(S)-4-(2-Chloro­propan-2-yl)-1-(2,2,2-trichloro­eth­yl)cyclo­hexene

Brahim Boualy; Mohamed Anoir Harrad; Larbi El Firdoussi; Mustapha Ait Ali; Corrado Rizzoli

doi:10.1107/S1600536811010257

. 2011 Mar 23;67(Pt 4):o960. doi: 10.1107/S1600536811010257

(S)-4-(2-Chloropropan-2-yl)-1-(2,2,2-trichloroethyl)cyclohexene

Brahim Boualy ^a, Mohamed Anoir Harrad ^a, Larbi El Firdoussi ^a, Mustapha Ait Ali ^a, Corrado Rizzoli ^b,^*

PMCID: PMC3100074 PMID: 21754224

Abstract

The title compound, C₁₁H₁₆Cl₄, was synthesized by the reaction of (1S)-β-pinene with triethylamine in the presence of ZnCl₂. The cyclohexene ring assumes a half-boat conformation. The crystal packing is governed only by van der Waals interactions. The structure, which has been refined in P2₁, presents a striking P2₁/m pseudosymmetry.

Related literature

For background to the synthesis of polyhalogenated compounds, see: Delaude et al. (2004 ▶); Borguet et al. (2007 ▶). For the synthesis and structure of natural chlorinated compounds reported by our group, see: Ziyat et al. (2002 ▶, 2004 ▶); Boualy et al. (2009 ▶). For bond-length data, see: Allen et al. (1987 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₁H₁₆Cl₄
M _r = 290.04
Monoclinic,
a = 10.6558 (7) Å
b = 10.3017 (6) Å
c = 6.3119 (3) Å
β = 91.251 (5)°
V = 692.71 (7) Å³
Z = 2
Cu Kα radiation
μ = 7.50 mm⁻¹
T = 294 K
0.21 × 0.09 × 0.07 mm

Data collection

Siemens AED diffractometer
Absorption correction: refined from ΔF (DIFABS; Walker & Stuart, 1983 ▶) T _min = 0.456, T _max = 0.601
2764 measured reflections
2528 independent reflections
2206 reflections with I > 2σ(I)
R _int = 0.038
3 standard reflections every 100 reflections intensity decay: 0.02%

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.129
S = 1.16
2528 reflections
136 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.22 e Å⁻³
Absolute structure: Flack (1983 ▶); 1188 Friedel pairs
Flack parameter: −0.04 (3)

Data collection: AED (Belletti et al., 1993 ▶); cell refinement: AED; data reduction: AED; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and SCHAKAL97 (Keller, 1997 ▶); software used to prepare material for publication: SHELXL97 and PARST95 (Nardelli, 1995 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811010257/bg2395sup1.cif

e-67-0o960-sup1.cif^{(15.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811010257/bg2395Isup2.hkl

e-67-0o960-Isup2.hkl^{(124.2KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

Financial support from the Universitá degli Studi di Parma is gratefully acknowledged.

supplementary crystallographic information

Comment

The research on polyhalogenated alkanes, lactams and lactones, which are versatile intermediates in the synthesis of natural products and bioactive molecules, has held the attention of chemists for many years (Delaude et al., 2004). Among others, the Kharasch reaction is an effective method for the formation of these polyhalogenated products. This process consists in the addition of a polyhalogenated alkane to an alkene and requires either a radical initiator or a transition metal catalyst (Borguet et al., 2007). In the course of our ongoing research program aimed at the synthesis of natural chlorinated compounds (Ziyat et al., 2002; Ziyat et al., 2004; Boualy et al., 2009), the title compound has been obtained and its crystal structure is reported herein.

In the molecule of the title compound (Fig. 1) all bond lengths (Allen et al., 1987) and angles are normal. The cyclohexene ring assumes a half-boat conformation, with puckering parameters Q, θ and φ of 0.493 (4) Å, 51.9 (4)° and -142.0 (6)°, respectively (Cremer & Pople, 1975). The crystal structure (Fig. 2) is stabilized only by van der Waals interactions. The shortest intermolecular Cl···Cl separation observed is 3.5306 (11) Å (Cl2···Cl4ⁱ; symmetry code: (i) 1 + x, y, -1 + z). The structure, which has been refined in P2₁, presents a striking P2₁/m pseudosymmetry (See refinement section for details).

Experimental

A mixture of (1S)-β-pinene (1 g, 7.34 mmol) and triethylamine (1 ml, 7.11 mmol) in carbon tetrachloride (15 ml) was added to a solution of ZnCl₂ in (1.1 g, 8.09 mmol) in water (15 ml) under stirring at room temperature. On completion of the reaction, the mixture was diluted with 25 ml of water, extracted with carbon tetrachloride (3 × 10 ml) and dried over Na₂SO₄. The title compound was isolated as a white powder by column chromatography on silica gel using n-hexane as eluent (yield 90%; m. p. = 48 °C), but colourless single crystals suitable for X-ray analysis were obtained by slow evaporation of a n-hexane solution. ¹H NMR (300 MHz, CDCl₃): δ p.p.m. 5.71 (m, 1H), 3.28 (s, 2H), 2.29 (m, 3H), 1.97 (m, 2H), 1.65 (m, 1H), 1.53 (s, 3H), 1.54 (s, 3H). ¹³C NMR (75 MHz, CDCl₃): δ p.p.m. 131.03 (C_q), 130.53 (CH═C), 99.06 (CCl₃), 73.09 (CCl), 62.02 (CH₂–CCl₃), 45.73 (CH), 30.61 (CH₂), 29.83 (CH₃), 29.76 (CH₃), 28.19 (CH₂), 24.56 (CH₂).