(1S,3R,8R)-2,2-Dibromo-3,7,7,10-tetra­methyl­tricyclo­[6.4.0.01,3]dodec-9-ene

Benharref, A.; El Ammari, L.; Lassaba, E.; Ourhriss, N.; Berraho, M.

doi:10.1107/S1600536812032333

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 68| Part 8| August 2012| Page o2502

https://doi.org/10.1107/S1600536812032333

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(1S,3R,8R)-2,2-Dibromo-3,7,7,10-tetramethyltricyclo[6.4.0.0^1,3]dodec-9-ene

Ahmed Benharref,^a Lahcen El Ammari,^b Essêdiya Lassaba,^a ^* Najia Ourhriss ^a and Moha Berraho ^a

^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

(Received 11 July 2012; accepted 16 July 2012; online 21 July 2012)

The title compound, C₁₆H₂₄Br₂, 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 two fused six- and seven-membered rings and an additional three-membered ring from the reaction of β-himachalene with dibromocarbene. 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_r = 376.17
Orthorhombic, P 2₁ 2₁ 2₁
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[F² > 2σ(F²)] = 0.049
wR(F²) = 0.132
S = 1.06
3254 reflections
167 parameters
H-atom parameters constrained
Δρ_max = 0.85 e Å⁻³
Δρ_min = −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 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536812032333/im2394sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812032333/im2394Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536812032333/im2394Isup3.cml

checkCIF report

Comment top

The bicyclic sesquiterpene β-himachalene is the main constituent of the essential oil of the Atlas cedar (Cedrus atlantica) (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 phytopathogen Botrytis cinerea (Daoubi et al., 2004). Thus the action of one equivalent of dibromocarbene, generated in situ from bromoform in the presence of sodium hydroxide as base and n-benzyltriethylammonium chloride as catalyst, on β-himachalene produces the title compound (I) with a yield of 22%. The structure of this new product was determined by its single-crystal X-ray structure analysis. 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 a screw boat conformation, as indicated by the total puckering amplitude QT = 0.485 (19) Å and spherical polar angle θ = 128.1 (11)° with φ = 155.7 (14)°, whereas the seven-membered ring displays a boat conformation with QT = 1.1497 (1) Å, θ = 88.51 (5)°, φ2 = 311.8 (5)° and φ3 = 238.26 (19)° (Cremer & Pople, 1975). Owing to the presence of Br atoms, the absolute configuration could be fully confirmed, by refining the Flack parameter (Flack, 1983) as C1(S), C3(R) and C8(R).

Related literature top

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 top

A solution containing 5 g (24 mmol) of β-himachalene and 3 ml (37 mmol) of CHBr₃ in 30 ml of dichloromethane was added in dropwise fashion at 0°C over 30 min to 1,5 g (37 mmol) of pulverized sodium hydroxide and 50 mg of N– benzyltriethylammonium chloride placed in a 100 ml three – necked flask. After stirring at room temperature for 2 h, the mixture was filtered on celite and concentrated in vacuum. The residue obtained was chromatographed on silica gel using hexane as eluting agent to give 2 g (5,3 mmol) of (1S,3R,8R)-2,2-Dibromo-3,7,7,10-tetramethyl-tricyclo [6.4.0.0^1,3]dodec-9-ene with a yield of 22%. The title compound was recrystallized from pentane.

Structure description top

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).

Computing details top

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

Figures top

Fig. 1. : Molecular structure of the title compound with displacement ellipsoids drawn at the 30% probability. level. H atoms are represented as small spheres of arbitrary radii.

(1S,3R,8R)-2,2-Dibromo-3,7,7,10- tetramethyltricyclo[6.4.0.0^1,3]dodec-9-ene top

Crystal data top

C₁₆H₂₄Br₂	F(000) = 760
M_r = 376.17	D_x = 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

Data collection top

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

Refinement top

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(F_o²) + (0.0682P)² + 0.6114P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
3254 reflections	Δρ_max = 0.85 e Å⁻³
167 parameters	Δρ_min = −1.05 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1380 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.07 (2)

Crystal data top

C₁₆H₂₄Br₂	V = 1604.6 (4) Å³
M_r = 376.17	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 9.7464 (14) Å	µ = 5.04 mm⁻¹
b = 12.1633 (16) Å	T = 298 K
c = 13.5352 (18) Å	0.78 × 0.66 × 0.24 mm

Data collection top

Bruker APEXII CCD diffractometer	3254 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	2281 reflections with I > 2σ(I)
T_min = 0.259, T_max = 0.746	R_int = 0.086
17190 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	H-atom parameters constrained
wR(F²) = 0.132	Δρ_max = 0.85 e Å⁻³
S = 1.06	Δρ_min = −1.05 e Å⁻³
3254 reflections	Absolute structure: Flack (1983), 1380 Friedel pairs
167 parameters	Absolute structure parameter: 0.07 (2)
0 restraints

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
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)

Atomic displacement parameters (Å²) top

	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)

Geometric parameters (Å, º) top

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

Experimental details

Crystal data
Chemical formula	C₁₆H₂₄Br₂
M_r	376.17
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	298
a, b, c (Å)	9.7464 (14), 12.1633 (16), 13.5352 (18)
V (Å³)	1604.6 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	5.04
Crystal size (mm)	0.78 × 0.66 × 0.24

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.259, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	17190, 3254, 2281
R_int	0.086
(sin θ/λ)_max (Å⁻¹)	0.625

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.132, 1.06
No. of reflections	3254
No. of parameters	167
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.85, −1.05
Absolute structure	Flack (1983), 1380 Friedel pairs
Absolute structure parameter	0.07 (2)

Computer programs: APEX2 (Bruker, 2009), SAINT-Plus (Bruker, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

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