organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

cis,trans,cis,cis-7-tert-Butyl­di­methyl­silyl­­oxy-4,10-di­methyl­tetra­cyclo[5.4.1.04,12.010,12]dodecan-2-one

aDepartment of Chemistry and Biochemistry, University Bern, Freiestrasse 3, CH-3012 Bern, Switzerland, and bInstitute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland
*Correspondence e-mail: reinhart.keese@ioc.unibe.ch

(Received 6 January 2010; accepted 7 January 2010; online 13 January 2010)

In the structure of the title compound, C20H34O2Si, a cis,trans,cis,cis-[4.5.5.5]fenestrane derivative, the geometry of the central C(C)4 substructure shows considerable distortion from an ideal tetra­hedral arrangement towards planarity, with two opposite bridgehead bond angles of 128.87 (18) and 122.83 (17)°. The other bridgehead angle of the trans-bicyclo­[3.3.0]octane subunit is also large [126.57 (19)°].

Related literature

For the synthesis and structures of related compounds, see: Thommen et al. (1996[Thommen, M., Keese, R. & Förtsch, M. (1996). Acta Cryst. C52, 2051-2053.]); Wang et al. (1996[Wang, J., Thommen, M. & Keese, R. (1996). Acta Cryst. C52, 2311-2313.]); Weyermann (1997[Weyermann, P. (1997). Diploma thesis, University of Bern, Switzerland.]); Weyermann & Keese (2010[Weyermann, P. & Keese, R. (2010). In preparation.]). For information on planarizing distortions in the central C(C)4 moiety, see: Keese (2006[Keese, R. (2006). Chem. Rev. 106, 4787-4808.]). For methods to enhance the planarizing distortions in the central C(C)4 substructure, see: Luef & Keese (1993[Luef, W. & Keese, R. (1993). Advances in Strain in Organic Chemistry, Vol. 3, edited by B. Halton, pp. 229-267. London: JAI Press.]). For an analysis of the bond angles and other details concerning trans-fused bicyclo­[3.3.0]octa­nes, see: Hirschi et al. (1992[Hirschi, D., Luef, W., Gerber, P. & Keese, R. (1992). Helv. Chim. Acta, 75, 1897-1908.]). For information concerning the Pauson–Khand reaction, see: Khand, Knox, Pauson & Watts (1973[Khand, I. U., Knox, G. R., Pauson, P. L. & Watts, W. E. (1973). J. Chem. Soc. Perkin Trans. 1, pp. 977-977.]); Khand, Knox, Pauson, Watts & Foreman (1973[Khand, I. U., Knox, G. R., Pauson, P. L., Watts, W. E. & Foreman, M. I. (1973). J. Chem. Soc. Perkin Trans. 1, pp. 977-981.]).

[Scheme 1]

Experimental

Crystal data
  • C20H34O2Si

  • Mr = 334.56

  • Orthorhombic, P b c a

  • a = 13.7374 (13) Å

  • b = 14.7647 (11) Å

  • c = 19.2829 (12) Å

  • V = 3911.1 (5) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.13 mm−1

  • T = 223 K

  • 0.53 × 0.42 × 0.34 mm

Data collection
  • Stoe AED2 four-circle diffractometer

  • 7284 measured reflections

  • 3642 independent reflections

  • 2718 reflections with I > 2σ(I)

  • Rint = 0.042

  • 3 standard reflections every 60 min intensity decay: <1%

Refinement
  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.116

  • S = 1.07

  • 3642 reflections

  • 216 parameters

  • H-atom parameters constrained

  • Δρmax = 0.28 e Å−3

  • Δρmin = −0.29 e Å−3

Data collection: STADI-4 (Stoe & Cie, 1997[Stoe & Cie (1997). STADI-4 and X-RED. Stoe & Cie GmbH, Damstadt, Germany.]); cell refinement: STADI-4; data reduction: X-RED (Stoe & Cie, 1997[Stoe & Cie (1997). STADI-4 and X-RED. Stoe & Cie GmbH, Damstadt, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Fenestranes are a unique class of hydrocarbons and contain a quaternary C atom in the center of the tetracyclic structure. These compounds are of interest for the planarizing distortions in the central C(C)4 moiety, apparent in two opposite bond angles larger than the bond angle of 109.47° in a regular tetrahedral arrangement (Keese, 2006). Systematic investigations of the structural features in a variety of such molecules by semiempirical methods have revealed that they can be enhanced by ring contraction, inversion at one (or more) of the four bridgehead centers, giving rise to a trans-fused bicylo[3.3.0]octane subunit, by introduction of a bridgehead double bond (Luef & Keese, 1993) and by alkyl groups at the peripheral bridgehead positions. As part of our efforts to prepare fenestranes with a combination of structural features for enhanced planarizing distortions we have prepared the title compound, (3), from the yne-diene (1) by a Co2(CO)8-induced cyclocarbonylation reaction (Pauson-Khand reaction - Khand et al., 1973a, 1973b) followed by a photoinduced intramolecular olefin-enone cyclo-addition of (2) [see Scheme 2] (Weyermann, 1997; Weyermann & Keese, 2010).

The molecular structure of the title compound (3) is illustrated in Fig. 1, and geometrical parameters are given in the Supplementary information and the archived CIF. In (3) the bridgehead bond angles C1—C12—C7 and C4—C12—C10 are 128.87 (18)° and 122.83 (17)°, respectively. In comparison in compound (4), the cis,trans,cis,cis [4.5.5.5]fenestrane without the methyl groups at the bridgehead positions C4 and C10 (Thommen et al., 1996), the same bridgehead bond angles are 131.1 (2)° and 120.2 (2)°, respectively. In the related cis,trans,cis,cis[4.5.5.5.]fenestrene (5), bearing only one bridgehead substituent at C4, the bridgehead bond angles are slightly different to those in (3) and (4); C1—C12—C7 and C4—C12—C10 are 134.9 (2)° and 119.2 (2)°, respectively (Wang et al., 1996).

An earlier analysis of the bond angles in trans-fused bicyclo[3.3.0]octanes (Hirschi et al., 1992) revealed that the bond angles at the bridgehead centres are always larger than the normal tetrahedral angle. In line with these findings in (3) bond angle C3—C4—C5 is 126.57 (19)°, and 127.0 (2)° in (4).

Salient features in (3) are the bond distances and angles involving the methyl substituents C13 and C14. Bonds C4—C13 and C10—C14 are 1.548 (3) and 1.526 (3) Å, respectively, while bond angles C12—C4—C13 and C12—C10—C14 are 111.99 (18) and 124.53 (18)°, respectively. The torsional angles C13—C4—C12—C10 and C14—C10—C12—C4 are -173.39 (19) and 9.9 (3)°, respectively, indicating that the deviation from a strictly ecliptic orientation is rather small.

In conclusion it can be seen that the introduction of the methyl substituents in (3) hardly enhances the planoid distortions in the central C(C)4 substructure. Apparently accumulation of three quaternary C-atoms, adjacent to one another in the tetracyclic fenestrane (3), leads to a different adjustment of the steric interactions.

Related literature top

For the synthesis and structures of related compounds, see: Thommen et al. (1996); Wang et al. (1996); Weyermann (1997); Weyermann & Keese (2010). For information on planarizing distortions in the central C(C)4 moiety, see: Keese (2006). For methods to enhance the planarizing distortions in the central C(C)4 substructure, see: Luef & Keese (1993). For an analysis of the bond angles and other details concerning trans-fused bicyclo[3.3.0]octanes, see: Hirschi et al. (1992). For information concerning the Pauson–Khand reaction, see: Khand, Knox, Pauson & Watts (1973); Khand, Knox, Pauson, Watts & Foreman (1973).

Experimental top

The synthesis of the title compound, (3), is illustrated in Fig. 2. 2,8-dimethyl-5-ethinyl-5-(tert.-butyldimethylsilyloxy =OTBDMS)-1,8-nonadiene (1) was treated with 1.15 molequivalent of Co2(CO)8 in tetrahydrofuran/CH2Cl2 (1:1) and N-methylmorpholine-N oxide (NMO) at r.t. to give the enone (2), together with another diastereomer. Irradiation with UV light (254 nm) gave the title fenestranone (3) in 79% isolated yield. Colourless needle-like crystals of (3) were obtained by crystallization from hexane at 253 K (m.p. 356–348 K).

Refinement top

The H-atoms were included in calculated positions and treated as riding atoms: C—H = 0.97 - 0.99 Å with Uiso(H) = k × Ueq(C), where k = 1.2 for CH and CH2 H-atoms and 1.5 for methyl H-atoms.

Structure description top

Fenestranes are a unique class of hydrocarbons and contain a quaternary C atom in the center of the tetracyclic structure. These compounds are of interest for the planarizing distortions in the central C(C)4 moiety, apparent in two opposite bond angles larger than the bond angle of 109.47° in a regular tetrahedral arrangement (Keese, 2006). Systematic investigations of the structural features in a variety of such molecules by semiempirical methods have revealed that they can be enhanced by ring contraction, inversion at one (or more) of the four bridgehead centers, giving rise to a trans-fused bicylo[3.3.0]octane subunit, by introduction of a bridgehead double bond (Luef & Keese, 1993) and by alkyl groups at the peripheral bridgehead positions. As part of our efforts to prepare fenestranes with a combination of structural features for enhanced planarizing distortions we have prepared the title compound, (3), from the yne-diene (1) by a Co2(CO)8-induced cyclocarbonylation reaction (Pauson-Khand reaction - Khand et al., 1973a, 1973b) followed by a photoinduced intramolecular olefin-enone cyclo-addition of (2) [see Scheme 2] (Weyermann, 1997; Weyermann & Keese, 2010).

The molecular structure of the title compound (3) is illustrated in Fig. 1, and geometrical parameters are given in the Supplementary information and the archived CIF. In (3) the bridgehead bond angles C1—C12—C7 and C4—C12—C10 are 128.87 (18)° and 122.83 (17)°, respectively. In comparison in compound (4), the cis,trans,cis,cis [4.5.5.5]fenestrane without the methyl groups at the bridgehead positions C4 and C10 (Thommen et al., 1996), the same bridgehead bond angles are 131.1 (2)° and 120.2 (2)°, respectively. In the related cis,trans,cis,cis[4.5.5.5.]fenestrene (5), bearing only one bridgehead substituent at C4, the bridgehead bond angles are slightly different to those in (3) and (4); C1—C12—C7 and C4—C12—C10 are 134.9 (2)° and 119.2 (2)°, respectively (Wang et al., 1996).

An earlier analysis of the bond angles in trans-fused bicyclo[3.3.0]octanes (Hirschi et al., 1992) revealed that the bond angles at the bridgehead centres are always larger than the normal tetrahedral angle. In line with these findings in (3) bond angle C3—C4—C5 is 126.57 (19)°, and 127.0 (2)° in (4).

Salient features in (3) are the bond distances and angles involving the methyl substituents C13 and C14. Bonds C4—C13 and C10—C14 are 1.548 (3) and 1.526 (3) Å, respectively, while bond angles C12—C4—C13 and C12—C10—C14 are 111.99 (18) and 124.53 (18)°, respectively. The torsional angles C13—C4—C12—C10 and C14—C10—C12—C4 are -173.39 (19) and 9.9 (3)°, respectively, indicating that the deviation from a strictly ecliptic orientation is rather small.

In conclusion it can be seen that the introduction of the methyl substituents in (3) hardly enhances the planoid distortions in the central C(C)4 substructure. Apparently accumulation of three quaternary C-atoms, adjacent to one another in the tetracyclic fenestrane (3), leads to a different adjustment of the steric interactions.

For the synthesis and structures of related compounds, see: Thommen et al. (1996); Wang et al. (1996); Weyermann (1997); Weyermann & Keese (2010). For information on planarizing distortions in the central C(C)4 moiety, see: Keese (2006). For methods to enhance the planarizing distortions in the central C(C)4 substructure, see: Luef & Keese (1993). For an analysis of the bond angles and other details concerning trans-fused bicyclo[3.3.0]octanes, see: Hirschi et al. (1992). For information concerning the Pauson–Khand reaction, see: Khand, Knox, Pauson & Watts (1973); Khand, Knox, Pauson, Watts & Foreman (1973).

Computing details top

Data collection: STADI-4 (Stoe & Cie, 1997); cell refinement: STADI-4 (Stoe & Cie, 1997); data reduction: X-RED (Stoe & Cie, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of compound (3), with displacement ellipsoids drawn at the 50% probability level [the H-atoms have been omitted for clarity].
[Figure 2] Fig. 2. The synthesis of the title compound.
cis,trans,cis,cis-7-tert- Butyldimethylsilyloxy-4,10-dimethyltetracyclo[5.4.1.04,12.010,12]dodecan- 2-one top
Crystal data top
C20H34O2SiF(000) = 1472
Mr = 334.56Dx = 1.136 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 20 reflections
a = 13.7374 (13) Åθ = 14–17.7°
b = 14.7647 (11) ŵ = 0.13 mm1
c = 19.2829 (12) ÅT = 223 K
V = 3911.1 (5) Å3Block, colourless
Z = 80.53 × 0.42 × 0.34 mm
Data collection top
Stoe AED2 four-circle
diffractometer
Rint = 0.042
Radiation source: fine-focus sealed tubeθmax = 25.5°, θmin = 2.1°
Graphite monochromatorh = 1616
2θ/ω scansk = 017
7284 measured reflectionsl = 023
3642 independent reflections3 standard reflections every 60 min
2718 reflections with I > 2σ(I) intensity decay: <1%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.048H-atom parameters constrained
wR(F2) = 0.116 w = 1/[σ2(Fo2) + (0.0378P)2 + 2.3403P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max < 0.001
3642 reflectionsΔρmax = 0.28 e Å3
216 parametersΔρmin = 0.29 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0018 (5)
Crystal data top
C20H34O2SiV = 3911.1 (5) Å3
Mr = 334.56Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 13.7374 (13) ŵ = 0.13 mm1
b = 14.7647 (11) ÅT = 223 K
c = 19.2829 (12) Å0.53 × 0.42 × 0.34 mm
Data collection top
Stoe AED2 four-circle
diffractometer
Rint = 0.042
7284 measured reflections3 standard reflections every 60 min
3642 independent reflections intensity decay: <1%
2718 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.116H-atom parameters constrained
S = 1.07Δρmax = 0.28 e Å3
3642 reflectionsΔρmin = 0.29 e Å3
216 parameters
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
Si10.18635 (4)0.81357 (4)0.04887 (3)0.0263 (2)
O20.27615 (14)0.95616 (16)0.38174 (11)0.0711 (8)
O70.17598 (10)0.86338 (10)0.12503 (7)0.0312 (5)
C10.21973 (17)0.97101 (17)0.26241 (13)0.0408 (8)
C20.21585 (18)0.93807 (18)0.33818 (13)0.0454 (9)
C30.12597 (18)0.87879 (17)0.35050 (12)0.0401 (8)
C40.09843 (16)0.84971 (14)0.27688 (11)0.0301 (7)
C50.00409 (17)0.83122 (15)0.24976 (12)0.0350 (7)
C60.00658 (16)0.84850 (16)0.17076 (12)0.0355 (7)
C70.09821 (15)0.90983 (14)0.15884 (11)0.0274 (6)
C80.0748 (2)0.99911 (16)0.12245 (12)0.0427 (8)
C90.0247 (2)1.05514 (15)0.17828 (12)0.0457 (9)
C100.07572 (17)1.03098 (14)0.24635 (12)0.0346 (7)
C110.1814 (2)1.06806 (17)0.25435 (15)0.0527 (9)
C120.12488 (15)0.93286 (14)0.23397 (10)0.0264 (6)
C130.16461 (18)0.76782 (15)0.25992 (13)0.0403 (8)
C140.0109 (2)1.05498 (16)0.30795 (13)0.0445 (8)
C150.15738 (19)0.68993 (15)0.05640 (13)0.0419 (8)
C160.10610 (18)0.86511 (17)0.01811 (12)0.0418 (8)
C170.31834 (16)0.82806 (16)0.02537 (12)0.0340 (7)
C180.3464 (2)0.92884 (18)0.02703 (16)0.0554 (10)
C190.38166 (19)0.7765 (2)0.07777 (15)0.0543 (10)
C200.3373 (2)0.7910 (2)0.04778 (14)0.0584 (10)
H10.279500.955900.236200.0490*
H3A0.141700.826300.379600.0480*
H3B0.073400.913400.372400.0480*
H5A0.051600.872700.270600.0420*
H5B0.023900.768700.259100.0420*
H6A0.051800.878700.152900.0430*
H6B0.014400.790900.146200.0430*
H8A0.134301.028900.106300.0510*
H8B0.031400.989200.082800.0510*
H9A0.044701.040200.180700.0550*
H9B0.031401.120000.168400.0550*
H11A0.205801.099000.212900.0630*
H11B0.190701.105600.295700.0630*
H13A0.232300.785300.265200.0600*
H13B0.153100.748500.212500.0600*
H13C0.149900.718400.291400.0600*
H14A0.047701.048600.350600.0670*
H14B0.044701.014600.309000.0670*
H14C0.011401.117000.303400.0670*
H15A0.191400.664700.096000.0630*
H15B0.177900.658900.014500.0630*
H15C0.087800.682200.062600.0630*
H16A0.039000.862900.002500.0630*
H16B0.112400.831700.061200.0630*
H16C0.125100.927600.025600.0630*
H18A0.306400.962000.005700.0830*
H18B0.414400.935400.014600.0830*
H18C0.336000.952700.073300.0830*
H19A0.367300.797700.124300.0810*
H19B0.449900.787000.067500.0810*
H19C0.367800.712200.074600.0810*
H20A0.298600.824500.081100.0880*
H20B0.319600.727400.049500.0880*
H20C0.405800.797600.059000.0880*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Si10.0267 (3)0.0288 (3)0.0234 (3)0.0009 (3)0.0002 (2)0.0016 (2)
O20.0468 (12)0.1080 (18)0.0584 (13)0.0074 (12)0.0202 (10)0.0360 (12)
O70.0315 (8)0.0354 (8)0.0266 (8)0.0075 (7)0.0024 (6)0.0031 (6)
C10.0288 (12)0.0511 (15)0.0425 (14)0.0097 (11)0.0079 (10)0.0142 (12)
C20.0339 (13)0.0608 (17)0.0415 (14)0.0103 (12)0.0048 (11)0.0216 (13)
C30.0426 (14)0.0460 (14)0.0318 (13)0.0112 (12)0.0006 (11)0.0006 (11)
C40.0323 (12)0.0287 (11)0.0292 (11)0.0019 (10)0.0013 (9)0.0004 (9)
C50.0323 (12)0.0314 (12)0.0414 (12)0.0064 (10)0.0077 (10)0.0011 (10)
C60.0271 (12)0.0399 (13)0.0394 (13)0.0012 (10)0.0039 (10)0.0063 (11)
C70.0284 (11)0.0281 (11)0.0256 (11)0.0048 (9)0.0022 (9)0.0019 (9)
C80.0627 (17)0.0343 (13)0.0310 (12)0.0148 (12)0.0064 (12)0.0048 (10)
C90.0645 (17)0.0298 (13)0.0429 (14)0.0164 (12)0.0083 (13)0.0055 (11)
C100.0435 (14)0.0248 (11)0.0355 (12)0.0003 (10)0.0094 (11)0.0008 (10)
C110.0632 (18)0.0436 (14)0.0512 (15)0.0225 (14)0.0151 (14)0.0114 (13)
C120.0238 (10)0.0266 (10)0.0287 (11)0.0010 (9)0.0032 (9)0.0028 (9)
C130.0480 (15)0.0355 (13)0.0375 (14)0.0132 (11)0.0011 (11)0.0034 (11)
C140.0577 (16)0.0332 (13)0.0427 (14)0.0102 (12)0.0110 (13)0.0047 (11)
C150.0503 (15)0.0333 (12)0.0421 (14)0.0037 (11)0.0075 (12)0.0053 (11)
C160.0405 (14)0.0484 (15)0.0365 (13)0.0056 (12)0.0095 (11)0.0016 (11)
C170.0288 (11)0.0417 (13)0.0314 (11)0.0007 (10)0.0003 (10)0.0056 (10)
C180.0435 (15)0.0518 (17)0.0710 (19)0.0147 (13)0.0071 (14)0.0009 (15)
C190.0355 (14)0.0663 (19)0.0610 (17)0.0126 (13)0.0082 (13)0.0025 (15)
C200.0459 (16)0.085 (2)0.0443 (15)0.0068 (14)0.0161 (13)0.0147 (15)
Geometric parameters (Å, º) top
Si1—O71.6486 (15)C5—H5B0.9800
Si1—C151.874 (2)C6—H6A0.9800
Si1—C161.861 (2)C6—H6B0.9800
Si1—C171.881 (2)C8—H8A0.9800
O2—C21.210 (3)C8—H8B0.9800
O7—C71.427 (3)C9—H9A0.9800
C1—C21.541 (4)C9—H9B0.9800
C1—C111.535 (4)C11—H11A0.9800
C1—C121.522 (3)C11—H11B0.9800
C2—C31.532 (4)C13—H13A0.9700
C3—C41.531 (3)C13—H13B0.9700
C4—C51.527 (3)C13—H13C0.9700
C4—C121.524 (3)C14—H14A0.9700
C4—C131.548 (3)C14—H14B0.9700
C5—C61.552 (3)C14—H14C0.9700
C6—C71.568 (3)C15—H15A0.9700
C7—C81.528 (3)C15—H15B0.9700
C7—C121.533 (3)C15—H15C0.9700
C8—C91.522 (3)C16—H16A0.9700
C9—C101.530 (3)C16—H16B0.9700
C10—C111.559 (4)C16—H16C0.9700
C10—C121.616 (3)C18—H18A0.9700
C10—C141.526 (3)C18—H18B0.9700
C17—C181.537 (4)C18—H18C0.9700
C17—C191.535 (4)C19—H19A0.9700
C17—C201.535 (4)C19—H19B0.9700
C1—H10.9900C19—H19C0.9700
C3—H3A0.9800C20—H20A0.9700
C3—H3B0.9800C20—H20B0.9700
C5—H5A0.9800C20—H20C0.9700
O7—Si1—C15110.32 (10)C5—C6—H6A110.00
O7—Si1—C16112.62 (9)C5—C6—H6B110.00
O7—Si1—C17104.31 (9)C7—C6—H6A110.00
C15—Si1—C16109.05 (11)C7—C6—H6B110.00
C15—Si1—C17109.52 (11)H6A—C6—H6B108.00
C16—Si1—C17110.94 (11)C7—C8—H8A111.00
Si1—O7—C7133.31 (13)C7—C8—H8B111.00
C2—C1—C11112.3 (2)C9—C8—H8A111.00
C2—C1—C12101.26 (18)C9—C8—H8B111.00
C11—C1—C1290.88 (18)H8A—C8—H8B109.00
O2—C2—C1124.4 (2)C8—C9—H9A111.00
O2—C2—C3124.8 (2)C8—C9—H9B111.00
C1—C2—C3110.8 (2)C10—C9—H9A111.00
C2—C3—C4102.45 (18)C10—C9—H9B111.00
C3—C4—C5126.57 (19)H9A—C9—H9B109.00
C3—C4—C12102.63 (17)C1—C11—H11A114.00
C3—C4—C13105.66 (18)C1—C11—H11B114.00
C5—C4—C12100.25 (17)C10—C11—H11A114.00
C5—C4—C13109.25 (18)C10—C11—H11B114.00
C12—C4—C13111.99 (18)H11A—C11—H11B111.00
C4—C5—C6102.69 (18)C4—C13—H13A109.00
C5—C6—C7108.35 (18)C4—C13—H13B109.00
O7—C7—C6112.99 (17)C4—C13—H13C109.00
O7—C7—C8111.25 (17)H13A—C13—H13B109.00
O7—C7—C12111.07 (16)H13A—C13—H13C110.00
C6—C7—C8113.38 (18)H13B—C13—H13C110.00
C6—C7—C12100.46 (17)C10—C14—H14A109.00
C8—C7—C12107.04 (17)C10—C14—H14B109.00
C7—C8—C9103.85 (18)C10—C14—H14C109.00
C8—C9—C10105.8 (2)H14A—C14—H14B109.00
C9—C10—C11115.4 (2)H14A—C14—H14C109.00
C9—C10—C12105.88 (17)H14B—C14—H14C110.00
C9—C10—C14110.3 (2)Si1—C15—H15A109.00
C11—C10—C1286.58 (16)Si1—C15—H15B109.00
C11—C10—C14112.6 (2)Si1—C15—H15C109.00
C12—C10—C14124.53 (18)H15A—C15—H15B110.00
C1—C11—C1090.09 (18)H15A—C15—H15C109.00
C1—C12—C4107.85 (17)H15B—C15—H15C109.00
C1—C12—C7128.87 (18)Si1—C16—H16A109.00
C1—C12—C1088.44 (16)Si1—C16—H16B109.00
C4—C12—C7106.11 (17)Si1—C16—H16C109.00
C4—C12—C10122.83 (17)H16A—C16—H16B109.00
C7—C12—C10103.81 (16)H16A—C16—H16C110.00
Si1—C17—C18110.29 (16)H16B—C16—H16C109.00
Si1—C17—C19109.34 (16)C17—C18—H18A109.00
Si1—C17—C20110.14 (16)C17—C18—H18B109.00
C18—C17—C19108.9 (2)C17—C18—H18C109.00
C18—C17—C20108.8 (2)H18A—C18—H18B110.00
C19—C17—C20109.4 (2)H18A—C18—H18C109.00
C2—C1—H1116.00H18B—C18—H18C109.00
C11—C1—H1116.00C17—C19—H19A109.00
C12—C1—H1116.00C17—C19—H19B109.00
C2—C3—H3A111.00C17—C19—H19C109.00
C2—C3—H3B111.00H19A—C19—H19B109.00
C4—C3—H3A111.00H19A—C19—H19C110.00
C4—C3—H3B111.00H19B—C19—H19C109.00
H3A—C3—H3B109.00C17—C20—H20A110.00
C4—C5—H5A111.00C17—C20—H20B109.00
C4—C5—H5B111.00C17—C20—H20C109.00
C6—C5—H5A111.00H20A—C20—H20B109.00
C6—C5—H5B111.00H20A—C20—H20C109.00
H5A—C5—H5B109.00H20B—C20—H20C109.00
C15—Si1—O7—C792.99 (19)C5—C4—C12—C1170.87 (17)
C16—Si1—O7—C729.1 (2)C5—C4—C12—C747.9 (2)
C17—Si1—O7—C7149.49 (18)C5—C4—C12—C1070.9 (2)
O7—Si1—C17—C1855.54 (19)C13—C4—C12—C173.4 (2)
O7—Si1—C17—C1964.20 (18)C13—C4—C12—C767.8 (2)
O7—Si1—C17—C20175.58 (16)C13—C4—C12—C10173.39 (19)
C15—Si1—C17—C18173.61 (17)C4—C5—C6—C721.3 (2)
C15—Si1—C17—C1953.9 (2)C5—C6—C7—O7111.29 (19)
C15—Si1—C17—C2066.4 (2)C5—C6—C7—C8121.0 (2)
C16—Si1—C17—C1866.0 (2)C5—C6—C7—C127.1 (2)
C16—Si1—C17—C19174.29 (17)O7—C7—C8—C9157.49 (18)
C16—Si1—C17—C2054.1 (2)C6—C7—C8—C973.9 (2)
Si1—O7—C7—C660.9 (2)C12—C7—C8—C936.0 (2)
Si1—O7—C7—C867.9 (2)O7—C7—C12—C143.8 (3)
Si1—O7—C7—C12172.93 (14)O7—C7—C12—C486.14 (19)
C11—C1—C2—O281.3 (3)O7—C7—C12—C10143.17 (16)
C11—C1—C2—C399.2 (2)C6—C7—C12—C1163.6 (2)
C12—C1—C2—O2177.0 (3)C6—C7—C12—C433.6 (2)
C12—C1—C2—C33.5 (3)C6—C7—C12—C1097.06 (18)
C2—C1—C11—C1086.9 (2)C8—C7—C12—C177.8 (3)
C12—C1—C11—C1015.64 (18)C8—C7—C12—C4152.24 (18)
C2—C1—C12—C426.3 (2)C8—C7—C12—C1021.5 (2)
C2—C1—C12—C7155.6 (2)C7—C8—C9—C1035.9 (2)
C2—C1—C12—C1097.84 (18)C8—C9—C10—C1171.4 (2)
C11—C1—C12—C4139.21 (19)C8—C9—C10—C1222.4 (2)
C11—C1—C12—C791.5 (2)C8—C9—C10—C14159.60 (19)
C11—C1—C12—C1015.08 (18)C9—C10—C11—C1120.7 (2)
O2—C2—C3—C4159.7 (3)C12—C10—C11—C114.73 (17)
C1—C2—C3—C419.8 (3)C14—C10—C11—C1111.5 (2)
C2—C3—C4—C5147.8 (2)C9—C10—C12—C1130.35 (19)
C2—C3—C4—C1234.7 (2)C9—C10—C12—C4119.3 (2)
C2—C3—C4—C1382.8 (2)C9—C10—C12—C70.6 (2)
C3—C4—C5—C6155.0 (2)C11—C10—C12—C114.86 (18)
C12—C4—C5—C640.8 (2)C11—C10—C12—C4125.2 (2)
C13—C4—C5—C677.0 (2)C11—C10—C12—C7114.91 (18)
C3—C4—C12—C139.5 (2)C14—C10—C12—C1100.4 (2)
C3—C4—C12—C7179.32 (17)C14—C10—C12—C49.9 (3)
C3—C4—C12—C1060.5 (2)C14—C10—C12—C7129.8 (2)

Experimental details

Crystal data
Chemical formulaC20H34O2Si
Mr334.56
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)223
a, b, c (Å)13.7374 (13), 14.7647 (11), 19.2829 (12)
V3)3911.1 (5)
Z8
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.53 × 0.42 × 0.34
Data collection
DiffractometerStoe AED2 four-circle
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
7284, 3642, 2718
Rint0.042
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.116, 1.07
No. of reflections3642
No. of parameters216
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.28, 0.29

Computer programs: STADI-4 (Stoe & Cie, 1997), X-RED (Stoe & Cie, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).

 

Acknowledgements

This work was supported financially by the Swiss National Science Foundation.

References

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