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

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ISSN: 2056-9890

(2R,4R)-2-Hydr­­oxy-4-(2-meth­oxy­phen­yl)bi­cyclo­[3.3.1]nonan-9-one

aState Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
*Correspondence e-mail: lsp96@163.com

(Received 3 July 2009; accepted 22 July 2009; online 29 July 2009)

The title compound, C16H20O3, contains a bicyclic ring system with two chiral centers. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds. The absolute configuration was established by the stereo-selectivity of the asymmetric organocatalysis.

Related literature

A similar structure is described by Cao et al. (2007[Cao, C., Sun, X., Kang, Y. & Tang, Y. (2007). Org. Lett. 9, 4151-4154.]). For general background to organocatalysis, see: List et al. (2000[List, B., Lerner, R. A. & Barbas, III (2000). J. Am. Chem. Soc. 122, 2395-2396.], 2001[List, B., Pojarliev, P. & Martin, H. J. (2001). Org. Lett. 3, 2423-2425.]); Notz et al. (2001[Notz, W., Sakthivel, K., Bui, T., Zhong, G. & Barbas, C. F. III (2001). Tetrahedron Lett. 42, 199-201.]).

[Scheme 1]

Experimental

Crystal data
  • C16H20O3

  • Mr = 260.33

  • Orthorhombic, P 21 21 21

  • a = 6.9378 (5) Å

  • b = 12.5291 (11) Å

  • c = 16.0726 (14) Å

  • V = 1397.1 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 296 K

  • 0.47 × 0.32 × 0.29 mm

Data collection
  • Rigaku R-AXIS RAPID diffractometer

  • Absorption correction: multi-scan (ABSCOR; Higashi, 1995[Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.945, Tmax = 0.976

  • 13314 measured reflections

  • 1840 independent reflections

  • 1211 reflections with F2 > 2σ(F2)

  • Rint = 0.034

Refinement
  • R[F2 > 2σ(F2)] = 0.032

  • wR(F2) = 0.061

  • S = 1.00

  • 1840 reflections

  • 173 parameters

  • H-atom parameters constrained

  • Δρmax = 0.16 e Å−3

  • Δρmin = −0.13 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H101⋯O2i 0.85 1.99 2.8268 (19) 171
O1ii—H101ii⋯O2 0.85 1.99 2.8268 (19) 171
C14—H14⋯O1iii 0.93 2.51 3.434 (2) 176
Symmetry codes: (i) [x+{\script{1\over 2}}, -y-{\script{1\over 2}}, -z]; (ii) [x-{\script{1\over 2}}, -y-{\script{1\over 2}}, -z]; (iii) [-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: PROCESS-AUTO (Rigaku, 2006[Rigaku (2006). PROCESS-AUTO Rigaku Corporation, Tokyo, Japan.]); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004[Rigaku/MSC (2004). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA.]), and Larson (1970[Larson, A. C. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, pp. 291-294. Copenhagen: Munksgaard.]); program(s) used to solve structure: SIR97 (Altomare et al., 1999[Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.]); program(s) used to refine structure: CRYSTALS (Watkin et al., 1996[Watkin, D. J., Prout, C. K., Carruthers, J. R. & Betteridge, P. W. (1996). CRYSTALS. Chemical Crystallography Laboratory, Oxford, England.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2004[Rigaku/MSC (2004). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA.]).

Supporting information


Comment top

The natural amino acid L-proline, pioneered by List and Barbas III and their co-workers, has been fully appreciated as an attractive enantioselective organocatalyst for direct asymmetric carbon-carbon and carbon-heteroatom bond-forming reactions, such as aldol (List et al., 2000), Mannich (List et al., 2001) and Michael (Notz et al., 2000) reactions. In our laboratory, a novel tandem Michael-aldol reaction of ketones with cinnamaldehyde derivatives catalyzed by L-proline was developed and a series of new products was obtained. The crystal structure of one of these, the title compound, is reported in this article.

In the crystal structure of the title compound (Fig. 1), both bicyclic six-membered rings display chair conformations in which atoms C1, C8, C4, C3 and atoms C4, C8, C7, C5 each lie in an approximate plane with the dihedral angle between them being 115.9 (0)°. C9 is located above the two planes with similar dihedral angles. The hydroxyl group and the phenyl group are located on different sides of the plane made up of atoms C1, C8, C4, C3. The hydroxyl group is in an axial position, the phenyl group in an equatorial position of the cyclohexanone ring.

Intermolecular O—H···O hydrogen bonds (Tab. 1) connect neighboring molecules with each other to form a one-dimensional chain that stretches along the direction of the a axis (Fig. 2). Via weak C—H···O hydrogen bonds (Tab. 1) molecules are linked along the b axis to form another one-dimensional chain.

Related literature top

A similar structure is described by Cao et al. (2007). For general background to organocatalysis, see: List et al. (2000, 2001); Notz et al. (2001).

Experimental top

A DMF (2 ml) solution of cyclohexanone and 3-(2-methoxyphenyl)acryaldehyde in the presence of L-proline as organocatalyst was stirred at room temperature for 48 h. Then the mixture was washed with water (20 ml) and extracted with ethyl acetate (three times). The organic solvent was removed under reduced pressure and the product was purified by silica gel chromatography (pentane: ethyl acetate mixtures). Suitable crystals were obtained by slow evaporation of ethanol at room temperature.

Refinement top

In the absence of significant anomalous scatterers Friedel pairs were merged prior to refinement. All H atoms were placed in calculated positions with C—H = 0.98 Å (sp), C—H = 0.97 Å (sp2), C—H= 0.96 Å (sp3), C—H = 0.93 Å (aromatic) and O—H = 0.85 Å and included in the final cycles of refinement in a riding motion approximation, with Uiso(H) = 1.2Ueq of the carrier atoms.

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 2006); cell refinement: PROCESS-AUTO (Rigaku, 2006); data reduction: CrystalStructure (Rigaku/MSC, 2004), and Larson (1970); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: CRYSTALS (Watkin et al., 1996); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2004).

Figures top
[Figure 1] Fig. 1. Thermal ellipsoid representation of the of title compound with the atomic labeling scheme. Displacement ellipsoids are drawn at the 40% probability level.
[Figure 2] Fig. 2. View of the hydrogen bonding interactions. H bonds are represented as dashed lines. Symmetery codes: (i) x + 1/2, -y - 1/2, -z. (iv) -x, y + 1/2, 1/2 -z. (v) 1/2 - x, -y - 1, - 1/2 + z.
(2R,4R)-2-Hydroxy-4-(2-methoxyphenyl)bicyclo[3.3.1]nonan-9-one top
Crystal data top
C16H20O3F(000) = 560.00
Mr = 260.33Dx = 1.238 Mg m3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71075 Å
Hall symbol: P 2ac 2abCell parameters from 8871 reflections
a = 6.9378 (5) Åθ = 3.0–27.4°
b = 12.5291 (11) ŵ = 0.08 mm1
c = 16.0726 (14) ÅT = 296 K
V = 1397.1 (2) Å3Chunk, colorless
Z = 40.47 × 0.32 × 0.29 mm
Data collection top
Rigaku R-AXIS RAPID
diffractometer
1211 reflections with F2 > 2σ(F2)
Detector resolution: 10.00 pixels mm-1Rint = 0.034
ω scansθmax = 27.4°
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
h = 88
Tmin = 0.945, Tmax = 0.976k = 1616
13314 measured reflectionsl = 2020
1840 independent reflections
Refinement top
Refinement on F2 w = 1/[1.01σ(Fo2)]/(4Fo2)
R[F2 > 2σ(F2)] = 0.032(Δ/σ)max < 0.001
wR(F2) = 0.061Δρmax = 0.16 e Å3
S = 1.00Δρmin = 0.13 e Å3
1840 reflectionsExtinction correction: Larson (1970), equation 22
173 parametersExtinction coefficient: 649 (27)
H-atom parameters constrained
Crystal data top
C16H20O3V = 1397.1 (2) Å3
Mr = 260.33Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 6.9378 (5) ŵ = 0.08 mm1
b = 12.5291 (11) ÅT = 296 K
c = 16.0726 (14) Å0.47 × 0.32 × 0.29 mm
Data collection top
Rigaku R-AXIS RAPID
diffractometer
1840 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
1211 reflections with F2 > 2σ(F2)
Tmin = 0.945, Tmax = 0.976Rint = 0.034
13314 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.032173 parameters
wR(F2) = 0.061H-atom parameters constrained
S = 1.00Δρmax = 0.16 e Å3
1840 reflectionsΔρmin = 0.13 e Å3
Special details top

Geometry. ENTER SPECIAL DETAILS OF THE MOLECULAR GEOMETRY

Refinement. Refinement using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.3084 (2)0.19303 (10)0.07830 (9)0.0638 (4)
O20.1217 (2)0.10943 (12)0.00114 (9)0.0622 (4)
O30.10291 (19)0.08144 (11)0.23327 (8)0.0593 (4)
C10.1869 (2)0.03037 (14)0.12399 (11)0.0390 (5)
C20.3817 (2)0.00912 (14)0.09036 (12)0.0457 (5)
C30.3617 (2)0.10201 (16)0.02981 (12)0.0476 (5)
C40.2100 (2)0.08335 (16)0.03793 (12)0.0472 (5)
C50.2559 (3)0.00623 (18)0.10098 (12)0.0601 (6)
C60.2481 (3)0.11937 (17)0.06523 (13)0.0657 (7)
C70.0787 (3)0.13738 (16)0.00841 (12)0.0599 (6)
C80.0362 (2)0.04651 (14)0.05297 (12)0.0433 (5)
C90.0240 (2)0.05569 (16)0.00463 (12)0.0440 (5)
C100.1996 (2)0.12898 (14)0.17882 (11)0.0388 (5)
C110.3544 (2)0.19787 (16)0.17853 (12)0.0519 (6)
C120.3625 (3)0.28667 (17)0.23012 (12)0.0653 (7)
C130.2124 (3)0.30819 (18)0.28234 (13)0.0632 (7)
C140.0528 (3)0.24199 (16)0.28470 (12)0.0527 (6)
C150.0475 (2)0.15310 (14)0.23345 (12)0.0437 (5)
C160.2463 (2)0.0914 (2)0.29575 (13)0.0707 (7)
H10.13660.02700.15930.047*
H30.48680.11550.00350.057*
H40.19180.15020.06870.057*
H80.08970.05990.07850.052*
H110.45670.18450.14260.062*
H120.46970.33120.22910.078*
H130.21740.36790.31670.076*
H140.04950.25700.32020.063*
H210.46040.03200.13690.055*
H220.44480.04950.06190.055*
H510.38470.00580.12260.072*
H520.16340.00170.14610.072*
H610.36550.13220.03410.079*
H620.23990.16960.11100.079*
H710.03480.14770.04270.072*
H720.10320.20160.02360.072*
H1010.32630.24880.04980.077*
H1610.32430.02820.29670.085*
H1620.18560.10070.34890.085*
H1630.32600.15220.28390.085*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0884 (9)0.0367 (7)0.0664 (9)0.0155 (8)0.0188 (8)0.0031 (7)
O20.0536 (7)0.0633 (10)0.0698 (10)0.0144 (8)0.0018 (8)0.0159 (9)
O30.0580 (7)0.0607 (9)0.0591 (9)0.0141 (8)0.0173 (7)0.0219 (7)
C10.0433 (9)0.0327 (10)0.0410 (10)0.0023 (8)0.0029 (8)0.0021 (8)
C20.0448 (10)0.0422 (11)0.0502 (12)0.0061 (10)0.0038 (9)0.0003 (10)
C30.0494 (11)0.0398 (11)0.0537 (12)0.0076 (10)0.0110 (10)0.0023 (10)
C40.0553 (11)0.0392 (11)0.0472 (11)0.0009 (10)0.0070 (10)0.0121 (9)
C50.0638 (13)0.0677 (14)0.0488 (12)0.0024 (13)0.0070 (11)0.0001 (11)
C60.0879 (16)0.0525 (14)0.0566 (14)0.0027 (14)0.0052 (13)0.0114 (12)
C70.0857 (15)0.0436 (12)0.0503 (12)0.0147 (12)0.0154 (12)0.0024 (11)
C80.0421 (9)0.0428 (11)0.0452 (10)0.0068 (9)0.0030 (9)0.0122 (10)
C90.0454 (10)0.0447 (11)0.0420 (11)0.0015 (10)0.0025 (9)0.0042 (10)
C100.0491 (10)0.0333 (10)0.0341 (9)0.0000 (9)0.0037 (9)0.0003 (8)
C110.0595 (12)0.0452 (11)0.0509 (12)0.0091 (11)0.0081 (10)0.0048 (10)
C120.0772 (14)0.0512 (14)0.0675 (15)0.0229 (13)0.0124 (13)0.0159 (12)
C130.0856 (15)0.0440 (13)0.0600 (14)0.0115 (13)0.0037 (13)0.0156 (11)
C140.0650 (13)0.0442 (12)0.0488 (12)0.0023 (11)0.0065 (11)0.0104 (10)
C150.0519 (11)0.0396 (11)0.0397 (11)0.0022 (9)0.0024 (10)0.0023 (10)
C160.0503 (12)0.0801 (17)0.0816 (16)0.0057 (13)0.0152 (12)0.0221 (14)
Geometric parameters (Å, º) top
O1—C31.430 (2)O1—H1010.846
O2—C91.216 (2)C1—H10.980
O3—C151.376 (2)C2—H210.970
O3—C161.419 (2)C2—H220.970
C1—C21.537 (2)C3—H30.980
C1—C81.561 (2)C4—H40.980
C1—C101.520 (2)C5—H510.970
C2—C31.523 (2)C5—H520.970
C3—C41.533 (2)C6—H610.970
C4—C51.545 (2)C6—H620.970
C4—C91.501 (2)C7—H710.970
C5—C61.531 (3)C7—H720.970
C6—C71.505 (3)C8—H80.980
C7—C81.535 (2)C11—H110.930
C8—C91.500 (2)C12—H120.930
C10—C111.378 (2)C13—H130.930
C10—C151.406 (2)C14—H140.930
C11—C121.389 (2)C16—H1610.960
C12—C131.365 (3)C16—H1620.960
C13—C141.384 (3)C16—H1630.960
C14—C151.386 (2)
C15—O3—C16118.18 (15)O1—C3—H3109.1
C2—C1—C8111.91 (14)C2—C3—H3109.1
C2—C1—C10114.46 (14)C4—C3—H3109.1
C8—C1—C10110.96 (14)C3—C4—H4108.4
C1—C2—C3112.99 (15)C5—C4—H4108.4
O1—C3—C2106.53 (15)C9—C4—H4108.4
O1—C3—C4109.33 (15)C4—C5—H51108.1
C2—C3—C4113.56 (16)C4—C5—H52108.1
C3—C4—C5115.78 (16)C6—C5—H51108.1
C3—C4—C9107.58 (15)C6—C5—H52108.1
C5—C4—C9107.97 (16)H51—C5—H52109.5
C4—C5—C6114.78 (17)C5—C6—H61108.5
C5—C6—C7113.23 (18)C5—C6—H62108.5
C6—C7—C8115.36 (16)C7—C6—H61108.5
C1—C8—C7115.97 (15)C7—C6—H62108.5
C1—C8—C9107.82 (15)H61—C6—H62109.5
C7—C8—C9108.12 (15)C6—C7—H71108.0
O2—C9—C4124.46 (18)C6—C7—H72108.0
O2—C9—C8122.92 (17)C8—C7—H71108.0
C4—C9—C8112.62 (15)C8—C7—H72108.0
C1—C10—C11123.56 (16)H71—C7—H72109.5
C1—C10—C15119.53 (16)C1—C8—H8108.2
C11—C10—C15116.91 (17)C7—C8—H8108.2
C10—C11—C12122.11 (19)C9—C8—H8108.2
C11—C12—C13119.6 (2)C10—C11—H11118.9
C12—C13—C14120.6 (2)C12—C11—H11118.9
C13—C14—C15119.12 (19)C11—C12—H12120.2
O3—C15—C10115.32 (16)C13—C12—H12120.2
O3—C15—C14123.07 (17)C12—C13—H13119.7
C10—C15—C14121.60 (17)C14—C13—H13119.7
C3—O1—H101109.0C13—C14—H14120.4
C2—C1—H1106.3C15—C14—H14120.4
C8—C1—H1106.3O3—C16—H161109.5
C10—C1—H1106.3O3—C16—H162109.5
C1—C2—H21108.6O3—C16—H163109.5
C1—C2—H22108.6H161—C16—H162109.5
C3—C2—H21108.6H161—C16—H163109.5
C3—C2—H22108.6H162—C16—H163109.5
H21—C2—H22109.5
C16—O3—C15—C10170.27 (16)C5—C4—C9—C862.1 (2)
C16—O3—C15—C148.4 (2)C9—C4—C5—C650.9 (2)
C2—C1—C8—C767.5 (2)C4—C5—C6—C742.5 (2)
C2—C1—C8—C953.83 (19)C5—C6—C7—C842.9 (2)
C8—C1—C2—C347.7 (2)C6—C7—C8—C169.4 (2)
C2—C1—C10—C1119.8 (2)C6—C7—C8—C951.8 (2)
C2—C1—C10—C15160.11 (16)C1—C8—C9—O2116.16 (19)
C10—C1—C2—C3175.04 (15)C1—C8—C9—C463.67 (19)
C8—C1—C10—C11108.0 (2)C7—C8—C9—O2117.7 (2)
C8—C1—C10—C1572.1 (2)C7—C8—C9—C462.4 (2)
C10—C1—C8—C761.7 (2)C1—C10—C11—C12179.26 (18)
C10—C1—C8—C9176.97 (14)C1—C10—C15—O31.2 (2)
C1—C2—C3—O171.93 (19)C1—C10—C15—C14179.90 (17)
C1—C2—C3—C448.5 (2)C11—C10—C15—O3178.77 (16)
O1—C3—C4—C5174.64 (15)C11—C10—C15—C140.0 (2)
O1—C3—C4—C964.54 (19)C15—C10—C11—C120.7 (2)
C2—C3—C4—C566.5 (2)C10—C11—C12—C130.9 (3)
C2—C3—C4—C954.3 (2)C11—C12—C13—C140.4 (3)
C3—C4—C5—C669.7 (2)C12—C13—C14—C150.2 (3)
C3—C4—C9—O2116.3 (2)C13—C14—C15—O3178.22 (18)
C3—C4—C9—C863.5 (2)C13—C14—C15—C100.4 (2)
C5—C4—C9—O2118.0 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H101···O2i0.851.992.8268 (19)171
O1ii—H101ii···O20.851.992.8268 (19)171
C14—H14···O1iii0.932.513.434 (2)176
Symmetry codes: (i) x+1/2, y1/2, z; (ii) x1/2, y1/2, z; (iii) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC16H20O3
Mr260.33
Crystal system, space groupOrthorhombic, P212121
Temperature (K)296
a, b, c (Å)6.9378 (5), 12.5291 (11), 16.0726 (14)
V3)1397.1 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.47 × 0.32 × 0.29
Data collection
DiffractometerRigaku R-AXIS RAPID
diffractometer
Absorption correctionMulti-scan
(ABSCOR; Higashi, 1995)
Tmin, Tmax0.945, 0.976
No. of measured, independent and
observed [F2 > 2σ(F2)] reflections
13314, 1840, 1211
Rint0.034
(sin θ/λ)max1)0.648
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.061, 1.00
No. of reflections1840
No. of parameters173
No. of restraints?
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.16, 0.13

Computer programs: PROCESS-AUTO (Rigaku, 2006), CrystalStructure (Rigaku/MSC, 2004), and Larson (1970), SIR97 (Altomare et al., 1999), CRYSTALS (Watkin et al., 1996), ORTEP-3 for Windows (Farrugia, 1997), CrystalStructure (Rigaku/MSC, 2004).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H101···O2i0.8461.9882.8268 (19)171.3
O1ii—H101ii···O20.8461.9882.8268 (19)171.3
C14—H14···O1iii0.9302.5063.434 (2)176.0
Symmetry codes: (i) x+1/2, y1/2, z; (ii) x1/2, y1/2, z; (iii) x, y+1/2, z+1/2.
 

Acknowledgements

We acknowledge the help of Professor Jianming Gu of Zhejiang University. We are also grateful for financial support from the Natural Science Foundation of Zhejiang Province Education Department (No. Y200803565).

References

First citationAltomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationCao, C., Sun, X., Kang, Y. & Tang, Y. (2007). Org. Lett. 9, 4151–4154.  Web of Science CSD CrossRef PubMed CAS Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationHigashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationLarson, A. C. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, pp. 291–294. Copenhagen: Munksgaard.  Google Scholar
First citationList, B., Lerner, R. A. & Barbas, III (2000). J. Am. Chem. Soc. 122, 2395–2396.  Google Scholar
First citationList, B., Pojarliev, P. & Martin, H. J. (2001). Org. Lett. 3, 2423–2425.  Web of Science CrossRef PubMed CAS Google Scholar
First citationNotz, W., Sakthivel, K., Bui, T., Zhong, G. & Barbas, C. F. III (2001). Tetrahedron Lett. 42, 199–201.  Web of Science CrossRef CAS Google Scholar
First citationRigaku (2006). PROCESS-AUTO Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationRigaku/MSC (2004). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA.  Google Scholar
First citationWatkin, D. J., Prout, C. K., Carruthers, J. R. & Betteridge, P. W. (1996). CRYSTALS. Chemical Crystallography Laboratory, Oxford, England.  Google Scholar

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