 0.0257P] where P = (Fo2 + 2Fc2)/3 |
3054 reflections | (Δ/σ)max = 0.005 |
217 parameters | Δρmax = 0.19 e Å−3 |
0 restraints | Δρmin = −0.26 e Å−3 |
Crystal data top
C20H26O4 | V = 1673.2 (11) Å3 |
Mr = 330.41 | Z = 4 |
Monoclinic, P21/c | Cu Kα radiation |
a = 7.085 (3) Å | µ = 0.73 mm−1 |
b = 12.064 (5) Å | T = 293 K |
c = 19.583 (5) Å | 0.2 × 0.05 × 0.01 mm |
β = 91.54 (3)° | |
Data collection top
Enraf Nonius CAD4 diffractometer | Rint = 0.035 |
3346 measured reflections | 3 standard reflections every 200 reflections |
3054 independent reflections | intensity decay: none |
1727 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.051 | 0 restraints |
wR(F2) = 0.143 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.19 e Å−3 |
3054 reflections | Δρmin = −0.26 e Å−3 |
217 parameters | |
Special details top
Experimental. Data beyond theta grater than 60° was weak and not included |
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 | x | y | z | Uiso*/Ueq | |
O1 | −0.2004 (3) | 0.24033 (19) | 0.20409 (12) | 0.0728 (7) | |
C1 | −0.0355 (4) | 0.2188 (2) | 0.20106 (14) | 0.0488 (7) | |
C2 | 0.2323 (3) | 0.1092 (2) | 0.20137 (13) | 0.0405 (6) | |
O2 | 0.0273 (2) | 0.11409 (15) | 0.20733 (9) | 0.0478 (5) | |
C3 | 0.2948 (4) | 0.2295 (2) | 0.21526 (15) | 0.0462 (7) | |
H3A | 0.3240 | 0.2410 | 0.2634 | 0.055* | |
H3B | 0.4046 | 0.2484 | 0.1891 | 0.055* | |
C4 | 0.1260 (4) | 0.2962 (2) | 0.19243 (15) | 0.0496 (7) | |
H4A | 0.1124 | 0.3618 | 0.2206 | 0.059* | |
H4B | 0.1357 | 0.3187 | 0.1451 | 0.059* | |
C5 | 0.2923 (3) | 0.0675 (2) | 0.13113 (13) | 0.0419 (6) | |
H5 | 0.3161 | 0.1317 | 0.1019 | 0.050* | |
C6 | 0.4822 (4) | 0.0068 (2) | 0.14596 (15) | 0.0493 (7) | |
H6 | 0.5852 | 0.0466 | 0.1243 | 0.059* | |
C7 | 0.5126 (4) | 0.0079 (2) | 0.22367 (15) | 0.0600 (8) | |
H7A | 0.5638 | −0.0624 | 0.2396 | 0.072* | |
H7B | 0.5989 | 0.0667 | 0.2375 | 0.072* | |
C8 | 0.3177 (4) | 0.0277 (2) | 0.25244 (14) | 0.0515 (7) | |
H8A | 0.2450 | −0.0404 | 0.2538 | 0.062* | |
H8B | 0.3265 | 0.0594 | 0.2979 | 0.062* | |
C9 | 0.1680 (3) | −0.0155 (2) | 0.09083 (13) | 0.0442 (7) | |
H9 | 0.0953 | 0.0241 | 0.0552 | 0.053* | |
C10 | 0.3085 (4) | −0.0943 (2) | 0.05733 (13) | 0.0460 (7) | |
H10 | 0.3642 | −0.0571 | 0.0182 | 0.055* | |
C11 | 0.4588 (4) | −0.1083 (2) | 0.11381 (17) | 0.0579 (8) | |
H11A | 0.5768 | −0.1335 | 0.0951 | 0.069* | |
H11B | 0.4183 | −0.1617 | 0.1475 | 0.069* | |
C12 | 0.0392 (3) | −0.0969 (2) | 0.12675 (14) | 0.0500 (7) | |
H12A | −0.0801 | −0.0622 | 0.1372 | 0.060* | |
H12B | 0.0984 | −0.1236 | 0.1689 | 0.060* | |
C13 | 0.0089 (4) | −0.1925 (2) | 0.07562 (14) | 0.0464 (7) | |
H13 | −0.1030 | −0.1779 | 0.0465 | 0.056* | |
C14 | 0.1889 (3) | −0.1929 (2) | 0.03174 (13) | 0.0407 (6) | |
H14 | 0.1512 | −0.1799 | −0.0161 | 0.049* | |
C15 | −0.0047 (4) | −0.3076 (2) | 0.10727 (16) | 0.0599 (8) | |
H15A | −0.0504 | −0.3031 | 0.1534 | 0.072* | |
H15B | −0.0893 | −0.3545 | 0.0803 | 0.072* | |
C16 | 0.1958 (4) | −0.3528 (2) | 0.10732 (14) | 0.0566 (8) | |
H16A | 0.2718 | −0.3226 | 0.1449 | 0.068* | |
H16B | 0.1971 | −0.4331 | 0.1100 | 0.068* | |
C17 | 0.2644 (3) | −0.3126 (2) | 0.03896 (13) | 0.0443 (7) | |
O17 | 0.4702 (2) | −0.31673 (16) | 0.03668 (10) | 0.0527 (5) | |
C18 | 0.2010 (4) | −0.3864 (2) | −0.02122 (14) | 0.0536 (7) | |
H18A | 0.1805 | −0.4621 | −0.0063 | 0.064* | |
H18B | 0.0856 | −0.3586 | −0.0427 | 0.064* | |
C19 | 0.3625 (4) | −0.3801 (3) | −0.06916 (16) | 0.0665 (9) | |
H19A | 0.3836 | −0.4512 | −0.0907 | 0.080* | |
H19B | 0.3382 | −0.3249 | −0.1044 | 0.080* | |
C20 | 0.5273 (4) | −0.3479 (2) | −0.02507 (15) | 0.0527 (7) | |
O20 | 0.6920 (3) | −0.3480 (2) | −0.03866 (11) | 0.0730 (7) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0437 (12) | 0.0678 (15) | 0.1068 (19) | 0.0111 (11) | 0.0004 (11) | 0.0000 (13) |
C1 | 0.0408 (16) | 0.0489 (17) | 0.0565 (17) | 0.0064 (13) | −0.0042 (13) | −0.0015 (13) |
C2 | 0.0325 (13) | 0.0391 (14) | 0.0500 (15) | −0.0008 (11) | 0.0021 (11) | −0.0006 (12) |
O2 | 0.0374 (10) | 0.0441 (11) | 0.0622 (12) | −0.0024 (8) | 0.0056 (8) | −0.0051 (9) |
C3 | 0.0427 (15) | 0.0399 (15) | 0.0561 (17) | −0.0015 (12) | 0.0017 (12) | −0.0054 (13) |
C4 | 0.0509 (17) | 0.0364 (15) | 0.0616 (18) | 0.0019 (13) | 0.0034 (14) | 0.0000 (13) |
C5 | 0.0453 (15) | 0.0343 (13) | 0.0462 (15) | −0.0002 (12) | 0.0050 (12) | 0.0044 (12) |
C6 | 0.0354 (14) | 0.0425 (16) | 0.0702 (19) | −0.0043 (12) | 0.0054 (13) | −0.0103 (14) |
C7 | 0.0506 (17) | 0.0489 (18) | 0.080 (2) | 0.0092 (14) | −0.0148 (16) | −0.0092 (16) |
C8 | 0.0608 (18) | 0.0437 (16) | 0.0494 (16) | −0.0029 (14) | −0.0087 (14) | 0.0028 (13) |
C9 | 0.0450 (15) | 0.0405 (14) | 0.0468 (15) | 0.0070 (12) | −0.0047 (12) | 0.0021 (12) |
C10 | 0.0462 (15) | 0.0456 (16) | 0.0469 (15) | −0.0043 (13) | 0.0133 (12) | −0.0007 (12) |
C11 | 0.0293 (14) | 0.0531 (18) | 0.091 (2) | 0.0031 (13) | −0.0004 (14) | −0.0208 (17) |
C12 | 0.0320 (14) | 0.0576 (18) | 0.0609 (18) | −0.0016 (13) | 0.0081 (12) | −0.0139 (14) |
C13 | 0.0364 (15) | 0.0520 (16) | 0.0506 (16) | −0.0026 (12) | −0.0023 (12) | −0.0081 (13) |
C14 | 0.0412 (15) | 0.0432 (15) | 0.0375 (14) | 0.0031 (12) | −0.0007 (11) | 0.0025 (12) |
C15 | 0.063 (2) | 0.0607 (19) | 0.0568 (18) | −0.0168 (16) | 0.0125 (15) | −0.0052 (15) |
C16 | 0.075 (2) | 0.0422 (16) | 0.0525 (18) | −0.0051 (15) | −0.0027 (15) | 0.0036 (13) |
C17 | 0.0376 (15) | 0.0446 (15) | 0.0506 (16) | −0.0020 (12) | −0.0014 (12) | −0.0033 (13) |
O17 | 0.0419 (11) | 0.0549 (12) | 0.0610 (12) | 0.0076 (9) | −0.0047 (9) | −0.0124 (10) |
C18 | 0.0569 (18) | 0.0457 (16) | 0.0578 (18) | −0.0030 (14) | −0.0057 (14) | −0.0107 (14) |
C19 | 0.063 (2) | 0.084 (2) | 0.0526 (18) | 0.0077 (18) | −0.0038 (15) | −0.0099 (17) |
C20 | 0.0525 (18) | 0.0504 (17) | 0.0555 (18) | 0.0083 (14) | 0.0045 (15) | −0.0014 (14) |
O20 | 0.0526 (13) | 0.0873 (17) | 0.0798 (16) | 0.0118 (12) | 0.0114 (11) | −0.0001 (12) |
Geometric parameters (Å, º) top
O1—C1 | 1.200 (3) | C10—H10 | 0.9800 |
C1—O2 | 1.344 (3) | C11—H11A | 0.9700 |
C1—C4 | 1.490 (4) | C11—H11B | 0.9700 |
C2—O2 | 1.462 (3) | C12—C13 | 1.538 (4) |
C2—C8 | 1.517 (4) | C12—H12A | 0.9700 |
C2—C5 | 1.535 (3) | C12—H12B | 0.9700 |
C2—C3 | 1.539 (3) | C13—C15 | 1.525 (4) |
C3—C4 | 1.501 (4) | C13—C14 | 1.557 (3) |
C3—H3A | 0.9700 | C13—H13 | 0.9800 |
C3—H3B | 0.9700 | C14—C17 | 1.545 (4) |
C4—H4A | 0.9700 | C14—H14 | 0.9800 |
C4—H4B | 0.9700 | C15—C16 | 1.522 (4) |
C5—C9 | 1.537 (3) | C15—H15A | 0.9700 |
C5—C6 | 1.552 (3) | C15—H15B | 0.9700 |
C5—H5 | 0.9800 | C16—C17 | 1.516 (4) |
C6—C7 | 1.531 (4) | C16—H16A | 0.9700 |
C6—C11 | 1.533 (4) | C16—H16B | 0.9700 |
C6—H6 | 0.9800 | C17—O17 | 1.461 (3) |
C7—C8 | 1.524 (4) | C17—C18 | 1.535 (4) |
C7—H7A | 0.9700 | O17—C20 | 1.340 (3) |
C7—H7B | 0.9700 | C18—C19 | 1.501 (4) |
C8—H8A | 0.9700 | C18—H18A | 0.9700 |
C8—H8B | 0.9700 | C18—H18B | 0.9700 |
C9—C12 | 1.526 (4) | C19—C20 | 1.485 (4) |
C9—C10 | 1.536 (3) | C19—H19A | 0.9700 |
C9—H9 | 0.9800 | C19—H19B | 0.9700 |
C10—C11 | 1.524 (4) | C20—O20 | 1.203 (3) |
C10—C14 | 1.537 (4) | | |
| | | |
O1—C1—O2 | 121.3 (3) | C10—C11—C6 | 105.2 (2) |
O1—C1—C4 | 128.5 (3) | C10—C11—H11A | 110.7 |
O2—C1—C4 | 110.3 (2) | C6—C11—H11A | 110.7 |
O2—C2—C8 | 110.7 (2) | C10—C11—H11B | 110.7 |
O2—C2—C5 | 112.6 (2) | C6—C11—H11B | 110.7 |
C8—C2—C5 | 105.3 (2) | H11A—C11—H11B | 108.8 |
O2—C2—C3 | 103.27 (19) | C9—C12—C13 | 104.9 (2) |
C8—C2—C3 | 112.8 (2) | C9—C12—H12A | 110.8 |
C5—C2—C3 | 112.4 (2) | C13—C12—H12A | 110.8 |
C1—O2—C2 | 111.0 (2) | C9—C12—H12B | 110.8 |
C4—C3—C2 | 103.3 (2) | C13—C12—H12B | 110.8 |
C4—C3—H3A | 111.1 | H12A—C12—H12B | 108.8 |
C2—C3—H3A | 111.1 | C15—C13—C12 | 115.3 (2) |
C4—C3—H3B | 111.1 | C15—C13—C14 | 106.4 (2) |
C2—C3—H3B | 111.1 | C12—C13—C14 | 105.1 (2) |
H3A—C3—H3B | 109.1 | C15—C13—H13 | 109.9 |
C1—C4—C3 | 103.8 (2) | C12—C13—H13 | 109.9 |
C1—C4—H4A | 111.0 | C14—C13—H13 | 109.9 |
C3—C4—H4A | 111.0 | C10—C14—C17 | 120.5 (2) |
C1—C4—H4B | 111.0 | C10—C14—C13 | 105.7 (2) |
C3—C4—H4B | 111.0 | C17—C14—C13 | 103.9 (2) |
H4A—C4—H4B | 109.0 | C10—C14—H14 | 108.8 |
C2—C5—C9 | 120.3 (2) | C17—C14—H14 | 108.8 |
C2—C5—C6 | 104.2 (2) | C13—C14—H14 | 108.8 |
C9—C5—C6 | 105.7 (2) | C16—C15—C13 | 104.9 (2) |
C2—C5—H5 | 108.7 | C16—C15—H15A | 110.8 |
C9—C5—H5 | 108.7 | C13—C15—H15A | 110.8 |
C6—C5—H5 | 108.7 | C16—C15—H15B | 110.8 |
C7—C6—C11 | 115.2 (2) | C13—C15—H15B | 110.8 |
C7—C6—C5 | 106.3 (2) | H15A—C15—H15B | 108.8 |
C11—C6—C5 | 105.5 (2) | C17—C16—C15 | 101.9 (2) |
C7—C6—H6 | 109.9 | C17—C16—H16A | 111.4 |
C11—C6—H6 | 109.9 | C15—C16—H16A | 111.4 |
C5—C6—H6 | 109.9 | C17—C16—H16B | 111.4 |
C8—C7—C6 | 105.3 (2) | C15—C16—H16B | 111.4 |
C8—C7—H7A | 110.7 | H16A—C16—H16B | 109.3 |
C6—C7—H7A | 110.7 | O17—C17—C16 | 111.1 (2) |
C8—C7—H7B | 110.7 | O17—C17—C18 | 103.2 (2) |
C6—C7—H7B | 110.7 | C16—C17—C18 | 113.4 (2) |
H7A—C7—H7B | 108.8 | O17—C17—C14 | 111.9 (2) |
C2—C8—C7 | 102.0 (2) | C16—C17—C14 | 105.1 (2) |
C2—C8—H8A | 111.4 | C18—C17—C14 | 112.2 (2) |
C7—C8—H8A | 111.4 | C20—O17—C17 | 111.3 (2) |
C2—C8—H8B | 111.4 | C19—C18—C17 | 103.8 (2) |
C7—C8—H8B | 111.4 | C19—C18—H18A | 111.0 |
H8A—C8—H8B | 109.2 | C17—C18—H18A | 111.0 |
C12—C9—C10 | 101.6 (2) | C19—C18—H18B | 111.0 |
C12—C9—C5 | 121.6 (2) | C17—C18—H18B | 111.0 |
C10—C9—C5 | 104.7 (2) | H18A—C18—H18B | 109.0 |
C12—C9—H9 | 109.4 | C20—C19—C18 | 104.5 (2) |
C10—C9—H9 | 109.4 | C20—C19—H19A | 110.9 |
C5—C9—H9 | 109.4 | C18—C19—H19A | 110.9 |
C11—C10—C9 | 102.0 (2) | C20—C19—H19B | 110.9 |
C11—C10—C14 | 121.2 (2) | C18—C19—H19B | 110.9 |
C9—C10—C14 | 105.1 (2) | H19A—C19—H19B | 108.9 |
C11—C10—H10 | 109.3 | O20—C20—O17 | 121.2 (3) |
C9—C10—H10 | 109.3 | O20—C20—C19 | 128.5 (3) |
C14—C10—H10 | 109.3 | O17—C20—C19 | 110.2 (2) |
| | | |
O1—C1—O2—C2 | 179.6 (3) | C7—C6—C11—C10 | 141.7 (2) |
C4—C1—O2—C2 | −1.9 (3) | C5—C6—C11—C10 | 24.8 (3) |
C8—C2—O2—C1 | 139.9 (2) | C10—C9—C12—C13 | −41.1 (3) |
C5—C2—O2—C1 | −102.5 (2) | C5—C9—C12—C13 | −156.6 (2) |
C3—C2—O2—C1 | 19.0 (3) | C9—C12—C13—C15 | 144.2 (2) |
O2—C2—C3—C4 | −27.9 (3) | C9—C12—C13—C14 | 27.4 (3) |
C8—C2—C3—C4 | −147.4 (2) | C11—C10—C14—C17 | −25.1 (4) |
C5—C2—C3—C4 | 93.7 (2) | C9—C10—C14—C17 | −139.6 (2) |
O1—C1—C4—C3 | 161.9 (3) | C11—C10—C14—C13 | 91.9 (3) |
O2—C1—C4—C3 | −16.5 (3) | C9—C10—C14—C13 | −22.6 (3) |
C2—C3—C4—C1 | 26.8 (3) | C15—C13—C14—C10 | −125.5 (2) |
O2—C2—C5—C9 | −31.0 (3) | C12—C13—C14—C10 | −2.8 (3) |
C8—C2—C5—C9 | 89.7 (3) | C15—C13—C14—C17 | 2.2 (3) |
C3—C2—C5—C9 | −147.1 (2) | C12—C13—C14—C17 | 124.9 (2) |
O2—C2—C5—C6 | −149.1 (2) | C12—C13—C15—C16 | −92.9 (3) |
C8—C2—C5—C6 | −28.4 (2) | C14—C13—C15—C16 | 23.1 (3) |
C3—C2—C5—C6 | 94.7 (2) | C13—C15—C16—C17 | −39.6 (3) |
C2—C5—C6—C7 | 4.8 (3) | C15—C16—C17—O17 | 162.5 (2) |
C9—C5—C6—C7 | −123.0 (2) | C15—C16—C17—C18 | −81.8 (3) |
C2—C5—C6—C11 | 127.6 (2) | C15—C16—C17—C14 | 41.3 (3) |
C9—C5—C6—C11 | −0.2 (3) | C10—C14—C17—O17 | −29.7 (3) |
C11—C6—C7—C8 | −96.1 (3) | C13—C14—C17—O17 | −147.6 (2) |
C5—C6—C7—C8 | 20.4 (3) | C10—C14—C17—C16 | 91.0 (3) |
O2—C2—C8—C7 | 162.9 (2) | C13—C14—C17—C16 | −26.9 (2) |
C5—C2—C8—C7 | 41.0 (3) | C10—C14—C17—C18 | −145.2 (2) |
C3—C2—C8—C7 | −81.9 (3) | C13—C14—C17—C18 | 96.9 (2) |
C6—C7—C8—C2 | −37.6 (3) | C16—C17—O17—C20 | 142.3 (2) |
C2—C5—C9—C12 | −27.8 (3) | C18—C17—O17—C20 | 20.4 (3) |
C6—C5—C9—C12 | 89.6 (3) | C14—C17—O17—C20 | −100.5 (2) |
C2—C5—C9—C10 | −141.7 (2) | O17—C17—C18—C19 | −26.0 (3) |
C6—C5—C9—C10 | −24.3 (3) | C16—C17—C18—C19 | −146.3 (2) |
C12—C9—C10—C11 | −88.0 (2) | C14—C17—C18—C19 | 94.7 (3) |
C5—C9—C10—C11 | 39.3 (3) | C17—C18—C19—C20 | 22.8 (3) |
C12—C9—C10—C14 | 39.3 (3) | C17—O17—C20—O20 | 174.2 (3) |
C5—C9—C10—C14 | 166.7 (2) | C17—O17—C20—C19 | −6.1 (3) |
C9—C10—C11—C6 | −39.6 (3) | C18—C19—C20—O20 | 168.4 (3) |
C14—C10—C11—C6 | −155.8 (2) | C18—C19—C20—O17 | −11.3 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4B···O20i | 0.97 | 2.47 | 3.366 (4) | 154 |
C19—H19B···O1ii | 0.97 | 2.39 | 3.314 (4) | 159 |
Symmetry codes: (i) −x+1, −y, −z; (ii) −x, −y, −z. |
(II) (3aR,3bR,4aR,4bS,5aS,8aR,8bR,9aR,9bS,10aS)- perhydrodipentaleno[2,1 − a:2',1'-e]pentalene-1,6-dione
top
Crystal data top
C20H26O2 | F(000) = 648 |
Mr = 298.41 | Dx = 1.280 Mg m−3 |
Monoclinic, I2/a | Cu Kα radiation, λ = 1.5418 Å |
a = 9.415 (8) Å | Cell parameters from 25 reflections |
b = 10.739 (2) Å | θ = 22.1–28.6° |
c = 15.332 (3) Å | µ = 0.63 mm−1 |
β = 92.58 (4)° | T = 293 K |
V = 1548.6 (14) Å3 | Rectangle, colourless |
Z = 4 | 0.33 × 0.2 × 0.1 mm |
Data collection top
Enraf Nonius CAD4 diffractometer | Rint = 0.036 |
Radiation source: fine-focus sealed tube | θmax = 71.9°, θmin = 5.0° |
Graphite monochromator | h = −1→11 |
non–profiled ω/2θ scans | k = 0→13 |
1724 measured reflections | l = −18→18 |
1505 independent reflections | 3 standard reflections every 200 reflections |
1244 reflections with I > 2σ(I) | intensity decay: none |
Refinement top
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)] = 0.040 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0437P)2 + 1.1616P] where P = (Fo2 + 2Fc2)/3 |
1505 reflections | (Δ/σ)max < 0.001 |
100 parameters | Δρmax = 0.20 e Å−3 |
0 restraints | Δρmin = −0.17 e Å−3 |
Crystal data top
C20H26O2 | V = 1548.6 (14) Å3 |
Mr = 298.41 | Z = 4 |
Monoclinic, I2/a | Cu Kα radiation |
a = 9.415 (8) Å | µ = 0.63 mm−1 |
b = 10.739 (2) Å | T = 293 K |
c = 15.332 (3) Å | 0.33 × 0.2 × 0.1 mm |
β = 92.58 (4)° | |
Data collection top
Enraf Nonius CAD4 diffractometer | Rint = 0.036 |
1724 measured reflections | 3 standard reflections every 200 reflections |
1505 independent reflections | intensity decay: none |
1244 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.20 e Å−3 |
1505 reflections | Δρmin = −0.17 e Å−3 |
100 parameters | |
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 | x | y | z | Uiso*/Ueq | |
C1 | 0.27172 (16) | 0.87046 (14) | 0.59610 (10) | 0.0363 (4) | |
H1A | 0.2307 | 0.9500 | 0.5787 | 0.044* | |
H1B | 0.2557 | 0.8571 | 0.6575 | 0.044* | |
C2 | 0.20445 (15) | 0.76450 (13) | 0.54048 (8) | 0.0316 (3) | |
H2 | 0.2114 | 0.6847 | 0.5714 | 0.038* | |
C3 | 0.05300 (15) | 0.78815 (13) | 0.50439 (9) | 0.0323 (3) | |
H3 | −0.0013 | 0.8337 | 0.5471 | 0.039* | |
C4 | −0.02773 (16) | 0.67118 (14) | 0.47388 (10) | 0.0370 (4) | |
H4A | −0.0814 | 0.6365 | 0.5206 | 0.044* | |
H4B | 0.0371 | 0.6083 | 0.4536 | 0.044* | |
C5 | −0.12755 (16) | 0.71772 (14) | 0.39862 (10) | 0.0365 (4) | |
H5 | −0.2110 | 0.7602 | 0.4203 | 0.044* | |
C6 | −0.03230 (15) | 0.80764 (14) | 0.34959 (9) | 0.0343 (3) | |
H6 | −0.0907 | 0.8718 | 0.3199 | 0.041* | |
C7 | 0.06809 (16) | 0.86823 (13) | 0.42006 (9) | 0.0334 (3) | |
H7 | 0.0357 | 0.9533 | 0.4312 | 0.040* | |
C8 | −0.16925 (19) | 0.61669 (16) | 0.33417 (11) | 0.0475 (4) | |
O8 | −0.26489 (17) | 0.54259 (15) | 0.34168 (10) | 0.0782 (5) | |
C9 | −0.0749 (2) | 0.62503 (19) | 0.25785 (13) | 0.0573 (5) | |
H9A | −0.1298 | 0.6489 | 0.2054 | 0.069* | |
H9B | −0.0299 | 0.5454 | 0.2477 | 0.069* | |
C10 | 0.03653 (18) | 0.72361 (16) | 0.28153 (10) | 0.0445 (4) | |
H10A | 0.0598 | 0.7714 | 0.2304 | 0.053* | |
H10B | 0.1227 | 0.6854 | 0.3061 | 0.053* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0414 (8) | 0.0343 (8) | 0.0333 (7) | 0.0025 (6) | 0.0030 (6) | −0.0049 (6) |
C2 | 0.0368 (8) | 0.0291 (7) | 0.0290 (7) | 0.0000 (6) | 0.0045 (6) | 0.0017 (6) |
C3 | 0.0366 (8) | 0.0299 (7) | 0.0309 (7) | 0.0011 (6) | 0.0060 (6) | −0.0003 (6) |
C4 | 0.0387 (8) | 0.0324 (8) | 0.0400 (8) | −0.0021 (6) | 0.0030 (6) | 0.0047 (6) |
C5 | 0.0351 (8) | 0.0345 (8) | 0.0400 (8) | −0.0002 (6) | 0.0021 (6) | −0.0007 (6) |
C6 | 0.0377 (8) | 0.0307 (7) | 0.0345 (7) | 0.0049 (6) | 0.0010 (6) | 0.0024 (6) |
C7 | 0.0409 (8) | 0.0251 (7) | 0.0343 (7) | 0.0035 (6) | 0.0037 (6) | 0.0012 (6) |
C8 | 0.0516 (10) | 0.0387 (9) | 0.0511 (10) | −0.0028 (8) | −0.0112 (8) | −0.0016 (7) |
O8 | 0.0887 (11) | 0.0684 (10) | 0.0768 (10) | −0.0395 (9) | −0.0052 (8) | −0.0070 (8) |
C9 | 0.0584 (11) | 0.0575 (11) | 0.0554 (11) | 0.0040 (9) | −0.0035 (9) | −0.0217 (9) |
C10 | 0.0467 (9) | 0.0491 (9) | 0.0378 (8) | 0.0045 (8) | 0.0034 (7) | −0.0070 (7) |
Geometric parameters (Å, º) top
C1—C7i | 1.540 (2) | C5—C6 | 1.537 (2) |
C1—C2 | 1.541 (2) | C5—H5 | 0.9800 |
C1—H1A | 0.9700 | C6—C10 | 1.544 (2) |
C1—H1B | 0.9700 | C6—C7 | 1.547 (2) |
C2—C3 | 1.527 (2) | C6—H6 | 0.9800 |
C2—C2i | 1.540 (3) | C7—C1i | 1.540 (2) |
C2—H2 | 0.9800 | C7—H7 | 0.9800 |
C3—C4 | 1.531 (2) | C8—O8 | 1.211 (2) |
C3—C7 | 1.5647 (19) | C8—C9 | 1.503 (3) |
C3—H3 | 0.9800 | C9—C10 | 1.523 (3) |
C4—C5 | 1.538 (2) | C9—H9A | 0.9700 |
C4—H4A | 0.9700 | C9—H9B | 0.9700 |
C4—H4B | 0.9700 | C10—H10A | 0.9700 |
C5—C8 | 1.508 (2) | C10—H10B | 0.9700 |
| | | |
C7i—C1—C2 | 106.30 (12) | C4—C5—H5 | 111.6 |
C7i—C1—H1A | 110.5 | C5—C6—C10 | 103.60 (13) |
C2—C1—H1A | 110.5 | C5—C6—C7 | 105.93 (12) |
C7i—C1—H1B | 110.5 | C10—C6—C7 | 117.14 (13) |
C2—C1—H1B | 110.5 | C5—C6—H6 | 109.9 |
H1A—C1—H1B | 108.7 | C10—C6—H6 | 109.9 |
C3—C2—C2i | 104.64 (14) | C7—C6—H6 | 109.9 |
C3—C2—C1 | 115.56 (12) | C1i—C7—C6 | 117.80 (13) |
C2i—C2—C1 | 102.48 (11) | C1i—C7—C3 | 105.52 (12) |
C3—C2—H2 | 111.2 | C6—C7—C3 | 105.70 (11) |
C2i—C2—H2 | 111.2 | C1i—C7—H7 | 109.2 |
C1—C2—H2 | 111.2 | C6—C7—H7 | 109.2 |
C2—C3—C4 | 114.64 (12) | C3—C7—H7 | 109.2 |
C2—C3—C7 | 105.83 (12) | O8—C8—C9 | 125.52 (17) |
C4—C3—C7 | 105.12 (11) | O8—C8—C5 | 125.69 (17) |
C2—C3—H3 | 110.3 | C9—C8—C5 | 108.77 (14) |
C4—C3—H3 | 110.3 | C8—C9—C10 | 106.30 (14) |
C7—C3—H3 | 110.3 | C8—C9—H9A | 110.5 |
C3—C4—C5 | 103.94 (12) | C10—C9—H9A | 110.5 |
C3—C4—H4A | 111.0 | C8—C9—H9B | 110.5 |
C5—C4—H4A | 111.0 | C10—C9—H9B | 110.5 |
C3—C4—H4B | 111.0 | H9A—C9—H9B | 108.7 |
C5—C4—H4B | 111.0 | C9—C10—C6 | 105.17 (14) |
H4A—C4—H4B | 109.0 | C9—C10—H10A | 110.7 |
C8—C5—C6 | 105.79 (12) | C6—C10—H10A | 110.7 |
C8—C5—C4 | 112.96 (13) | C9—C10—H10B | 110.7 |
C6—C5—C4 | 102.75 (12) | C6—C10—H10B | 110.7 |
C8—C5—H5 | 111.6 | H10A—C10—H10B | 108.8 |
C6—C5—H5 | 111.6 | | |
| | | |
C7i—C1—C2—C3 | −147.29 (12) | C5—C6—C7—C3 | 13.43 (14) |
C7i—C1—C2—C2i | −34.16 (15) | C10—C6—C7—C3 | −101.46 (15) |
C2i—C2—C3—C4 | 85.77 (11) | C2—C3—C7—C1i | 8.23 (14) |
C1—C2—C3—C4 | −162.36 (12) | C4—C3—C7—C1i | −113.47 (13) |
C2i—C2—C3—C7 | −29.58 (10) | C2—C3—C7—C6 | 133.75 (12) |
C1—C2—C3—C7 | 82.28 (14) | C4—C3—C7—C6 | 12.05 (14) |
C2—C3—C4—C5 | −148.74 (12) | C6—C5—C8—O8 | −164.54 (18) |
C7—C3—C4—C5 | −32.97 (15) | C4—C5—C8—O8 | 83.8 (2) |
C3—C4—C5—C8 | 154.73 (13) | C6—C5—C8—C9 | 14.04 (18) |
C3—C4—C5—C6 | 41.22 (14) | C4—C5—C8—C9 | −97.61 (17) |
C8—C5—C6—C10 | −28.40 (15) | O8—C8—C9—C10 | −175.07 (18) |
C4—C5—C6—C10 | 90.26 (13) | C5—C8—C9—C10 | 6.35 (19) |
C8—C5—C6—C7 | −152.25 (12) | C8—C9—C10—C6 | −24.14 (18) |
C4—C5—C6—C7 | −33.59 (14) | C5—C6—C10—C9 | 32.34 (16) |
C5—C6—C7—C1i | 130.98 (13) | C7—C6—C10—C9 | 148.52 (14) |
C10—C6—C7—C1i | 16.08 (19) | | |
Symmetry code: (i) −x+1/2, y, −z+1. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C20H26O4 | C20H26O2 |
Mr | 330.41 | 298.41 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, I2/a |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 7.085 (3), 12.064 (5), 19.583 (5) | 9.415 (8), 10.739 (2), 15.332 (3) |
β (°) | 91.54 (3) | 92.58 (4) |
V (Å3) | 1673.2 (11) | 1548.6 (14) |
Z | 4 | 4 |
Radiation type | Cu Kα | Cu Kα |
µ (mm−1) | 0.73 | 0.63 |
Crystal size (mm) | 0.2 × 0.05 × 0.01 | 0.33 × 0.2 × 0.1 |
|
Data collection |
Diffractometer | Enraf Nonius CAD4 diffractometer | Enraf Nonius CAD4 diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3346, 3054, 1727 | 1724, 1505, 1244 |
Rint | 0.035 | 0.036 |
(sin θ/λ)max (Å−1) | 0.601 | 0.616 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.051, 0.143, 1.02 | 0.040, 0.109, 1.06 |
No. of reflections | 3054 | 1505 |
No. of parameters | 217 | 100 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.19, −0.26 | 0.20, −0.17 |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4B···O20i | 0.97 | 2.47 | 3.366 (4) | 154 |
C19—H19B···O1ii | 0.97 | 2.39 | 3.314 (4) | 159 |
Symmetry codes: (i) −x+1, −y, −z; (ii) −x, −y, −z. |
Ring | Compound | q2Å | conformation |
A | I | 0.284 (3) | Envelope |
B | I | 0.400 (3) | Envelope |
C | I | 0.402 (3) | Envelope |
D | I | 0.411 (3) | Envelope |
E | I | 0.409 (3) | Envelope |
F | I | 0.257 (3) | Twist-Envelope |
A | II | 0.318 (2) | Twist-Envelope |
B | II | 0.399 (2) | Twist-Envelope |
The symmetrical nature of dodecahedrane offers many synthetic routes and there are several ways in which the cyclopentane rings can be assembled (Ternansky et al., 1982; Fessener et al., 1987). However, the strategy developed should involve the fusion of cyclopentane rings with the desired cis stereochemistry. A simple methodology for cyclopentane annulation has been developed to acquire different (C2)-C20 [Foot-note: (C2)-C20 means twofold symmetry in a molecule of twenty atoms] hexaquinanes that are suitable precursors to dodecahedrane (Kotha et al., 1997; Kotha et al., 2002). Although the intermediates can be characterized on the basis of NMR spectral data, the stereochemistry at the ring junctions was ascertained only on the basis of X-ray diffraction analysis.
The structures of (I) and (II) are shown in Fig. 1. The ring junctions are cis fused and the molecules have an 'opened out' conformation. An isomorphous structure solved by McKervey & Siew (1981) also exhibits a cis-fused ring junction, and all the H atoms at the ring junctions point in the same direction. However, in (II), the H atoms at ring junction C/C' are oriented in the opposite direction to all other ring-juction H atoms.
Puckering parameters were calculated using PARST97 (Nardelli, 1995). Five-membered rings A, B, C, D and E in (I) adopt an envelope conformation, but the end five membered ring, viz. F(C17,O17,C20,C19,C18), exhibits a twisted-envelope conformation (Fig. 1). In (II), half a molecule is present in the asymmetric unit, and rings A and B are in a twisted-envelop conformation (Table 1) (Cremer & Pople, 1975). In (I), atoms O1 and O20 lie in the planes through the five-membered rings (Fig. 1) to which they are attached, i.e. rings A and F. However, in (II), atom O8 deviates significantly [0.169 (2) Å] from the plane of ring A.
Ring fusion may be the cause of significant variations from the tetrahedral values for the exocyclic C—C—C bond angles centred at atoms C10, C14, C5, C9, C13 and C6 [121.2 (2), 120.5 (2), 120.3 (2), 121.6 (2), 115.3 (2) and 115.2 (2)°]. Similarly, in (II), the exocyclic bond angles centred at atoms C2, C3, C5, C6 and C7 [115.6 (1), 114.6 (1), 113.0 (1), 117.1 (1) and 117.8 (1)°] differ from the expected tetrahedral values. The packing of (I) is stabilized by weak C—H···O hydrogen bonds (Table 2), while the packing of (II) is stabilized by van der Waals interactions only.