(1S,3R,8R)-2,2-Dibromo-3,7,7,10-tetra-methyl-tricyclo-[6.4.0.0(1,3)]dodec-9-ene.

The title compound, C(16)H(24)Br(2), 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 two fused six- and seven-membered rings and an additional three-membered ring from the reaction of β-himachalene with dibromo-carbene. The six-membered ring shows a screw-boat conformation, whereas the seven-membered ring displays a boat conformation; the dihedral angle between the mean planes through the rings is 57.9 (4)°. The absolute structure was established unambiguously from anomalous dispersion effects.

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

C16H24Br2

M = 376.17

Orthorhombic,

a = 9.7464 (14) Å

b = 12.1633 (16) Å

c = 13.5352 (18) Å

V = 1604.6 (4) Å3

Z = 4

Mo Kα radiation

μ = 5.04 mm−1

T = 298 K

0.78 × 0.66 × 0.24 mm

Data collection

Bruker APEXII CCD diffractometer

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

17190 measured reflections

3254 independent reflections

2281 reflections with I > 2σ(I)

R int = 0.086

Refinement

R[F 2 > 2σ(F 2)] = 0.049

wR(F 2) = 0.132

S = 1.06

3254 reflections

167 parameters

H-atom parameters constrained

Δρmax = 0.85 e Å−3

Δρmin = −1.05 e Å−3

Absolute structure: Flack (1983 ▶), 1380 Friedel pairs

Flack parameter: 0.07 (2)

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT-Plus (Bruker, 2009 ▶); data reduction: SAINT-Plus; 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, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812032333/im2394sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812032333/im2394Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812032333/im2394Isup3.cml

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

C16H24Br2	F(000) = 760
Mr = 376.17	Dx = 1.557 Mg m−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 17190 reflections
a = 9.7464 (14) Å	θ = 2.6–26.4°
b = 12.1633 (16) Å	µ = 5.04 mm−1
c = 13.5352 (18) Å	T = 298 K
V = 1604.6 (4) Å3	Prism, colourless
Z = 4	0.78 × 0.66 × 0.24 mm

Bruker APEXII CCD diffractometer	3254 independent reflections
Radiation source: fine-focus sealed tube	2281 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.086
ω and φ scans	θmax = 26.4°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −12→12
Tmin = 0.259, Tmax = 0.746	k = −15→15
17190 measured reflections	l = −16→16

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)] = 0.049	H-atom parameters constrained
wR(F2) = 0.132	w = 1/[σ2(Fo2) + (0.0682P)2 + 0.6114P] where P = (Fo2 + 2Fc2)/3
S = 1.06	(Δ/σ)max < 0.001
3254 reflections	Δρmax = 0.85 e Å−3
167 parameters	Δρmin = −1.05 e Å−3
0 restraints	Absolute structure: Flack (1983), 1380 Friedel pairs
Primary atom site location: structure-invariant direct methods	Flack parameter: 0.07 (2)

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	0.3347 (7)	0.6855 (4)	0.2295 (4)	0.0321 (13)
C2	0.4162 (7)	0.7675 (5)	0.1685 (5)	0.0368 (15)
C3	0.3869 (8)	0.6562 (5)	0.1251 (5)	0.0413 (15)
C4	0.2801 (8)	0.6488 (6)	0.0455 (5)	0.0486 (19)
H4A	0.3251	0.6479	−0.0185	0.058*
H4B	0.2221	0.7135	0.0482	0.058*
C5	0.1901 (11)	0.5455 (7)	0.0554 (6)	0.067 (2)
H5A	0.2369	0.4842	0.0243	0.080*
H5B	0.1049	0.5575	0.0199	0.080*
C6	0.1559 (10)	0.5140 (6)	0.1633 (6)	0.062 (2)
H6A	0.2404	0.4906	0.1948	0.074*
H6B	0.0953	0.4507	0.1616	0.074*
C7	0.0886 (7)	0.6022 (6)	0.2302 (5)	0.0480 (17)
C8	0.1814 (6)	0.7070 (5)	0.2427 (4)	0.0340 (13)
H8	0.1550	0.7576	0.1897	0.041*
C9	0.1592 (8)	0.7681 (5)	0.3381 (5)	0.0457 (17)
H9	0.0743	0.8016	0.3471	0.055*
C10	0.2497 (7)	0.7784 (5)	0.4100 (5)	0.0424 (17)
C11	0.3862 (7)	0.7238 (5)	0.4053 (4)	0.0399 (16)
H11A	0.4029	0.6870	0.4678	0.048*
H11B	0.4561	0.7798	0.3974	0.048*
C12	0.4011 (8)	0.6409 (4)	0.3229 (4)	0.0349 (14)
H12A	0.3576	0.5723	0.3417	0.042*
H12B	0.4976	0.6265	0.3109	0.042*
C13	0.2240 (10)	0.8474 (8)	0.4997 (7)	0.075 (3)
H13A	0.1371	0.8839	0.4932	0.113*
H13B	0.2955	0.9013	0.5060	0.113*
H13C	0.2229	0.8014	0.5573	0.113*
C14	0.0598 (10)	0.5426 (7)	0.3284 (7)	0.072 (3)
H14A	0.0060	0.4779	0.3159	0.108*
H14B	0.0103	0.5907	0.3718	0.108*
H14C	0.1451	0.5219	0.3586	0.108*
C15	−0.0479 (10)	0.6373 (8)	0.1882 (9)	0.092 (3)
H15A	−0.0345	0.6672	0.1232	0.138*
H15B	−0.0880	0.6923	0.2301	0.138*
H15C	−0.1079	0.5749	0.1844	0.138*
C16	0.5021 (8)	0.5748 (6)	0.1134 (6)	0.058 (2)
H16A	0.5482	0.5876	0.0518	0.088*
H16B	0.4656	0.5015	0.1142	0.088*
H16C	0.5660	0.5834	0.1668	0.088*
Br1	0.33615 (9)	0.89924 (6)	0.11733 (6)	0.0589 (3)
Br2	0.60263 (7)	0.80174 (6)	0.20570 (6)	0.0556 (2)

	U11	U22	U33	U12	U13	U23
C1	0.037 (3)	0.027 (3)	0.033 (3)	0.000 (3)	−0.005 (3)	0.001 (2)
C2	0.039 (4)	0.036 (3)	0.035 (3)	−0.004 (3)	−0.003 (3)	0.006 (2)
C3	0.045 (4)	0.043 (3)	0.036 (3)	−0.005 (3)	0.003 (4)	−0.002 (3)
C4	0.060 (6)	0.056 (4)	0.030 (3)	−0.016 (4)	−0.007 (4)	−0.002 (3)
C5	0.081 (7)	0.074 (5)	0.046 (4)	−0.020 (5)	−0.010 (5)	−0.015 (4)
C6	0.071 (6)	0.056 (4)	0.058 (4)	−0.021 (4)	−0.011 (5)	−0.006 (4)
C7	0.038 (4)	0.058 (4)	0.048 (4)	−0.012 (4)	−0.003 (4)	0.004 (3)
C8	0.028 (4)	0.040 (3)	0.034 (3)	0.000 (3)	−0.004 (3)	0.003 (2)
C9	0.031 (4)	0.041 (3)	0.065 (4)	0.007 (3)	0.017 (4)	−0.008 (3)
C10	0.039 (4)	0.048 (4)	0.040 (4)	−0.012 (3)	0.007 (3)	−0.007 (3)
C11	0.038 (4)	0.052 (4)	0.030 (3)	−0.001 (3)	−0.007 (3)	−0.002 (2)
C12	0.036 (4)	0.033 (3)	0.036 (3)	0.002 (3)	−0.001 (3)	0.002 (2)
C13	0.067 (6)	0.089 (6)	0.070 (6)	−0.011 (5)	0.019 (5)	−0.045 (5)
C14	0.063 (6)	0.076 (5)	0.077 (6)	−0.025 (4)	−0.004 (5)	0.013 (4)
C15	0.051 (6)	0.099 (7)	0.127 (9)	−0.014 (5)	−0.034 (7)	0.009 (6)
C16	0.059 (5)	0.057 (4)	0.060 (5)	0.009 (4)	0.023 (4)	−0.012 (4)
Br1	0.0687 (6)	0.0419 (3)	0.0662 (5)	−0.0017 (4)	−0.0037 (4)	0.0198 (3)
Br2	0.0369 (4)	0.0639 (4)	0.0661 (5)	−0.0149 (3)	0.0047 (4)	0.0019 (4)

C1—C2	1.519 (8)	C8—H8	0.9800
C1—C12	1.520 (8)	C9—C10	1.319 (10)
C1—C8	1.527 (9)	C9—H9	0.9300
C1—C3	1.545 (9)	C10—C11	1.488 (10)
C2—C3	1.503 (8)	C10—C13	1.497 (9)
C2—Br1	1.913 (6)	C11—C12	1.510 (8)
C2—Br2	1.931 (7)	C11—H11A	0.9700
C3—C4	1.501 (10)	C11—H11B	0.9700
C3—C16	1.505 (10)	C12—H12A	0.9700
C4—C5	1.539 (11)	C12—H12B	0.9700
C4—H4A	0.9700	C13—H13A	0.9600
C4—H4B	0.9700	C13—H13B	0.9600
C5—C6	1.546 (12)	C13—H13C	0.9600
C5—H5A	0.9700	C14—H14A	0.9600
C5—H5B	0.9700	C14—H14B	0.9600
C6—C7	1.550 (11)	C14—H14C	0.9600
C6—H6A	0.9700	C15—H15A	0.9600
C6—H6B	0.9700	C15—H15B	0.9600
C7—C15	1.508 (12)	C15—H15C	0.9600
C7—C14	1.539 (11)	C16—H16A	0.9600
C7—C8	1.573 (9)	C16—H16B	0.9600
C8—C9	1.506 (9)	C16—H16C	0.9600
C2—C1—C12	117.6 (6)	C9—C8—H8	106.2
C2—C1—C8	117.5 (5)	C1—C8—H8	106.2
C12—C1—C8	112.4 (5)	C7—C8—H8	106.2
C2—C1—C3	58.8 (4)	C10—C9—C8	125.7 (6)
C12—C1—C3	122.6 (5)	C10—C9—H9	117.2
C8—C1—C3	118.0 (5)	C8—C9—H9	117.2
C3—C2—C1	61.5 (4)	C9—C10—C11	121.6 (6)
C3—C2—Br1	122.4 (5)	C9—C10—C13	122.6 (7)
C1—C2—Br1	122.2 (5)	C11—C10—C13	115.7 (7)
C3—C2—Br2	118.4 (5)	C10—C11—C12	114.6 (6)
C1—C2—Br2	119.5 (4)	C10—C11—H11A	108.6
Br1—C2—Br2	107.3 (3)	C12—C11—H11A	108.6
C4—C3—C2	117.8 (6)	C10—C11—H11B	108.6
C4—C3—C16	113.8 (6)	C12—C11—H11B	108.6
C2—C3—C16	119.4 (7)	H11A—C11—H11B	107.6
C4—C3—C1	116.3 (6)	C11—C12—C1	109.6 (5)
C2—C3—C1	59.8 (4)	C11—C12—H12A	109.8
C16—C3—C1	119.6 (6)	C1—C12—H12A	109.8
C3—C4—C5	112.4 (6)	C11—C12—H12B	109.8
C3—C4—H4A	109.1	C1—C12—H12B	109.8
C5—C4—H4A	109.1	H12A—C12—H12B	108.2
C3—C4—H4B	109.1	C10—C13—H13A	109.5
C5—C4—H4B	109.1	C10—C13—H13B	109.5
H4A—C4—H4B	107.8	H13A—C13—H13B	109.5
C4—C5—C6	114.1 (6)	C10—C13—H13C	109.5
C4—C5—H5A	108.7	H13A—C13—H13C	109.5
C6—C5—H5A	108.7	H13B—C13—H13C	109.5
C4—C5—H5B	108.7	C7—C14—H14A	109.5
C6—C5—H5B	108.7	C7—C14—H14B	109.5
H5A—C5—H5B	107.6	H14A—C14—H14B	109.5
C5—C6—C7	118.2 (7)	C7—C14—H14C	109.5
C5—C6—H6A	107.8	H14A—C14—H14C	109.5
C7—C6—H6A	107.8	H14B—C14—H14C	109.5
C5—C6—H6B	107.8	C7—C15—H15A	109.5
C7—C6—H6B	107.8	C7—C15—H15B	109.5
H6A—C6—H6B	107.1	H15A—C15—H15B	109.5
C15—C7—C14	107.4 (8)	C7—C15—H15C	109.5
C15—C7—C6	110.4 (7)	H15A—C15—H15C	109.5
C14—C7—C6	104.8 (6)	H15B—C15—H15C	109.5
C15—C7—C8	108.6 (6)	C3—C16—H16A	109.5
C14—C7—C8	113.2 (6)	C3—C16—H16B	109.5
C6—C7—C8	112.3 (6)	H16A—C16—H16B	109.5
C9—C8—C1	109.0 (5)	C3—C16—H16C	109.5
C9—C8—C7	114.2 (5)	H16A—C16—H16C	109.5
C1—C8—C7	114.3 (5)	H16B—C16—H16C	109.5