(2S,4R)-2-[(1R)-1-(4-Bromo­phen­yl)-2-nitro­eth­yl]-4-ethyl­cyclo­hexa­none

Chi-Xiao Zhang; Yan-Peng Zhang; Ai-Bao Xia

doi:10.1107/S1600536813001426

. 2013 Jan 19;69(Pt 2):o263. doi: 10.1107/S1600536813001426

(2S,4R)-2-[(1R)-1-(4-Bromophenyl)-2-nitroethyl]-4-ethylcyclohexanone

Chi-Xiao Zhang ^a, Yan-Peng Zhang ^a, Ai-Bao Xia ^a,^*

PMCID: PMC3569793 PMID: 23424539

Abstract

The crystal structure of the title compound, C₁₆H₂₀BrNO₃, contains three chiral centers in the configuration 1R,2S,6R. The cyclohexane ring is in a chair conformation. In the crystal, molecules are linked by weak C—H⋯O interactions, forming chains along the a-axis direction.

Related literature

For related compounds, see: Hayashi et al. (2005 ▶); Li et al. (2009 ▶); Xia et al. (2009 ▶); Wu et al. (2011 ▶). For asymmetric Michael addition reactions, see: Luo et al. (2007 ▶). For enantioselective organocatalytic Michael additions, see: Peelen et al. (2005 ▶); Ma et al. (2008 ▶).

Experimental

Crystal data

C₁₆H₂₀BrNO₃
M _r = 354.24
Monoclinic,
a = 5.6434 (4) Å
b = 9.2179 (6) Å
c = 16.5472 (9) Å
β = 101.782 (3)°
V = 842.65 (9) Å³
Z = 2
Mo Kα radiation
μ = 2.45 mm⁻¹
T = 296 K
0.52 × 0.31 × 0.18 mm

Data collection

Rigaku R-AXIS RAPID/ZJUG diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.279, T _max = 0.644
7234 measured reflections
3277 independent reflections
1619 reflections with I > 2σ(I)
R _int = 0.071

Refinement

R[F ² > 2σ(F ²)] = 0.056
wR(F ²) = 0.175
S = 1.00
3277 reflections
191 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.29 e Å⁻³
Absolute structure: Flack (1983 ▶), 1259 Friedel pairs
Flack parameter: 0.03 (2)

Data collection: PROCESS-AUTO (Rigaku, 2006 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku, 2007 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Supplementary Material

Click here for additional data file.^{(24.1KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813001426/zq2194sup1.cif

e-69-0o263-sup1.cif^{(24.1KB, cif)}

Click here for additional data file.^{(157.5KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813001426/zq2194Isup2.hkl

e-69-0o263-Isup2.hkl^{(157.5KB, hkl)}

Click here for additional data file.^{(6.1KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813001426/zq2194Isup3.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H11⋯O3ⁱ	0.93	2.56	3.478 (9)	169
C16—H16B⋯O3ⁱ	0.97	2.58	3.500 (8)	158

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank Professor Jian-Ming Gu of Zhejiang University for his help.

supplementary crystallographic information

Comment

The Michael reaction (e.g. Luo et al., 2007; Ma et al., 2008; Peelen et al., 2005) of a carbon nucleophile with a nitroalkene is one useful synthetic method for the preparation of nitroalkanes, which are versatile synthetic intermediates owing to the various possible transformations of the nitro group into other useful functional groups (Hayashi et al., 2005). The title compound was obtained from the Michael addition of 4-ethylcyclohexanone to 1-(4-bromophenyl)-2-nitroethene in our laboratory. For related structures, see: Li et al. (2009); Xia et al. (2009); Wu et al. (2011).

The title compound is shown in Fig. 1.The cyclohexyl ring adopts a chair conformation. The plane of the phenyl ring and the least-square plane of the cyclohexyl moiety enclose an angle of 70.00 (3)° while the plane through the nitro group and the adjacent C16 atom encloses an angle of 63.26 (3)° with the phenyl ring. In the crystal, molecules are linked by weak C—H···O interactions forming chains along the a axis (Table 1).

Experimental

An isopropyl ether (0.5 mL) solution of 1-(4-bromophenyl)-2-nitroethene (0.6 mmol) and 4-ethylcyclohexanone (1.2 mmol) was stirred with the (S)-2-(pyrrolidin-2-ylmethylthio)pyridine (0.12 mmol) as catalyst and benzoic acid (0.12 mmol) as cocatalyst at room temperature. After completion of the reaction, the mixture was extracted with ethyl acetate. Solvents were removed under vacuum and the residue was purified by column chromatography on silica gel (eluent: petroleum ether-ether). Suitable crystals were obtained by slow evaporation of an ether solution.