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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

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103010825/na1610sup1.cif
Contains datablocks I, II, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103010825/na1610Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103010825/na1610IIsup3.hkl
Contains datablock II

CCDC references: 162351; 163062

Comment top

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.

Experimental top

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.

Refinement top

H atoms were fixed geometrically at calculated position.

Computing details top

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).

Figures top
[Figure 1]
Scheme 1

Scheme 2

I. Chemical diagram of the title compounds.

Fig. 1. A view of the molecular structure of (I) and (II), showing displacement ellipsoids at the 50% probability level and the atomic numbering scheme.
(I) (2R,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
C20H26O4F(000) = 712
Mr = 330.41Dx = 1.312 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.5418 Å
a = 7.085 (3) ÅCell parameters from 25 reflections
b = 12.064 (5) Åθ = 8.6–25.6°
c = 19.583 (5) ŵ = 0.73 mm1
β = 91.54 (3)°T = 293 K
V = 1673.2 (11) Å3Rectangular needle, colourless
Z = 40.2 × 0.05 × 0.01 mm
Data collection top
Enraf Nonius CAD4
diffractometer
Rint = 0.035
Radiation source: fine-focus sealed tubeθmax = 68.0°, θmin = 4.3°
Graphite monochromatorh = 08
non–profiled ω/2θ scansk = 014
3346 measured reflectionsl = 2323
3054 independent reflections3 standard reflections every 200 reflections
1727 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.051Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.143H-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 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.26 e Å3
Crystal data top
C20H26O4V = 1673.2 (11) Å3
Mr = 330.41Z = 4
Monoclinic, P21/cCu Kα radiation
a = 7.085 (3) ŵ = 0.73 mm1
b = 12.064 (5) ÅT = 293 K
c = 19.583 (5) Å0.2 × 0.05 × 0.01 mm
β = 91.54 (3)°
Data collection top
Enraf Nonius CAD4
diffractometer
Rint = 0.035
3346 measured reflections3 standard reflections every 200 reflections
3054 independent reflections intensity decay: none
1727 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0510 restraints
wR(F2) = 0.143H-atom parameters constrained
S = 1.02Δρmax = 0.19 e Å3
3054 reflectionsΔρmin = 0.26 e Å3
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
xyzUiso*/Ueq
O10.2004 (3)0.24033 (19)0.20409 (12)0.0728 (7)
C10.0355 (4)0.2188 (2)0.20106 (14)0.0488 (7)
C20.2323 (3)0.1092 (2)0.20137 (13)0.0405 (6)
O20.0273 (2)0.11409 (15)0.20733 (9)0.0478 (5)
C30.2948 (4)0.2295 (2)0.21526 (15)0.0462 (7)
H3A0.32400.24100.26340.055*
H3B0.40460.24840.18910.055*
C40.1260 (4)0.2962 (2)0.19243 (15)0.0496 (7)
H4A0.11240.36180.22060.059*
H4B0.13570.31870.14510.059*
C50.2923 (3)0.0675 (2)0.13113 (13)0.0419 (6)
H50.31610.13170.10190.050*
C60.4822 (4)0.0068 (2)0.14596 (15)0.0493 (7)
H60.58520.04660.12430.059*
C70.5126 (4)0.0079 (2)0.22367 (15)0.0600 (8)
H7A0.56380.06240.23960.072*
H7B0.59890.06670.23750.072*
C80.3177 (4)0.0277 (2)0.25244 (14)0.0515 (7)
H8A0.24500.04040.25380.062*
H8B0.32650.05940.29790.062*
C90.1680 (3)0.0155 (2)0.09083 (13)0.0442 (7)
H90.09530.02410.05520.053*
C100.3085 (4)0.0943 (2)0.05733 (13)0.0460 (7)
H100.36420.05710.01820.055*
C110.4588 (4)0.1083 (2)0.11381 (17)0.0579 (8)
H11A0.57680.13350.09510.069*
H11B0.41830.16170.14750.069*
C120.0392 (3)0.0969 (2)0.12675 (14)0.0500 (7)
H12A0.08010.06220.13720.060*
H12B0.09840.12360.16890.060*
C130.0089 (4)0.1925 (2)0.07562 (14)0.0464 (7)
H130.10300.17790.04650.056*
C140.1889 (3)0.1929 (2)0.03174 (13)0.0407 (6)
H140.15120.17990.01610.049*
C150.0047 (4)0.3076 (2)0.10727 (16)0.0599 (8)
H15A0.05040.30310.15340.072*
H15B0.08930.35450.08030.072*
C160.1958 (4)0.3528 (2)0.10732 (14)0.0566 (8)
H16A0.27180.32260.14490.068*
H16B0.19710.43310.11000.068*
C170.2644 (3)0.3126 (2)0.03896 (13)0.0443 (7)
O170.4702 (2)0.31673 (16)0.03668 (10)0.0527 (5)
C180.2010 (4)0.3864 (2)0.02122 (14)0.0536 (7)
H18A0.18050.46210.00630.064*
H18B0.08560.35860.04270.064*
C190.3625 (4)0.3801 (3)0.06916 (16)0.0665 (9)
H19A0.38360.45120.09070.080*
H19B0.33820.32490.10440.080*
C200.5273 (4)0.3479 (2)0.02507 (15)0.0527 (7)
O200.6920 (3)0.3480 (2)0.03866 (11)0.0730 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0437 (12)0.0678 (15)0.1068 (19)0.0111 (11)0.0004 (11)0.0000 (13)
C10.0408 (16)0.0489 (17)0.0565 (17)0.0064 (13)0.0042 (13)0.0015 (13)
C20.0325 (13)0.0391 (14)0.0500 (15)0.0008 (11)0.0021 (11)0.0006 (12)
O20.0374 (10)0.0441 (11)0.0622 (12)0.0024 (8)0.0056 (8)0.0051 (9)
C30.0427 (15)0.0399 (15)0.0561 (17)0.0015 (12)0.0017 (12)0.0054 (13)
C40.0509 (17)0.0364 (15)0.0616 (18)0.0019 (13)0.0034 (14)0.0000 (13)
C50.0453 (15)0.0343 (13)0.0462 (15)0.0002 (12)0.0050 (12)0.0044 (12)
C60.0354 (14)0.0425 (16)0.0702 (19)0.0043 (12)0.0054 (13)0.0103 (14)
C70.0506 (17)0.0489 (18)0.080 (2)0.0092 (14)0.0148 (16)0.0092 (16)
C80.0608 (18)0.0437 (16)0.0494 (16)0.0029 (14)0.0087 (14)0.0028 (13)
C90.0450 (15)0.0405 (14)0.0468 (15)0.0070 (12)0.0047 (12)0.0021 (12)
C100.0462 (15)0.0456 (16)0.0469 (15)0.0043 (13)0.0133 (12)0.0007 (12)
C110.0293 (14)0.0531 (18)0.091 (2)0.0031 (13)0.0004 (14)0.0208 (17)
C120.0320 (14)0.0576 (18)0.0609 (18)0.0016 (13)0.0081 (12)0.0139 (14)
C130.0364 (15)0.0520 (16)0.0506 (16)0.0026 (12)0.0023 (12)0.0081 (13)
C140.0412 (15)0.0432 (15)0.0375 (14)0.0031 (12)0.0007 (11)0.0025 (12)
C150.063 (2)0.0607 (19)0.0568 (18)0.0168 (16)0.0125 (15)0.0052 (15)
C160.075 (2)0.0422 (16)0.0525 (18)0.0051 (15)0.0027 (15)0.0036 (13)
C170.0376 (15)0.0446 (15)0.0506 (16)0.0020 (12)0.0014 (12)0.0033 (13)
O170.0419 (11)0.0549 (12)0.0610 (12)0.0076 (9)0.0047 (9)0.0124 (10)
C180.0569 (18)0.0457 (16)0.0578 (18)0.0030 (14)0.0057 (14)0.0107 (14)
C190.063 (2)0.084 (2)0.0526 (18)0.0077 (18)0.0038 (15)0.0099 (17)
C200.0525 (18)0.0504 (17)0.0555 (18)0.0083 (14)0.0045 (15)0.0014 (14)
O200.0526 (13)0.0873 (17)0.0798 (16)0.0118 (12)0.0114 (11)0.0001 (12)
Geometric parameters (Å, º) top
O1—C11.200 (3)C10—H100.9800
C1—O21.344 (3)C11—H11A0.9700
C1—C41.490 (4)C11—H11B0.9700
C2—O21.462 (3)C12—C131.538 (4)
C2—C81.517 (4)C12—H12A0.9700
C2—C51.535 (3)C12—H12B0.9700
C2—C31.539 (3)C13—C151.525 (4)
C3—C41.501 (4)C13—C141.557 (3)
C3—H3A0.9700C13—H130.9800
C3—H3B0.9700C14—C171.545 (4)
C4—H4A0.9700C14—H140.9800
C4—H4B0.9700C15—C161.522 (4)
C5—C91.537 (3)C15—H15A0.9700
C5—C61.552 (3)C15—H15B0.9700
C5—H50.9800C16—C171.516 (4)
C6—C71.531 (4)C16—H16A0.9700
C6—C111.533 (4)C16—H16B0.9700
C6—H60.9800C17—O171.461 (3)
C7—C81.524 (4)C17—C181.535 (4)
C7—H7A0.9700O17—C201.340 (3)
C7—H7B0.9700C18—C191.501 (4)
C8—H8A0.9700C18—H18A0.9700
C8—H8B0.9700C18—H18B0.9700
C9—C121.526 (4)C19—C201.485 (4)
C9—C101.536 (3)C19—H19A0.9700
C9—H90.9800C19—H19B0.9700
C10—C111.524 (4)C20—O201.203 (3)
C10—C141.537 (4)
O1—C1—O2121.3 (3)C10—C11—C6105.2 (2)
O1—C1—C4128.5 (3)C10—C11—H11A110.7
O2—C1—C4110.3 (2)C6—C11—H11A110.7
O2—C2—C8110.7 (2)C10—C11—H11B110.7
O2—C2—C5112.6 (2)C6—C11—H11B110.7
C8—C2—C5105.3 (2)H11A—C11—H11B108.8
O2—C2—C3103.27 (19)C9—C12—C13104.9 (2)
C8—C2—C3112.8 (2)C9—C12—H12A110.8
C5—C2—C3112.4 (2)C13—C12—H12A110.8
C1—O2—C2111.0 (2)C9—C12—H12B110.8
C4—C3—C2103.3 (2)C13—C12—H12B110.8
C4—C3—H3A111.1H12A—C12—H12B108.8
C2—C3—H3A111.1C15—C13—C12115.3 (2)
C4—C3—H3B111.1C15—C13—C14106.4 (2)
C2—C3—H3B111.1C12—C13—C14105.1 (2)
H3A—C3—H3B109.1C15—C13—H13109.9
C1—C4—C3103.8 (2)C12—C13—H13109.9
C1—C4—H4A111.0C14—C13—H13109.9
C3—C4—H4A111.0C10—C14—C17120.5 (2)
C1—C4—H4B111.0C10—C14—C13105.7 (2)
C3—C4—H4B111.0C17—C14—C13103.9 (2)
H4A—C4—H4B109.0C10—C14—H14108.8
C2—C5—C9120.3 (2)C17—C14—H14108.8
C2—C5—C6104.2 (2)C13—C14—H14108.8
C9—C5—C6105.7 (2)C16—C15—C13104.9 (2)
C2—C5—H5108.7C16—C15—H15A110.8
C9—C5—H5108.7C13—C15—H15A110.8
C6—C5—H5108.7C16—C15—H15B110.8
C7—C6—C11115.2 (2)C13—C15—H15B110.8
C7—C6—C5106.3 (2)H15A—C15—H15B108.8
C11—C6—C5105.5 (2)C17—C16—C15101.9 (2)
C7—C6—H6109.9C17—C16—H16A111.4
C11—C6—H6109.9C15—C16—H16A111.4
C5—C6—H6109.9C17—C16—H16B111.4
C8—C7—C6105.3 (2)C15—C16—H16B111.4
C8—C7—H7A110.7H16A—C16—H16B109.3
C6—C7—H7A110.7O17—C17—C16111.1 (2)
C8—C7—H7B110.7O17—C17—C18103.2 (2)
C6—C7—H7B110.7C16—C17—C18113.4 (2)
H7A—C7—H7B108.8O17—C17—C14111.9 (2)
C2—C8—C7102.0 (2)C16—C17—C14105.1 (2)
C2—C8—H8A111.4C18—C17—C14112.2 (2)
C7—C8—H8A111.4C20—O17—C17111.3 (2)
C2—C8—H8B111.4C19—C18—C17103.8 (2)
C7—C8—H8B111.4C19—C18—H18A111.0
H8A—C8—H8B109.2C17—C18—H18A111.0
C12—C9—C10101.6 (2)C19—C18—H18B111.0
C12—C9—C5121.6 (2)C17—C18—H18B111.0
C10—C9—C5104.7 (2)H18A—C18—H18B109.0
C12—C9—H9109.4C20—C19—C18104.5 (2)
C10—C9—H9109.4C20—C19—H19A110.9
C5—C9—H9109.4C18—C19—H19A110.9
C11—C10—C9102.0 (2)C20—C19—H19B110.9
C11—C10—C14121.2 (2)C18—C19—H19B110.9
C9—C10—C14105.1 (2)H19A—C19—H19B108.9
C11—C10—H10109.3O20—C20—O17121.2 (3)
C9—C10—H10109.3O20—C20—C19128.5 (3)
C14—C10—H10109.3O17—C20—C19110.2 (2)
O1—C1—O2—C2179.6 (3)C7—C6—C11—C10141.7 (2)
C4—C1—O2—C21.9 (3)C5—C6—C11—C1024.8 (3)
C8—C2—O2—C1139.9 (2)C10—C9—C12—C1341.1 (3)
C5—C2—O2—C1102.5 (2)C5—C9—C12—C13156.6 (2)
C3—C2—O2—C119.0 (3)C9—C12—C13—C15144.2 (2)
O2—C2—C3—C427.9 (3)C9—C12—C13—C1427.4 (3)
C8—C2—C3—C4147.4 (2)C11—C10—C14—C1725.1 (4)
C5—C2—C3—C493.7 (2)C9—C10—C14—C17139.6 (2)
O1—C1—C4—C3161.9 (3)C11—C10—C14—C1391.9 (3)
O2—C1—C4—C316.5 (3)C9—C10—C14—C1322.6 (3)
C2—C3—C4—C126.8 (3)C15—C13—C14—C10125.5 (2)
O2—C2—C5—C931.0 (3)C12—C13—C14—C102.8 (3)
C8—C2—C5—C989.7 (3)C15—C13—C14—C172.2 (3)
C3—C2—C5—C9147.1 (2)C12—C13—C14—C17124.9 (2)
O2—C2—C5—C6149.1 (2)C12—C13—C15—C1692.9 (3)
C8—C2—C5—C628.4 (2)C14—C13—C15—C1623.1 (3)
C3—C2—C5—C694.7 (2)C13—C15—C16—C1739.6 (3)
C2—C5—C6—C74.8 (3)C15—C16—C17—O17162.5 (2)
C9—C5—C6—C7123.0 (2)C15—C16—C17—C1881.8 (3)
C2—C5—C6—C11127.6 (2)C15—C16—C17—C1441.3 (3)
C9—C5—C6—C110.2 (3)C10—C14—C17—O1729.7 (3)
C11—C6—C7—C896.1 (3)C13—C14—C17—O17147.6 (2)
C5—C6—C7—C820.4 (3)C10—C14—C17—C1691.0 (3)
O2—C2—C8—C7162.9 (2)C13—C14—C17—C1626.9 (2)
C5—C2—C8—C741.0 (3)C10—C14—C17—C18145.2 (2)
C3—C2—C8—C781.9 (3)C13—C14—C17—C1896.9 (2)
C6—C7—C8—C237.6 (3)C16—C17—O17—C20142.3 (2)
C2—C5—C9—C1227.8 (3)C18—C17—O17—C2020.4 (3)
C6—C5—C9—C1289.6 (3)C14—C17—O17—C20100.5 (2)
C2—C5—C9—C10141.7 (2)O17—C17—C18—C1926.0 (3)
C6—C5—C9—C1024.3 (3)C16—C17—C18—C19146.3 (2)
C12—C9—C10—C1188.0 (2)C14—C17—C18—C1994.7 (3)
C5—C9—C10—C1139.3 (3)C17—C18—C19—C2022.8 (3)
C12—C9—C10—C1439.3 (3)C17—O17—C20—O20174.2 (3)
C5—C9—C10—C14166.7 (2)C17—O17—C20—C196.1 (3)
C9—C10—C11—C639.6 (3)C18—C19—C20—O20168.4 (3)
C14—C10—C11—C6155.8 (2)C18—C19—C20—O1711.3 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4B···O20i0.972.473.366 (4)154
C19—H19B···O1ii0.972.393.314 (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
C20H26O2F(000) = 648
Mr = 298.41Dx = 1.280 Mg m3
Monoclinic, I2/aCu Kα radiation, λ = 1.5418 Å
a = 9.415 (8) ÅCell parameters from 25 reflections
b = 10.739 (2) Åθ = 22.1–28.6°
c = 15.332 (3) ŵ = 0.63 mm1
β = 92.58 (4)°T = 293 K
V = 1548.6 (14) Å3Rectangle, colourless
Z = 40.33 × 0.2 × 0.1 mm
Data collection top
Enraf Nonius CAD4
diffractometer
Rint = 0.036
Radiation source: fine-focus sealed tubeθmax = 71.9°, θmin = 5.0°
Graphite monochromatorh = 111
non–profiled ω/2θ scansk = 013
1724 measured reflectionsl = 1818
1505 independent reflections3 standard reflections every 200 reflections
1244 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.109H-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 parametersΔρmax = 0.20 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C20H26O2V = 1548.6 (14) Å3
Mr = 298.41Z = 4
Monoclinic, I2/aCu Kα radiation
a = 9.415 (8) ŵ = 0.63 mm1
b = 10.739 (2) ÅT = 293 K
c = 15.332 (3) Å0.33 × 0.2 × 0.1 mm
β = 92.58 (4)°
Data collection top
Enraf Nonius CAD4
diffractometer
Rint = 0.036
1724 measured reflections3 standard reflections every 200 reflections
1505 independent reflections intensity decay: none
1244 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.109H-atom parameters constrained
S = 1.06Δρmax = 0.20 e Å3
1505 reflectionsΔρmin = 0.17 e Å3
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
xyzUiso*/Ueq
C10.27172 (16)0.87046 (14)0.59610 (10)0.0363 (4)
H1A0.23070.95000.57870.044*
H1B0.25570.85710.65750.044*
C20.20445 (15)0.76450 (13)0.54048 (8)0.0316 (3)
H20.21140.68470.57140.038*
C30.05300 (15)0.78815 (13)0.50439 (9)0.0323 (3)
H30.00130.83370.54710.039*
C40.02773 (16)0.67118 (14)0.47388 (10)0.0370 (4)
H4A0.08140.63650.52060.044*
H4B0.03710.60830.45360.044*
C50.12755 (16)0.71772 (14)0.39862 (10)0.0365 (4)
H50.21100.76020.42030.044*
C60.03230 (15)0.80764 (14)0.34959 (9)0.0343 (3)
H60.09070.87180.31990.041*
C70.06809 (16)0.86823 (13)0.42006 (9)0.0334 (3)
H70.03570.95330.43120.040*
C80.16925 (19)0.61669 (16)0.33417 (11)0.0475 (4)
O80.26489 (17)0.54259 (15)0.34168 (10)0.0782 (5)
C90.0749 (2)0.62503 (19)0.25785 (13)0.0573 (5)
H9A0.12980.64890.20540.069*
H9B0.02990.54540.24770.069*
C100.03653 (18)0.72361 (16)0.28153 (10)0.0445 (4)
H10A0.05980.77140.23040.053*
H10B0.12270.68540.30610.053*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0414 (8)0.0343 (8)0.0333 (7)0.0025 (6)0.0030 (6)0.0049 (6)
C20.0368 (8)0.0291 (7)0.0290 (7)0.0000 (6)0.0045 (6)0.0017 (6)
C30.0366 (8)0.0299 (7)0.0309 (7)0.0011 (6)0.0060 (6)0.0003 (6)
C40.0387 (8)0.0324 (8)0.0400 (8)0.0021 (6)0.0030 (6)0.0047 (6)
C50.0351 (8)0.0345 (8)0.0400 (8)0.0002 (6)0.0021 (6)0.0007 (6)
C60.0377 (8)0.0307 (7)0.0345 (7)0.0049 (6)0.0010 (6)0.0024 (6)
C70.0409 (8)0.0251 (7)0.0343 (7)0.0035 (6)0.0037 (6)0.0012 (6)
C80.0516 (10)0.0387 (9)0.0511 (10)0.0028 (8)0.0112 (8)0.0016 (7)
O80.0887 (11)0.0684 (10)0.0768 (10)0.0395 (9)0.0052 (8)0.0070 (8)
C90.0584 (11)0.0575 (11)0.0554 (11)0.0040 (9)0.0035 (9)0.0217 (9)
C100.0467 (9)0.0491 (9)0.0378 (8)0.0045 (8)0.0034 (7)0.0070 (7)
Geometric parameters (Å, º) top
C1—C7i1.540 (2)C5—C61.537 (2)
C1—C21.541 (2)C5—H50.9800
C1—H1A0.9700C6—C101.544 (2)
C1—H1B0.9700C6—C71.547 (2)
C2—C31.527 (2)C6—H60.9800
C2—C2i1.540 (3)C7—C1i1.540 (2)
C2—H20.9800C7—H70.9800
C3—C41.531 (2)C8—O81.211 (2)
C3—C71.5647 (19)C8—C91.503 (3)
C3—H30.9800C9—C101.523 (3)
C4—C51.538 (2)C9—H9A0.9700
C4—H4A0.9700C9—H9B0.9700
C4—H4B0.9700C10—H10A0.9700
C5—C81.508 (2)C10—H10B0.9700
C7i—C1—C2106.30 (12)C4—C5—H5111.6
C7i—C1—H1A110.5C5—C6—C10103.60 (13)
C2—C1—H1A110.5C5—C6—C7105.93 (12)
C7i—C1—H1B110.5C10—C6—C7117.14 (13)
C2—C1—H1B110.5C5—C6—H6109.9
H1A—C1—H1B108.7C10—C6—H6109.9
C3—C2—C2i104.64 (14)C7—C6—H6109.9
C3—C2—C1115.56 (12)C1i—C7—C6117.80 (13)
C2i—C2—C1102.48 (11)C1i—C7—C3105.52 (12)
C3—C2—H2111.2C6—C7—C3105.70 (11)
C2i—C2—H2111.2C1i—C7—H7109.2
C1—C2—H2111.2C6—C7—H7109.2
C2—C3—C4114.64 (12)C3—C7—H7109.2
C2—C3—C7105.83 (12)O8—C8—C9125.52 (17)
C4—C3—C7105.12 (11)O8—C8—C5125.69 (17)
C2—C3—H3110.3C9—C8—C5108.77 (14)
C4—C3—H3110.3C8—C9—C10106.30 (14)
C7—C3—H3110.3C8—C9—H9A110.5
C3—C4—C5103.94 (12)C10—C9—H9A110.5
C3—C4—H4A111.0C8—C9—H9B110.5
C5—C4—H4A111.0C10—C9—H9B110.5
C3—C4—H4B111.0H9A—C9—H9B108.7
C5—C4—H4B111.0C9—C10—C6105.17 (14)
H4A—C4—H4B109.0C9—C10—H10A110.7
C8—C5—C6105.79 (12)C6—C10—H10A110.7
C8—C5—C4112.96 (13)C9—C10—H10B110.7
C6—C5—C4102.75 (12)C6—C10—H10B110.7
C8—C5—H5111.6H10A—C10—H10B108.8
C6—C5—H5111.6
C7i—C1—C2—C3147.29 (12)C5—C6—C7—C313.43 (14)
C7i—C1—C2—C2i34.16 (15)C10—C6—C7—C3101.46 (15)
C2i—C2—C3—C485.77 (11)C2—C3—C7—C1i8.23 (14)
C1—C2—C3—C4162.36 (12)C4—C3—C7—C1i113.47 (13)
C2i—C2—C3—C729.58 (10)C2—C3—C7—C6133.75 (12)
C1—C2—C3—C782.28 (14)C4—C3—C7—C612.05 (14)
C2—C3—C4—C5148.74 (12)C6—C5—C8—O8164.54 (18)
C7—C3—C4—C532.97 (15)C4—C5—C8—O883.8 (2)
C3—C4—C5—C8154.73 (13)C6—C5—C8—C914.04 (18)
C3—C4—C5—C641.22 (14)C4—C5—C8—C997.61 (17)
C8—C5—C6—C1028.40 (15)O8—C8—C9—C10175.07 (18)
C4—C5—C6—C1090.26 (13)C5—C8—C9—C106.35 (19)
C8—C5—C6—C7152.25 (12)C8—C9—C10—C624.14 (18)
C4—C5—C6—C733.59 (14)C5—C6—C10—C932.34 (16)
C5—C6—C7—C1i130.98 (13)C7—C6—C10—C9148.52 (14)
C10—C6—C7—C1i16.08 (19)
Symmetry code: (i) x+1/2, y, z+1.

Experimental details

(I)(II)
Crystal data
Chemical formulaC20H26O4C20H26O2
Mr330.41298.41
Crystal system, space groupMonoclinic, P21/cMonoclinic, I2/a
Temperature (K)293293
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)
V3)1673.2 (11)1548.6 (14)
Z44
Radiation typeCu KαCu Kα
µ (mm1)0.730.63
Crystal size (mm)0.2 × 0.05 × 0.010.33 × 0.2 × 0.1
Data collection
DiffractometerEnraf 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
Rint0.0350.036
(sin θ/λ)max1)0.6010.616
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.051, 0.143, 1.02 0.040, 0.109, 1.06
No. of reflections30541505
No. of parameters217100
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.19, 0.260.20, 0.17

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1995), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Johnson & Burnett, 1996; Farrugia, 1999), ORTEP-3(Johnson & Burnett, 1996; Farrugia, 1999).

Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
C4—H4B···O20i0.972.473.366 (4)154
C19—H19B···O1ii0.972.393.314 (4)159
Symmetry codes: (i) x+1, y, z; (ii) x, y, z.
RingCompoundq2Åconformation
AI0.284 (3)Envelope
BI0.400 (3)Envelope
CI0.402 (3)Envelope
DI0.411 (3)Envelope
EI0.409 (3)Envelope
FI0.257 (3)Twist-Envelope
AII0.318 (2)Twist-Envelope
BII0.399 (2)Twist-Envelope
 

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