organic compounds
(1S,3R,8R)-2,2-Dibromo-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodec-9-en-11-one
aLaboratoire de Chimie des Substances Naturelles, "Unité Associé au CNRST (URAC16)", Faculté des Sciences Semlalia, BP 2390 Bd My Abdellah, 40000 Marrakech, Morocco, and bLaboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Avenue Ibn Battouta, BP 1014 Rabat, Morocco
*Correspondence e-mail: berraho@uca.ma
The title compound, C16H22Br2O, was synthesized from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The molecule is built up from fused six- and seven-membered rings and an additional three-membered ring from the reaction of himachalene with dibromocarbene. The six-membered ring has an with the C atom belonging to the three-membered ring forming the flap, whereas the seven-membered ring displays a screw-boat conformation; the dihedral angle between the rings (all atoms) is 60.92 (16)°.
Related literature
For the isolation of β-himachalene, see: Joseph & Dev (1968); Plattier & Teiseire (1974). For the reactivity of this sesquiterpene, see: Lassaba et al. (1997); Chekroun et al. (2000); El Jamili et al. (2002); Sbai et al. (2002); Dakir et al. (2004). For its biological activity, see: Daoubi et al. (2004). For see: Cremer & Pople (1975).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; 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
10.1107/S1600536812046089/go2074sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812046089/go2074Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812046089/go2074Isup3.cml
In a reactor containing a solution of (1S, 3R, 8R)-2,2-dibromo- 3,7,7,10 tetramethyltricyclo [6.4.0.01,3] dodec-9-ene (1 g, 2,6 mmol) in 50 ml of tetrahydrofuran and water (THF/H2O) (4:1) cooled to 273 K and kept in the dark, was added in small portions 1 g (5,6 mmol) of N-bromosccinimide. The reaction mixture was left stirring for 1 h, after which 20 ml of a
of NaHCO3 was added. Subsequently, the extraction was performed three times with diethyl ether (3 x 20 ml). The organic extracts were dried over Na2SO4, filtered, concentrated, and chromatographed. The title compound was obtained with a yield of 80% and was recrystallized in n-pentane.All H atoms were fixed geometrically and treated as riding with C—H = 0.96 Å (methyl),0.97 Å (methylene), 0.98 Å (methine) with Uiso(H) = 1.2Ueq(methylene, methine) or Uiso(H) = 1.5Ueq(methyl).
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); 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).C16H22Br2O | F(000) = 784 |
Mr = 390.16 | Dx = 1.593 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 11891 reflections |
a = 6.7369 (1) Å | θ = 2.8–26.4° |
b = 14.7635 (3) Å | µ = 4.98 mm−1 |
c = 16.3543 (3) Å | T = 298 K |
V = 1626.60 (5) Å3 | Prism, colourless |
Z = 4 | 0.80 × 0.65 × 0.25 mm |
Bruker APEXII CCD diffractometer | 3330 independent reflections |
Radiation source: fine-focus sealed tube | 2939 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.028 |
ω and ϕ scans | θmax = 26.4°, θmin = 2.9° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | h = −7→8 |
Tmin = 0.259, Tmax = 0.746 | k = −18→18 |
11891 measured reflections | l = −20→20 |
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)] = 0.030 | H-atom parameters constrained |
wR(F2) = 0.074 | w = 1/[σ2(Fo2) + (0.034P)2 + 0.368P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.001 |
3330 reflections | Δρmax = 0.68 e Å−3 |
176 parameters | Δρmin = −0.37 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 1397 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.021 (12) |
C16H22Br2O | V = 1626.60 (5) Å3 |
Mr = 390.16 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 6.7369 (1) Å | µ = 4.98 mm−1 |
b = 14.7635 (3) Å | T = 298 K |
c = 16.3543 (3) Å | 0.80 × 0.65 × 0.25 mm |
Bruker APEXII CCD diffractometer | 3330 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2939 reflections with I > 2σ(I) |
Tmin = 0.259, Tmax = 0.746 | Rint = 0.028 |
11891 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | H-atom parameters constrained |
wR(F2) = 0.074 | Δρmax = 0.68 e Å−3 |
S = 1.06 | Δρmin = −0.37 e Å−3 |
3330 reflections | Absolute structure: Flack (1983), 1397 Friedel pairs |
176 parameters | Absolute structure parameter: 0.021 (12) |
0 restraints |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | 0.7886 (4) | 0.8949 (2) | 0.72986 (18) | 0.0345 (7) | |
C2 | 0.7652 (4) | 0.8664 (2) | 0.8186 (2) | 0.0381 (7) | |
C3 | 0.8277 (5) | 0.9620 (2) | 0.79993 (18) | 0.0381 (7) | |
C4 | 0.6771 (5) | 1.0379 (2) | 0.8104 (2) | 0.0458 (8) | |
H4A | 0.7011 | 1.0681 | 0.8621 | 0.055* | |
H4B | 0.5449 | 1.0120 | 0.8124 | 0.055* | |
C5 | 0.6854 (6) | 1.1078 (2) | 0.7417 (2) | 0.0545 (9) | |
H5A | 0.5580 | 1.1383 | 0.7392 | 0.065* | |
H5B | 0.7842 | 1.1529 | 0.7560 | 0.065* | |
C6 | 0.7335 (7) | 1.0720 (3) | 0.6570 (3) | 0.0635 (11) | |
H6A | 0.8704 | 1.0516 | 0.6578 | 0.076* | |
H6B | 0.7270 | 1.1228 | 0.6195 | 0.076* | |
C7 | 0.6078 (5) | 0.9950 (2) | 0.62020 (19) | 0.0411 (7) | |
C8 | 0.6031 (4) | 0.9087 (2) | 0.67808 (18) | 0.0353 (7) | |
H8 | 0.4927 | 0.9177 | 0.7163 | 0.042* | |
C9 | 0.5589 (4) | 0.8232 (2) | 0.63150 (19) | 0.0417 (7) | |
H9 | 0.4286 | 0.8142 | 0.6145 | 0.050* | |
C10 | 0.6912 (5) | 0.7587 (2) | 0.61230 (18) | 0.0391 (7) | |
C11 | 0.9012 (4) | 0.7704 (2) | 0.63421 (19) | 0.0399 (7) | |
C12 | 0.9602 (4) | 0.8536 (2) | 0.68244 (19) | 0.0420 (7) | |
H12A | 1.0130 | 0.8986 | 0.6451 | 0.050* | |
H12B | 1.0649 | 0.8374 | 0.7204 | 0.050* | |
C13 | 1.0396 (5) | 0.9900 (3) | 0.8188 (2) | 0.0537 (9) | |
H13A | 1.1285 | 0.9418 | 0.8042 | 0.081* | |
H13B | 1.0520 | 1.0026 | 0.8762 | 0.081* | |
H13C | 1.0724 | 1.0434 | 0.7881 | 0.081* | |
C14 | 0.3936 (7) | 1.0248 (3) | 0.6061 (3) | 0.0832 (15) | |
H14A | 0.3917 | 1.0760 | 0.5699 | 0.125* | |
H14B | 0.3345 | 1.0413 | 0.6574 | 0.125* | |
H14C | 0.3200 | 0.9759 | 0.5821 | 0.125* | |
C15 | 0.6966 (8) | 0.9745 (3) | 0.5362 (3) | 0.0758 (13) | |
H15A | 0.8355 | 0.9615 | 0.5419 | 0.114* | |
H15B | 0.6796 | 1.0261 | 0.5011 | 0.114* | |
H15C | 0.6304 | 0.9231 | 0.5128 | 0.114* | |
C16 | 0.6372 (7) | 0.6755 (2) | 0.5647 (2) | 0.0584 (10) | |
H16A | 0.4981 | 0.6768 | 0.5520 | 0.088* | |
H16B | 0.6662 | 0.6226 | 0.5967 | 0.088* | |
H16C | 0.7126 | 0.6738 | 0.5149 | 0.088* | |
Br1 | 0.50492 (5) | 0.83972 (3) | 0.86363 (2) | 0.05453 (12) | |
Br2 | 0.94858 (5) | 0.78265 (3) | 0.86827 (3) | 0.06271 (13) | |
O | 1.0289 (4) | 0.71769 (17) | 0.61207 (15) | 0.0604 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0291 (15) | 0.0354 (17) | 0.0390 (16) | 0.0008 (13) | 0.0031 (12) | −0.0040 (14) |
C2 | 0.0293 (14) | 0.0415 (18) | 0.0434 (17) | 0.0048 (12) | 0.0006 (12) | −0.0004 (15) |
C3 | 0.0355 (15) | 0.0398 (17) | 0.0391 (16) | −0.0008 (14) | 0.0006 (13) | −0.0075 (14) |
C4 | 0.0517 (19) | 0.0401 (18) | 0.0456 (18) | 0.0045 (16) | 0.0033 (15) | −0.0135 (16) |
C5 | 0.070 (2) | 0.0361 (19) | 0.057 (2) | 0.0011 (18) | −0.0057 (19) | −0.0068 (18) |
C6 | 0.078 (3) | 0.045 (2) | 0.067 (3) | −0.006 (2) | −0.003 (2) | 0.002 (2) |
C7 | 0.0458 (16) | 0.0382 (16) | 0.0393 (17) | −0.0022 (14) | −0.0020 (14) | 0.0005 (15) |
C8 | 0.0297 (14) | 0.0371 (17) | 0.0393 (15) | −0.0010 (13) | 0.0013 (12) | −0.0028 (14) |
C9 | 0.0397 (14) | 0.0435 (17) | 0.0419 (16) | −0.0081 (13) | −0.0024 (15) | −0.0010 (16) |
C10 | 0.0522 (18) | 0.0337 (16) | 0.0316 (15) | −0.0068 (14) | 0.0025 (13) | 0.0004 (13) |
C11 | 0.0483 (16) | 0.0338 (16) | 0.0376 (15) | 0.0066 (14) | 0.0120 (15) | 0.0031 (15) |
C12 | 0.0323 (15) | 0.0471 (18) | 0.0465 (17) | 0.0037 (14) | 0.0048 (13) | −0.0093 (15) |
C13 | 0.0470 (19) | 0.058 (2) | 0.0559 (19) | −0.0065 (18) | −0.0019 (16) | −0.0152 (18) |
C14 | 0.069 (3) | 0.079 (3) | 0.102 (4) | 0.008 (2) | −0.009 (2) | 0.042 (3) |
C15 | 0.095 (3) | 0.072 (3) | 0.061 (2) | −0.010 (3) | 0.012 (2) | 0.009 (2) |
C16 | 0.086 (3) | 0.037 (2) | 0.052 (2) | −0.009 (2) | −0.0035 (19) | 0.0003 (17) |
Br1 | 0.04425 (17) | 0.0613 (2) | 0.0581 (2) | −0.00202 (17) | 0.01213 (17) | 0.00965 (18) |
Br2 | 0.0559 (2) | 0.0613 (2) | 0.0710 (2) | 0.01579 (18) | −0.00973 (19) | 0.0117 (2) |
O | 0.0663 (16) | 0.0493 (14) | 0.0657 (14) | 0.0148 (14) | 0.0091 (13) | −0.0101 (12) |
C1—C2 | 1.518 (4) | C8—H8 | 0.9800 |
C1—C12 | 1.520 (4) | C9—C10 | 1.341 (5) |
C1—C8 | 1.524 (4) | C9—H9 | 0.9300 |
C1—C3 | 1.537 (4) | C10—C11 | 1.470 (4) |
C2—C3 | 1.503 (5) | C10—C16 | 1.499 (5) |
C2—Br2 | 1.928 (3) | C11—O | 1.216 (4) |
C2—Br1 | 1.943 (3) | C11—C12 | 1.512 (5) |
C3—C13 | 1.518 (4) | C12—H12A | 0.9700 |
C3—C4 | 1.522 (5) | C12—H12B | 0.9700 |
C4—C5 | 1.526 (5) | C13—H13A | 0.9600 |
C4—H4A | 0.9700 | C13—H13B | 0.9600 |
C4—H4B | 0.9700 | C13—H13C | 0.9600 |
C5—C6 | 1.517 (5) | C14—H14A | 0.9600 |
C5—H5A | 0.9700 | C14—H14B | 0.9600 |
C5—H5B | 0.9700 | C14—H14C | 0.9600 |
C6—C7 | 1.541 (5) | C15—H15A | 0.9600 |
C6—H6A | 0.9700 | C15—H15B | 0.9600 |
C6—H6B | 0.9700 | C15—H15C | 0.9600 |
C7—C14 | 1.526 (5) | C16—H16A | 0.9600 |
C7—C15 | 1.529 (5) | C16—H16B | 0.9600 |
C7—C8 | 1.587 (5) | C16—H16C | 0.9600 |
C8—C9 | 1.505 (4) | ||
C2—C1—C12 | 117.1 (3) | C1—C8—C7 | 115.0 (2) |
C2—C1—C8 | 118.9 (2) | C9—C8—H8 | 106.6 |
C12—C1—C8 | 113.2 (2) | C1—C8—H8 | 106.6 |
C2—C1—C3 | 58.9 (2) | C7—C8—H8 | 106.6 |
C12—C1—C3 | 120.6 (3) | C10—C9—C8 | 125.7 (3) |
C8—C1—C3 | 117.9 (3) | C10—C9—H9 | 117.2 |
C3—C2—C1 | 61.1 (2) | C8—C9—H9 | 117.2 |
C3—C2—Br2 | 120.5 (2) | C9—C10—C11 | 119.9 (3) |
C1—C2—Br2 | 120.9 (2) | C9—C10—C16 | 122.8 (3) |
C3—C2—Br1 | 121.3 (2) | C11—C10—C16 | 117.2 (3) |
C1—C2—Br1 | 120.8 (2) | O—C11—C10 | 122.2 (3) |
Br2—C2—Br1 | 106.75 (16) | O—C11—C12 | 119.3 (3) |
C2—C3—C13 | 118.5 (3) | C10—C11—C12 | 118.4 (3) |
C2—C3—C4 | 118.8 (3) | C11—C12—C1 | 113.1 (3) |
C13—C3—C4 | 113.8 (3) | C11—C12—H12A | 109.0 |
C2—C3—C1 | 59.9 (2) | C1—C12—H12A | 109.0 |
C13—C3—C1 | 119.3 (3) | C11—C12—H12B | 109.0 |
C4—C3—C1 | 116.4 (3) | C1—C12—H12B | 109.0 |
C3—C4—C5 | 113.0 (3) | H12A—C12—H12B | 107.8 |
C3—C4—H4A | 109.0 | C3—C13—H13A | 109.5 |
C5—C4—H4A | 109.0 | C3—C13—H13B | 109.5 |
C3—C4—H4B | 109.0 | H13A—C13—H13B | 109.5 |
C5—C4—H4B | 109.0 | C3—C13—H13C | 109.5 |
H4A—C4—H4B | 107.8 | H13A—C13—H13C | 109.5 |
C6—C5—C4 | 116.4 (3) | H13B—C13—H13C | 109.5 |
C6—C5—H5A | 108.2 | C7—C14—H14A | 109.5 |
C4—C5—H5A | 108.2 | C7—C14—H14B | 109.5 |
C6—C5—H5B | 108.2 | H14A—C14—H14B | 109.5 |
C4—C5—H5B | 108.2 | C7—C14—H14C | 109.5 |
H5A—C5—H5B | 107.4 | H14A—C14—H14C | 109.5 |
C5—C6—C7 | 119.8 (4) | H14B—C14—H14C | 109.5 |
C5—C6—H6A | 107.4 | C7—C15—H15A | 109.5 |
C7—C6—H6A | 107.4 | C7—C15—H15B | 109.5 |
C5—C6—H6B | 107.4 | H15A—C15—H15B | 109.5 |
C7—C6—H6B | 107.4 | C7—C15—H15C | 109.5 |
H6A—C6—H6B | 106.9 | H15A—C15—H15C | 109.5 |
C14—C7—C15 | 106.9 (3) | H15B—C15—H15C | 109.5 |
C14—C7—C6 | 111.5 (3) | C10—C16—H16A | 109.5 |
C15—C7—C6 | 106.4 (3) | C10—C16—H16B | 109.5 |
C14—C7—C8 | 107.6 (3) | H16A—C16—H16B | 109.5 |
C15—C7—C8 | 112.7 (3) | C10—C16—H16C | 109.5 |
C6—C7—C8 | 111.7 (3) | H16A—C16—H16C | 109.5 |
C9—C8—C1 | 109.3 (3) | H16B—C16—H16C | 109.5 |
C9—C8—C7 | 112.1 (2) |
Experimental details
Crystal data | |
Chemical formula | C16H22Br2O |
Mr | 390.16 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 298 |
a, b, c (Å) | 6.7369 (1), 14.7635 (3), 16.3543 (3) |
V (Å3) | 1626.60 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 4.98 |
Crystal size (mm) | 0.80 × 0.65 × 0.25 |
Data collection | |
Diffractometer | Bruker APEXII CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.259, 0.746 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11891, 3330, 2939 |
Rint | 0.028 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.074, 1.06 |
No. of reflections | 3330 |
No. of parameters | 176 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.68, −0.37 |
Absolute structure | Flack (1983), 1397 Friedel pairs |
Absolute structure parameter | 0.021 (12) |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), WinGX (Farrugia, 2012).
Acknowledgements
The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.
References
Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chekroun, A., Jarid, A., Benharref, A. & Boutalib, A. (2000). J. Org. Chem. 65, 4431–4434. Web of Science CrossRef PubMed CAS Google Scholar
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358. CrossRef CAS Web of Science Google Scholar
Dakir, M., Auhmani, A., Ait Itto, M. Y., Mazoir, N., Akssira, M., Pierrot, M. & Benharref, A. (2004). Synth. Commun. 34, 2001–2008. Web of Science CrossRef CAS Google Scholar
Daoubi, M., Duran-Patron, R., Hmamouchi, M., Hernandez-Galan, R., Benharref, A. & Isidro, G. C. (2004). Pest Manag. Sci. 60, 927–932. Web of Science CrossRef PubMed CAS Google Scholar
El Jamili, H., Auhmani, A., Dakir, M., Lassaba, E., Benharref, A., Pierrot, M., Chiaroni, A. & Riche, C. (2002). Tetrahedron Lett. 43, 6645–6648. CAS Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Joseph, T. C. & Dev, S. (1968). Tetrahedron, 24, 3841–3859. CrossRef CAS Web of Science Google Scholar
Lassaba, E., Chekroun, A., Benharref, A., Chiaroni, A., Riche, C. & Lavergne, J.-P. (1997). Bull. Soc. Chim. Belg. 106, 281–288. CAS Google Scholar
Plattier, M. & Teiseire, P. (1974). Recherche, 19, 131–144. CAS Google Scholar
Sbai, F., Dakir, M., Auhmani, A., El Jamili, H., Akssira, M., Benharref, A., Kenz, A. & Pierrot, M. (2002). Acta Cryst. C58, o518–o520. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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The essential oil of the Atlas cedar (Cedrus atlantica) consist mainly (50%) of a bicyclic hydrocarbon called β-himachalene (Plattier & Teiseire(1974); Joseph & Dev (1968)). The reactivity of this sesquiterpene and its derivatives has been studied extensively by our team in order to prepare new products having biological proprieties. (Lassaba et al., 1997; Chekroun et al., 2000; El Jamili et al., 2002; Sbai et al., 2002; Dakir et al., 2004). Indeed, these compounds were tested, using the food poisoning technique, for their potential antifungal activity against the phytopathogen Botrytis cinerea (Daoubi et al., 2004). In a previous work (El Jamili et al., 2002), we have prepared, from β-himachalene, the (1S,3R,8R)-2,2-dibromo- 3,7,7,10- tetramethyltricyclo [6.4.0.01,3] dodec-9-ene, which is treated with N-bromosuccinimide and gave the title compound. The structure of this new product was determined by its single-crystal X-ray structure. The molecule is built up from two fused six-and seven- membered rings and an additional three-membered ring from the reaction with the carbene (Fig.1). The six-membered ring has an envelope conformation, as indicated by the total puckering amplitude QT = 0.433 (3) Å and spherical polar angle θ= 123.1 (4)° with ϕ = 181.6 (5)°, whereas the seven-membered ring display a screw boat conformation with QT = 1.1208 (4) Å, θ = 88.14 (2)°, ϕ2 = -49.94 (2)° and ϕ3 = -93.26 (5)° (Cremer & Pople, 1975). Owing to the presence of Br atoms, the absolute configuration could be fully confirmed, by refining the Flack parameter (Flack & Bernardinelli (2000)) as C1(S), C3(R) and C8(R).