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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

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

aState Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
*Correspondence e-mail: xiaaibao@zjut.edu.cn

(Received 27 December 2012; accepted 15 January 2013; online 19 January 2013)

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[Hayashi, Y., Gotog, H., Hayashi, T. & Shoji, M. (2005). Angew. Chem. Int. Ed. 44, 4212-4215.]); Li et al. (2009[Li, Z., Guo, Y., Li, B. & Luo, S. (2009). Acta Cryst. E65, o2023.]); Xia et al. (2009[Xia, A.-B., Tang, J., Jiang, J.-R., Wang, Y.-F. & Luo, S.-P. (2009). Acta Cryst. E65, o2091.]); Wu et al. (2011[Wu, C., Zhao, L. & Xia, A.-B. (2011). Acta Cryst. E67, o1939.]). For asymmetric Michael addition reactions, see: Luo et al. (2007[Luo, S., Zhang, L., Mi, X., Qiao, Y. & Cheng, J.-P. (2007). J. Org. Chem. 72, 9350-9352.]). For enanti­oselective organocatalytic Michael additions, see: Peelen et al. (2005[Peelen, T. J., Chi, Y. & Gellman, S. H. (2005). J. Am. Chem. Soc. 127, 11598-11599.]); Ma et al. (2008[Ma, A., Zhu, S. & Ma, D. (2008). Tetrahedron Lett. 49, 3075-3077.]).

[Scheme 1]

Experimental

Crystal data
  • C16H20BrNO3

  • Mr = 354.24

  • Monoclinic, P 21

  • 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[Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.279, Tmax = 0.644

  • 7234 measured reflections

  • 3277 independent reflections

  • 1619 reflections with I > 2σ(I)

  • Rint = 0.071

Refinement
  • R[F2 > 2σ(F2)] = 0.056

  • wR(F2) = 0.175

  • S = 1.00

  • 3277 reflections

  • 191 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.35 e Å−3

  • Δρmin = −0.29 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 1259 Friedel pairs

  • Flack parameter: 0.03 (2)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA 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
Symmetry code: (i) x+1, y, z.

Data collection: PROCESS-AUTO (Rigaku, 2006[Rigaku (2006). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan.]); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku, 2007[Rigaku (2007). CrystalStructure. Rigaku Americas, The Woodlands, Texas, USA.]); 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: ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]); software used to prepare material for publication: WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).

Supporting information


Comment top

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).

Related literature top

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 top

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.

Refinement top

H atoms were placed in calculated position with C—H ranging from 0.93 Å to 0.98 Å. All H atoms were included in the final cycles of refinement as riding mode, with Uiso(H) = 1.2Ueq(C) for aromatic, methylene and methine H atoms, and with Uiso(H) = 1.5Ueq(C) for methyl H atoms.

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 2006); cell refinement: PROCESS-AUTO (Rigaku, 2006); 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).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atomic labeling scheme. Displacement ellipsoids are drawn at the 50% probability level.
(2S,4R)-2-[(1R)-1-(4-Bromophenyl)-2-nitroethyl]- 4-ethylcyclohexanone top
Crystal data top
C16H20BrNO3F(000) = 364
Mr = 354.24Dx = 1.396 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 4682 reflections
a = 5.6434 (4) Åθ = 3.4–27.4°
b = 9.2179 (6) ŵ = 2.45 mm1
c = 16.5472 (9) ÅT = 296 K
β = 101.782 (3)°Platelet, colourless
V = 842.65 (9) Å30.52 × 0.31 × 0.18 mm
Z = 2
Data collection top
Rigaku R-AXIS RAPID/ZJUG
diffractometer
3277 independent reflections
Radiation source: rotating anode1619 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.071
Detector resolution: 10.00 pixels mm-1θmax = 26.0°, θmin = 3.4°
ω scansh = 66
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
k = 1111
Tmin = 0.279, Tmax = 0.644l = 2020
7234 measured reflections
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.056 w = 1/[σ2(Fo2) + (0.0605P)2 + 0.3P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.175(Δ/σ)max < 0.001
S = 1.00Δρmax = 0.35 e Å3
3277 reflectionsΔρmin = 0.29 e Å3
191 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraintExtinction coefficient: 0.072 (8)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 1259 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.03 (2)
Crystal data top
C16H20BrNO3V = 842.65 (9) Å3
Mr = 354.24Z = 2
Monoclinic, P21Mo Kα radiation
a = 5.6434 (4) ŵ = 2.45 mm1
b = 9.2179 (6) ÅT = 296 K
c = 16.5472 (9) Å0.52 × 0.31 × 0.18 mm
β = 101.782 (3)°
Data collection top
Rigaku R-AXIS RAPID/ZJUG
diffractometer
3277 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
1619 reflections with I > 2σ(I)
Tmin = 0.279, Tmax = 0.644Rint = 0.071
7234 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.056H-atom parameters constrained
wR(F2) = 0.175Δρmax = 0.35 e Å3
S = 1.00Δρmin = 0.29 e Å3
3277 reflectionsAbsolute structure: Flack (1983), 1259 Friedel pairs
191 parametersAbsolute structure parameter: 0.03 (2)
1 restraint
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
C10.2312 (11)0.2884 (7)0.1770 (4)0.0563 (15)
H10.07660.33790.17540.068*
C20.4174 (11)0.4066 (6)0.1660 (4)0.0541 (15)
H20.54990.35920.14610.065*
C30.3093 (14)0.5225 (7)0.1030 (4)0.0712 (19)
C40.4813 (15)0.6373 (10)0.0880 (5)0.091 (3)
H4A0.39570.70960.05040.109*
H4B0.60600.59480.06290.109*
C50.5974 (14)0.7093 (9)0.1702 (5)0.090 (2)
H5A0.71900.77780.16050.108*
H5B0.47420.76340.19050.108*
C60.7146 (11)0.6025 (7)0.2361 (5)0.0672 (18)
H60.84460.55330.21560.081*
C70.5264 (10)0.4859 (8)0.2467 (3)0.0582 (14)
H7A0.60310.41530.28720.070*
H7B0.39690.53170.26790.070*
C80.8263 (14)0.6704 (9)0.3179 (5)0.089 (2)
H8A0.88670.59340.35650.107*
H8B0.69990.72060.33870.107*
C91.0317 (16)0.7769 (10)0.3167 (7)0.110 (3)
H9A1.09040.81370.37140.165*
H9B0.97360.85580.28020.165*
H9C1.16070.72820.29780.165*
C100.2948 (10)0.2114 (7)0.2592 (4)0.0522 (14)
C110.4955 (12)0.1193 (7)0.2768 (4)0.0646 (17)
H110.58750.10420.23690.078*
C120.5606 (13)0.0500 (7)0.3524 (5)0.075 (2)
H120.69650.00940.36370.090*
C130.4189 (15)0.0708 (8)0.4112 (5)0.076 (2)
C140.2187 (14)0.1583 (8)0.3947 (4)0.0708 (19)
H140.12440.17140.43410.085*
C150.1579 (11)0.2267 (8)0.3194 (4)0.0622 (17)
H150.02060.28510.30850.075*
C160.1937 (11)0.1852 (7)0.1032 (4)0.0616 (17)
H16A0.13940.23990.05270.074*
H16B0.34640.13950.10010.074*
N10.0135 (12)0.0724 (7)0.1101 (4)0.0700 (16)
O10.0953 (10)0.5240 (6)0.0704 (3)0.0925 (19)
O20.0723 (11)0.0541 (7)0.1111 (4)0.1028 (18)
O30.1912 (9)0.1117 (7)0.1163 (3)0.0939 (17)
Br10.5073 (2)0.02467 (17)0.51442 (5)0.1269 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.058 (3)0.059 (3)0.054 (4)0.002 (3)0.015 (3)0.004 (3)
C20.053 (3)0.055 (3)0.056 (3)0.005 (3)0.015 (3)0.006 (3)
C30.089 (5)0.074 (5)0.053 (4)0.003 (4)0.019 (3)0.010 (3)
C40.096 (5)0.099 (6)0.074 (5)0.021 (5)0.007 (4)0.028 (4)
C50.084 (5)0.071 (5)0.120 (7)0.004 (4)0.028 (5)0.035 (5)
C60.058 (4)0.052 (4)0.091 (5)0.004 (3)0.012 (4)0.001 (4)
C70.063 (3)0.050 (3)0.059 (3)0.002 (3)0.008 (3)0.005 (4)
C80.084 (5)0.076 (5)0.105 (6)0.013 (4)0.013 (4)0.015 (4)
C90.087 (5)0.092 (6)0.153 (10)0.022 (5)0.030 (6)0.035 (6)
C100.050 (3)0.050 (3)0.056 (4)0.002 (3)0.009 (3)0.005 (3)
C110.072 (4)0.067 (4)0.059 (4)0.004 (4)0.023 (3)0.010 (3)
C120.069 (4)0.061 (4)0.089 (5)0.005 (3)0.000 (4)0.002 (4)
C130.094 (5)0.069 (4)0.063 (4)0.006 (4)0.011 (4)0.015 (4)
C140.085 (5)0.083 (5)0.047 (4)0.001 (4)0.020 (3)0.003 (3)
C150.062 (4)0.066 (4)0.062 (4)0.001 (4)0.019 (3)0.002 (3)
C160.060 (3)0.074 (5)0.051 (3)0.011 (3)0.012 (3)0.008 (4)
N10.077 (4)0.078 (5)0.053 (3)0.015 (4)0.009 (3)0.001 (3)
O10.081 (3)0.111 (5)0.077 (3)0.000 (3)0.003 (3)0.031 (3)
O20.107 (4)0.067 (4)0.128 (5)0.012 (3)0.007 (3)0.016 (3)
O30.063 (3)0.127 (5)0.097 (4)0.028 (3)0.030 (3)0.031 (3)
Br10.1788 (11)0.1258 (9)0.0677 (6)0.0169 (8)0.0050 (5)0.0258 (7)
Geometric parameters (Å, º) top
C1—C101.511 (8)C8—H8A0.9700
C1—C161.528 (8)C8—H8B0.9700
C1—C21.550 (8)C9—H9A0.9600
C1—H10.9800C9—H9B0.9600
C2—C31.530 (8)C9—H9C0.9600
C2—C71.535 (8)C10—C151.387 (8)
C2—H20.9800C10—C111.398 (8)
C3—O11.218 (8)C11—C121.386 (9)
C3—C41.490 (10)C11—H110.9300
C4—C51.536 (12)C12—C131.392 (11)
C4—H4A0.9700C12—H120.9300
C4—H4B0.9700C13—C141.370 (10)
C5—C61.517 (10)C13—Br11.896 (8)
C5—H5A0.9700C14—C151.376 (9)
C5—H5B0.9700C14—H140.9300
C6—C81.506 (10)C15—H150.9300
C6—C71.546 (9)C16—N11.475 (9)
C6—H60.9800C16—H16A0.9700
C7—H7A0.9700C16—H16B0.9700
C7—H7B0.9700N1—O21.212 (9)
C8—C91.522 (11)N1—O31.235 (7)
C10—C1—C16113.3 (5)C6—C8—C9115.9 (8)
C10—C1—C2113.2 (5)C6—C8—H8A108.3
C16—C1—C2109.3 (5)C9—C8—H8A108.3
C10—C1—H1106.9C6—C8—H8B108.3
C16—C1—H1106.9C9—C8—H8B108.3
C2—C1—H1106.9H8A—C8—H8B107.4
C3—C2—C7107.1 (5)C8—C9—H9A109.5
C3—C2—C1112.7 (5)C8—C9—H9B109.5
C7—C2—C1113.2 (5)H9A—C9—H9B109.5
C3—C2—H2107.9C8—C9—H9C109.5
C7—C2—H2107.9H9A—C9—H9C109.5
C1—C2—H2107.9H9B—C9—H9C109.5
O1—C3—C4122.6 (6)C15—C10—C11117.3 (6)
O1—C3—C2122.0 (6)C15—C10—C1122.3 (5)
C4—C3—C2115.3 (6)C11—C10—C1120.4 (5)
C3—C4—C5109.5 (6)C12—C11—C10121.5 (6)
C3—C4—H4A109.8C12—C11—H11119.2
C5—C4—H4A109.8C10—C11—H11119.2
C3—C4—H4B109.8C11—C12—C13118.9 (7)
C5—C4—H4B109.8C11—C12—H12120.6
H4A—C4—H4B108.2C13—C12—H12120.6
C6—C5—C4113.7 (7)C14—C13—C12120.7 (7)
C6—C5—H5A108.8C14—C13—Br1120.5 (6)
C4—C5—H5A108.8C12—C13—Br1118.8 (6)
C6—C5—H5B108.8C15—C14—C13119.6 (7)
C4—C5—H5B108.8C15—C14—H14120.2
H5A—C5—H5B107.7C13—C14—H14120.2
C8—C6—C5114.6 (6)C14—C15—C10122.1 (6)
C8—C6—C7111.0 (6)C14—C15—H15119.0
C5—C6—C7108.9 (5)C10—C15—H15119.0
C8—C6—H6107.3N1—C16—C1111.2 (5)
C5—C6—H6107.3N1—C16—H16A109.4
C7—C6—H6107.3C1—C16—H16A109.4
C2—C7—C6113.3 (5)N1—C16—H16B109.4
C2—C7—H7A108.9C1—C16—H16B109.4
C6—C7—H7A108.9H16A—C16—H16B108.0
C2—C7—H7B108.9O2—N1—O3122.6 (7)
C6—C7—H7B108.9O2—N1—C16119.2 (7)
H7A—C7—H7B107.7O3—N1—C16118.1 (6)
C10—C1—C2—C3156.6 (5)C16—C1—C10—C15122.7 (7)
C16—C1—C2—C376.1 (6)C2—C1—C10—C15112.1 (7)
C10—C1—C2—C734.9 (7)C16—C1—C10—C1156.5 (8)
C16—C1—C2—C7162.2 (5)C2—C1—C10—C1168.7 (8)
C7—C2—C3—O1120.3 (7)C15—C10—C11—C122.2 (9)
C1—C2—C3—O14.8 (9)C1—C10—C11—C12178.6 (6)
C7—C2—C3—C456.5 (8)C10—C11—C12—C131.3 (10)
C1—C2—C3—C4178.4 (6)C11—C12—C13—C140.0 (11)
O1—C3—C4—C5121.3 (8)C11—C12—C13—Br1179.8 (5)
C2—C3—C4—C555.4 (9)C12—C13—C14—C150.3 (11)
C3—C4—C5—C653.7 (9)Br1—C13—C14—C15179.9 (6)
C4—C5—C6—C8179.0 (6)C13—C14—C15—C100.7 (11)
C4—C5—C6—C754.0 (8)C11—C10—C15—C141.9 (10)
C3—C2—C7—C656.0 (7)C1—C10—C15—C14178.9 (6)
C1—C2—C7—C6179.2 (5)C10—C1—C16—N154.0 (7)
C8—C6—C7—C2176.6 (5)C2—C1—C16—N1178.8 (5)
C5—C6—C7—C256.3 (8)C1—C16—N1—O2120.9 (8)
C5—C6—C8—C961.7 (9)C1—C16—N1—O357.6 (7)
C7—C6—C8—C9174.4 (7)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···O3i0.932.563.478 (9)169
C16—H16B···O3i0.972.583.500 (8)158
Symmetry code: (i) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC16H20BrNO3
Mr354.24
Crystal system, space groupMonoclinic, P21
Temperature (K)296
a, b, c (Å)5.6434 (4), 9.2179 (6), 16.5472 (9)
β (°) 101.782 (3)
V3)842.65 (9)
Z2
Radiation typeMo Kα
µ (mm1)2.45
Crystal size (mm)0.52 × 0.31 × 0.18
Data collection
DiffractometerRigaku R-AXIS RAPID/ZJUG
diffractometer
Absorption correctionMulti-scan
(ABSCOR; Higashi, 1995)
Tmin, Tmax0.279, 0.644
No. of measured, independent and
observed [I > 2σ(I)] reflections
7234, 3277, 1619
Rint0.071
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.175, 1.00
No. of reflections3277
No. of parameters191
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.35, 0.29
Absolute structureFlack (1983), 1259 Friedel pairs
Absolute structure parameter0.03 (2)

Computer programs: PROCESS-AUTO (Rigaku, 2006), CrystalStructure (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), WinGX (Farrugia, 2012).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···O3i0.932.563.478 (9)168.7
C16—H16B···O3i0.972.583.500 (8)158.2
Symmetry code: (i) x+1, y, z.
 

Acknowledgements

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

References

First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals
First citationHayashi, Y., Gotog, H., Hayashi, T. & Shoji, M. (2005). Angew. Chem. Int. Ed. 44, 4212–4215.  Web of Science CrossRef CAS
First citationHigashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.
First citationLi, Z., Guo, Y., Li, B. & Luo, S. (2009). Acta Cryst. E65, o2023.  Web of Science CSD CrossRef IUCr Journals
First citationLuo, S., Zhang, L., Mi, X., Qiao, Y. & Cheng, J.-P. (2007). J. Org. Chem. 72, 9350–9352.  Web of Science CSD CrossRef PubMed CAS
First citationMa, A., Zhu, S. & Ma, D. (2008). Tetrahedron Lett. 49, 3075–3077.  Web of Science CrossRef CAS
First citationPeelen, T. J., Chi, Y. & Gellman, S. H. (2005). J. Am. Chem. Soc. 127, 11598–11599.  Web of Science CrossRef PubMed CAS
First citationRigaku (2006). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan.
First citationRigaku (2007). CrystalStructure. Rigaku Americas, The Woodlands, Texas, USA.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationWu, C., Zhao, L. & Xia, A.-B. (2011). Acta Cryst. E67, o1939.  Web of Science CSD CrossRef IUCr Journals
First citationXia, A.-B., Tang, J., Jiang, J.-R., Wang, Y.-F. & Luo, S.-P. (2009). Acta Cryst. E65, o2091.  Web of Science CSD CrossRef IUCr Journals

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds