(1S,3R,8R)-2,2-Dibromo-3,7,7,10-tetra-methyltricyclo-[6.4.0.0(1,3)]dodec-9-en-11-one.

The title compound, C16H22Br2O, was synthesized from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings and an additional three-membered ring from the reaction of himachalene with dibromo-carbene. The six-membered ring has an envelope conformation, 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 conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C16H22Br2O

M = 390.16

Orthorhombic,

a = 6.7369 (1) Å

b = 14.7635 (3) Å

c = 16.3543 (3) Å

V = 1626.60 (5) Å3

Z = 4

Mo Kα radiation

μ = 4.98 mm−1

T = 298 K

0.80 × 0.65 × 0.25 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ▶) T min = 0.259, T max = 0.746

11891 measured reflections

3330 independent reflections

2939 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.030

wR(F 2) = 0.074

S = 1.06

3330 reflections

176 parameters

H-atom parameters constrained

Δρmax = 0.68 e Å−3

Δρmin = −0.37 e Å−3

Absolute structure: Flack (1983) ▶, 1397 Friedel pairs

Flack parameter: 0.021 (12)

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: 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 ▶).

Click here for additional data file.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812046089/go2074sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812046089/go2074Isup2.hkl

Click here for additional data file.

Supplementary material file. DOI: 10.1107/S1600536812046089/go2074Isup3.cml

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

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	Flack parameter: 0.021 (12)

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)