organic compounds
(4aR,9R,9aR)-7-Bromo-9-nitromethyl-2,3,4,4a,9,9a-hexahydro-1H-xanthen-1-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: xiaaibao@zjut.edu.cn
The title compound, C14H14BrNO4, contains a tricyclic ring system including three contiguous stereocenters all of which exhibit an R configuration. The cyclohexanone ring adopts a chair conformation. The central oxane ring assumes a strained with five of the ring atoms being nearly coplanar with the bromophenyl group and with the C atom adjacent to the O atom and fused with the cyclohexanone ring as the flap. In the crystal, molecules are linked into a three-dimensional network by C—H⋯O interactions.
Related literature
For related structures, see: Shi et al. (2004); Xia et al. (2009); Ndjakou Lenta et al. (2007). For background information on domino reactions, see Enders et al. (2007); Yu & Wang (2002).
Experimental
Crystal data
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Data collection: PROCESS-AUTO (Rigaku, 2006); cell 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).
Supporting information
https://doi.org/10.1107/S1600536813008659/fy2090sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813008659/fy2090Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536813008659/fy2090Isup3.cml
To the solution of the catalyst (S)-2-(pyrrolidin-2-ylmethylthio)pyridine (20 mol%) and 4-(trifluoromethyl)benzoic acid (10 mol%) in saturated aqueous NaCl (0.25 ml) was added sequentially cyclohexenone (0.8 mmol) and (E)-4-bromo-2-(2-nitrovinyl)phenol (0.2 mmol) at room temperature with vigorous stirring. After completion, the reaction mixture was extracted with EtOAc (3*10 ml), washed with water, dried and concentrated. The residue was purified by flash
to the product. Then, suitable crystals of the title compound were obtained by slow evaporation of methanol solution at room temperature.H atoms were placed in calculated position with C—H=0.98 Å(sp), C—H=0.97 Å(sp2), C—H=0.93 Å(aromatic). All H atoms were included in the final cycles of
as riding mode, with Uiso(H)=1.2Ueq of the carrier atoms.Domino or cascade reactions, in which multiple new bonds and stereocenters could be formed, have been getting more interest in asymmetric organocatalysis (Enders et al., 2007; Yu et al., 2002) . The title compound, (I), was synthesized as one of a series of oxa-Michael-Michael products under investigation.
In this paper, the crystal of title compound (4aR,9R,9aR)-7-bromo-9- (nitromethyl)-2,3,4,4a,9,9a-hexahydro-1H-xanthen-1-one was determined. The structure of (I) is shown in Fig. 1. The O1—C4 bond and the bromophenyl group are almost coplanar: the angle is 3.2 (6) ° between the plane of the bromophenyl ring and the O1—C4—C12 plane. The C11—C12 bond and the bromophenyl plane enclose an angle of 9.4 (7) °. The cyclohexanone ring (C5—C6—C7—C8—C9—C10) adopts a chair conformation. The conformation of the oxane ring is nonstandard. Five atoms of the oxane ring are coplanar with the bromophenyl group and only C5 deviates significantly from the common plane.
For related structures, see: Shi et al. (2004); Xia et al. (2009); Ndjakou Lenta et al. (2007). For background information on domino reactions, see Enders et al. (2007); Yu & Wang (2002).
Data collection: PROCESS-AUTO (Rigaku, 2006); cell
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).Fig. 1. The asymmetric unit of the structure of the title compound, with the atomic labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. | |
Fig. 2. Unit cell packing of the title compound. |
C14H14BrNO4 | F(000) = 344 |
Mr = 340.17 | Dx = 1.547 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 4391 reflections |
a = 10.3457 (7) Å | θ = 3.2–27.4° |
b = 5.4662 (5) Å | µ = 2.83 mm−1 |
c = 13.2446 (12) Å | T = 296 K |
β = 102.849 (2)° | Platelet, colorless |
V = 730.25 (11) Å3 | 0.53 × 0.47 × 0.14 mm |
Z = 2 |
Rigaku R-AXIS RAPID diffractometer | 2655 independent reflections |
Radiation source: rotating anode | 1537 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.061 |
Detector resolution: 10.00 pixels mm-1 | θmax = 26.0°, θmin = 3.2° |
ω scans | h = −12→12 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −6→6 |
Tmin = 0.224, Tmax = 0.673 | l = −16→16 |
6335 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.052 | H-atom parameters constrained |
wR(F2) = 0.137 | w = 1/[σ2(Fo2) + (0.0525P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.00 | (Δ/σ)max < 0.001 |
2655 reflections | Δρmax = 0.36 e Å−3 |
181 parameters | Δρmin = −0.46 e Å−3 |
1 restraint | Absolute structure: Flack (1983), 1058 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.021 (17) |
C14H14BrNO4 | V = 730.25 (11) Å3 |
Mr = 340.17 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 10.3457 (7) Å | µ = 2.83 mm−1 |
b = 5.4662 (5) Å | T = 296 K |
c = 13.2446 (12) Å | 0.53 × 0.47 × 0.14 mm |
β = 102.849 (2)° |
Rigaku R-AXIS RAPID diffractometer | 2655 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 1537 reflections with I > 2σ(I) |
Tmin = 0.224, Tmax = 0.673 | Rint = 0.061 |
6335 measured reflections |
R[F2 > 2σ(F2)] = 0.052 | H-atom parameters constrained |
wR(F2) = 0.137 | Δρmax = 0.36 e Å−3 |
S = 1.00 | Δρmin = −0.46 e Å−3 |
2655 reflections | Absolute structure: Flack (1983), 1058 Friedel pairs |
181 parameters | Absolute structure parameter: 0.021 (17) |
1 restraint |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.1121 (7) | 0.9599 (12) | 0.3568 (5) | 0.0740 (18) | |
C2 | 0.2242 (7) | 0.9776 (13) | 0.4388 (6) | 0.084 (2) | |
H2 | 0.2201 | 1.0658 | 0.4980 | 0.101* | |
C3 | 0.3408 (7) | 0.8631 (13) | 0.4308 (5) | 0.079 (2) | |
H3 | 0.4154 | 0.8757 | 0.4847 | 0.095* | |
C4 | 0.3469 (5) | 0.7291 (10) | 0.3426 (5) | 0.0575 (14) | |
C5 | 0.4665 (5) | 0.4397 (10) | 0.2629 (5) | 0.0594 (15) | |
H5 | 0.4212 | 0.2917 | 0.2785 | 0.071* | |
C6 | 0.6112 (5) | 0.3829 (12) | 0.2656 (6) | 0.074 (2) | |
H6A | 0.6535 | 0.3222 | 0.3337 | 0.089* | |
H6B | 0.6160 | 0.2555 | 0.2156 | 0.089* | |
C7 | 0.6840 (5) | 0.6043 (15) | 0.2415 (5) | 0.0816 (19) | |
H7A | 0.7741 | 0.5588 | 0.2397 | 0.098* | |
H7B | 0.6882 | 0.7244 | 0.2960 | 0.098* | |
C8 | 0.6170 (5) | 0.7183 (13) | 0.1378 (6) | 0.077 (2) | |
H8A | 0.6599 | 0.8722 | 0.1292 | 0.092* | |
H8B | 0.6273 | 0.6101 | 0.0820 | 0.092* | |
C9 | 0.4716 (5) | 0.7627 (10) | 0.1311 (4) | 0.0553 (14) | |
C10 | 0.3944 (4) | 0.5445 (8) | 0.1576 (4) | 0.0461 (12) | |
H10 | 0.3945 | 0.4183 | 0.1050 | 0.055* | |
C11 | 0.2504 (4) | 0.6049 (10) | 0.1573 (4) | 0.0487 (12) | |
H11 | 0.2196 | 0.7266 | 0.1029 | 0.058* | |
C12 | 0.2391 (5) | 0.7152 (9) | 0.2586 (5) | 0.0518 (14) | |
C13 | 0.1217 (6) | 0.8341 (11) | 0.2703 (5) | 0.0650 (16) | |
H13 | 0.0473 | 0.8255 | 0.2160 | 0.078* | |
C14 | 0.1623 (5) | 0.3767 (10) | 0.1314 (5) | 0.0572 (15) | |
H14A | 0.2038 | 0.2403 | 0.1732 | 0.069* | |
H14B | 0.0773 | 0.4073 | 0.1485 | 0.069* | |
N1 | 0.1410 (4) | 0.3111 (10) | 0.0188 (5) | 0.0621 (14) | |
O1 | 0.4667 (3) | 0.6210 (10) | 0.3413 (3) | 0.0647 (10) | |
O2 | 0.4213 (4) | 0.9576 (7) | 0.1075 (4) | 0.0745 (13) | |
O3 | 0.1104 (4) | 0.0988 (9) | −0.0041 (4) | 0.1026 (17) | |
O4 | 0.1497 (5) | 0.4689 (10) | −0.0439 (4) | 0.0874 (14) | |
Br1 | −0.04348 (7) | 1.1196 (2) | 0.36550 (7) | 0.1208 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.094 (4) | 0.080 (4) | 0.048 (5) | 0.010 (3) | 0.015 (4) | −0.003 (4) |
C2 | 0.096 (5) | 0.101 (5) | 0.057 (5) | 0.017 (4) | 0.022 (4) | −0.021 (4) |
C3 | 0.091 (5) | 0.100 (5) | 0.042 (4) | 0.014 (4) | 0.003 (3) | −0.012 (4) |
C4 | 0.064 (3) | 0.065 (3) | 0.044 (4) | 0.008 (3) | 0.015 (3) | 0.007 (3) |
C5 | 0.063 (3) | 0.065 (3) | 0.050 (4) | 0.008 (3) | 0.011 (3) | 0.009 (3) |
C6 | 0.045 (3) | 0.093 (4) | 0.078 (5) | 0.008 (3) | −0.002 (3) | −0.024 (4) |
C7 | 0.046 (3) | 0.098 (5) | 0.096 (5) | 0.001 (4) | 0.004 (3) | −0.019 (5) |
C8 | 0.069 (4) | 0.080 (4) | 0.087 (6) | 0.000 (3) | 0.029 (4) | −0.008 (4) |
C9 | 0.066 (3) | 0.061 (4) | 0.037 (4) | −0.004 (3) | 0.008 (3) | −0.005 (3) |
C10 | 0.053 (2) | 0.047 (3) | 0.039 (3) | 0.000 (2) | 0.011 (2) | −0.009 (2) |
C11 | 0.057 (2) | 0.044 (2) | 0.044 (3) | −0.002 (3) | 0.009 (2) | 0.005 (3) |
C12 | 0.053 (3) | 0.054 (3) | 0.050 (4) | 0.003 (2) | 0.013 (2) | 0.006 (2) |
C13 | 0.070 (3) | 0.066 (4) | 0.059 (5) | −0.001 (3) | 0.013 (3) | 0.010 (3) |
C14 | 0.047 (3) | 0.056 (3) | 0.069 (5) | −0.006 (2) | 0.013 (3) | 0.001 (3) |
N1 | 0.037 (2) | 0.072 (3) | 0.073 (4) | 0.011 (2) | 0.002 (2) | −0.010 (3) |
O1 | 0.063 (2) | 0.086 (2) | 0.040 (2) | 0.016 (2) | 0.0012 (16) | −0.008 (2) |
O2 | 0.084 (3) | 0.056 (2) | 0.083 (4) | −0.013 (2) | 0.017 (2) | 0.011 (2) |
O3 | 0.097 (3) | 0.070 (3) | 0.123 (4) | −0.004 (3) | −0.015 (3) | −0.040 (3) |
O4 | 0.104 (3) | 0.105 (4) | 0.052 (3) | −0.013 (3) | 0.013 (3) | −0.012 (3) |
Br1 | 0.1011 (5) | 0.1479 (8) | 0.1168 (8) | 0.0504 (6) | 0.0314 (5) | −0.0231 (7) |
C1—C13 | 1.359 (9) | C7—H7B | 0.9700 |
C1—C2 | 1.405 (9) | C8—C9 | 1.506 (8) |
C1—Br1 | 1.857 (6) | C8—H8A | 0.9700 |
C2—C3 | 1.383 (8) | C8—H8B | 0.9700 |
C2—H2 | 0.9300 | C9—O2 | 1.196 (6) |
C3—C4 | 1.393 (8) | C9—C10 | 1.519 (7) |
C3—H3 | 0.9300 | C10—C11 | 1.525 (6) |
C4—O1 | 1.376 (6) | C10—H10 | 0.9800 |
C4—C12 | 1.391 (7) | C11—C12 | 1.499 (7) |
C5—O1 | 1.435 (8) | C11—C14 | 1.538 (7) |
C5—C6 | 1.521 (7) | C11—H11 | 0.9800 |
C5—C10 | 1.538 (8) | C12—C13 | 1.417 (7) |
C5—H5 | 0.9800 | C13—H13 | 0.9300 |
C6—C7 | 1.497 (10) | C14—N1 | 1.502 (8) |
C6—H6A | 0.9700 | C14—H14A | 0.9700 |
C6—H6B | 0.9700 | C14—H14B | 0.9700 |
C7—C8 | 1.527 (9) | N1—O4 | 1.214 (6) |
C7—H7A | 0.9700 | N1—O3 | 1.223 (7) |
C13—C1—C2 | 119.0 (6) | C7—C8—H8B | 109.3 |
C13—C1—Br1 | 121.1 (5) | H8A—C8—H8B | 108.0 |
C2—C1—Br1 | 119.8 (5) | O2—C9—C8 | 122.0 (5) |
C3—C2—C1 | 119.6 (6) | O2—C9—C10 | 122.6 (5) |
C3—C2—H2 | 120.2 | C8—C9—C10 | 115.4 (5) |
C1—C2—H2 | 120.2 | C9—C10—C11 | 113.1 (4) |
C2—C3—C4 | 120.3 (6) | C9—C10—C5 | 109.1 (4) |
C2—C3—H3 | 119.8 | C11—C10—C5 | 111.1 (4) |
C4—C3—H3 | 119.8 | C9—C10—H10 | 107.8 |
O1—C4—C3 | 116.4 (5) | C11—C10—H10 | 107.8 |
O1—C4—C12 | 122.0 (5) | C5—C10—H10 | 107.8 |
C3—C4—C12 | 121.5 (5) | C12—C11—C10 | 110.8 (4) |
O1—C5—C6 | 106.3 (5) | C12—C11—C14 | 111.4 (4) |
O1—C5—C10 | 108.8 (4) | C10—C11—C14 | 110.8 (4) |
C6—C5—C10 | 111.9 (5) | C12—C11—H11 | 107.9 |
O1—C5—H5 | 109.9 | C10—C11—H11 | 107.9 |
C6—C5—H5 | 109.9 | C14—C11—H11 | 107.9 |
C10—C5—H5 | 109.9 | C4—C12—C13 | 116.2 (5) |
C7—C6—C5 | 111.7 (5) | C4—C12—C11 | 122.0 (5) |
C7—C6—H6A | 109.3 | C13—C12—C11 | 121.5 (5) |
C5—C6—H6A | 109.3 | C1—C13—C12 | 123.3 (6) |
C7—C6—H6B | 109.3 | C1—C13—H13 | 118.3 |
C5—C6—H6B | 109.3 | C12—C13—H13 | 118.3 |
H6A—C6—H6B | 107.9 | N1—C14—C11 | 111.3 (5) |
C6—C7—C8 | 111.8 (5) | N1—C14—H14A | 109.4 |
C6—C7—H7A | 109.2 | C11—C14—H14A | 109.4 |
C8—C7—H7A | 109.2 | N1—C14—H14B | 109.4 |
C6—C7—H7B | 109.2 | C11—C14—H14B | 109.4 |
C8—C7—H7B | 109.2 | H14A—C14—H14B | 108.0 |
H7A—C7—H7B | 107.9 | O4—N1—O3 | 124.0 (6) |
C9—C8—C7 | 111.5 (6) | O4—N1—C14 | 119.5 (5) |
C9—C8—H8A | 109.3 | O3—N1—C14 | 116.4 (6) |
C7—C8—H8A | 109.3 | C4—O1—C5 | 116.7 (4) |
C9—C8—H8B | 109.3 | ||
C13—C1—C2—C3 | −1.3 (11) | C5—C10—C11—C14 | −84.5 (5) |
Br1—C1—C2—C3 | −178.5 (6) | O1—C4—C12—C13 | 179.8 (5) |
C1—C2—C3—C4 | −0.6 (11) | C3—C4—C12—C13 | −3.2 (9) |
C2—C3—C4—O1 | −179.9 (6) | O1—C4—C12—C11 | −6.6 (8) |
C2—C3—C4—C12 | 2.9 (11) | C3—C4—C12—C11 | 170.4 (6) |
O1—C5—C6—C7 | −61.4 (7) | C10—C11—C12—C4 | −6.8 (7) |
C10—C5—C6—C7 | 57.2 (7) | C14—C11—C12—C4 | 117.0 (5) |
C5—C6—C7—C8 | −55.4 (7) | C10—C11—C12—C13 | 166.4 (4) |
C6—C7—C8—C9 | 51.6 (7) | C14—C11—C12—C13 | −69.8 (6) |
C7—C8—C9—O2 | 128.3 (7) | C2—C1—C13—C12 | 1.0 (10) |
C7—C8—C9—C10 | −51.1 (7) | Br1—C1—C13—C12 | 178.1 (4) |
O2—C9—C10—C11 | −3.6 (8) | C4—C12—C13—C1 | 1.2 (9) |
C8—C9—C10—C11 | 175.8 (5) | C11—C12—C13—C1 | −172.4 (6) |
O2—C9—C10—C5 | −127.8 (6) | C12—C11—C14—N1 | 162.8 (4) |
C8—C9—C10—C5 | 51.6 (6) | C10—C11—C14—N1 | −73.3 (5) |
O1—C5—C10—C9 | 63.7 (5) | C11—C14—N1—O4 | −25.2 (6) |
C6—C5—C10—C9 | −53.5 (6) | C11—C14—N1—O3 | 157.5 (4) |
O1—C5—C10—C11 | −61.7 (5) | C3—C4—O1—C5 | 166.4 (6) |
C6—C5—C10—C11 | −178.9 (5) | C12—C4—O1—C5 | −16.5 (8) |
C9—C10—C11—C12 | −83.4 (6) | C6—C5—O1—C4 | 170.2 (5) |
C5—C10—C11—C12 | 39.7 (6) | C10—C5—O1—C4 | 49.5 (7) |
C9—C10—C11—C14 | 152.4 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O1i | 0.93 | 2.71 | 3.520 (9) | 146 |
C8—H8B···O2ii | 0.97 | 2.59 | 3.489 (6) | 155 |
C8—H8A···O4iii | 0.97 | 2.54 | 3.253 (4) | 131 |
C10—H10···O2iv | 0.98 | 2.53 | 3.300 (8) | 135 |
C11—H11···O3v | 0.98 | 2.59 | 3.547 (8) | 165 |
Symmetry codes: (i) −x+1, y+1/2, −z+1; (ii) −x+1, y−1/2, −z; (iii) −x+1, y+1/2, −z; (iv) x, y−1, z; (v) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C14H14BrNO4 |
Mr | 340.17 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 296 |
a, b, c (Å) | 10.3457 (7), 5.4662 (5), 13.2446 (12) |
β (°) | 102.849 (2) |
V (Å3) | 730.25 (11) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.83 |
Crystal size (mm) | 0.53 × 0.47 × 0.14 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.224, 0.673 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6335, 2655, 1537 |
Rint | 0.061 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.052, 0.137, 1.00 |
No. of reflections | 2655 |
No. of parameters | 181 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.36, −0.46 |
Absolute structure | Flack (1983), 1058 Friedel pairs |
Absolute structure parameter | 0.021 (17) |
Computer programs: PROCESS-AUTO (Rigaku, 2006), CrystalStructure (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), WinGX (Farrugia, 2012).
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O1i | 0.930 | 2.710 | 3.520 (9) | 146 |
C8—H8B···O2ii | 0.971 | 2.586 | 3.489 (6) | 155 |
C8—H8A···O4iii | 0.970 | 2.535 | 3.253 (4) | 131 |
C10—H10···O2iv | 0.981 | 2.533 | 3.300 (8) | 135 |
C11—H11···O3v | 0.980 | 2.591 | 3.547 (8) | 165 |
Symmetry codes: (i) −x+1, y+1/2, −z+1; (ii) −x+1, y−1/2, −z; (iii) −x+1, y+1/2, −z; (iv) x, y−1, z; (v) x, y+1, z. |
Acknowledgements
The authors thank Professor Jian-Ming Gu of Zhejiang University for his help.
References
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Domino or cascade reactions, in which multiple new bonds and stereocenters could be formed, have been getting more interest in asymmetric organocatalysis (Enders et al., 2007; Yu et al., 2002) . The title compound, (I), was synthesized as one of a series of oxa-Michael-Michael products under investigation.
In this paper, the crystal of title compound (4aR,9R,9aR)-7-bromo-9- (nitromethyl)-2,3,4,4a,9,9a-hexahydro-1H-xanthen-1-one was determined. The structure of (I) is shown in Fig. 1. The O1—C4 bond and the bromophenyl group are almost coplanar: the angle is 3.2 (6) ° between the plane of the bromophenyl ring and the O1—C4—C12 plane. The C11—C12 bond and the bromophenyl plane enclose an angle of 9.4 (7) °. The cyclohexanone ring (C5—C6—C7—C8—C9—C10) adopts a chair conformation. The conformation of the oxane ring is nonstandard. Five atoms of the oxane ring are coplanar with the bromophenyl group and only C5 deviates significantly from the common plane.