Absolute configuration of vouaca-pen-5α-ol.

The title compound, C(20)H(30)O(2), {systematic name: (4aR,6aS,7R,11aS,11bR)-4,4,7,11b-tetra-methyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodeca-hydro-phenanthro[3,2-b]furan-4a-ol}, is a cas-sane furan-oditerpene which was isolated from the roots of Caesalpinia pulcherrima. The absolute configurations at positions 4a, 6a, 7, 11a and 11b are R, S, R, S and R, respectively. The mol-ecule has four-fused rings consisting of three cyclo-hexane rings and one furan ring. The three cyclo-hexane rings are trans-fused. Two cyclo-hexane rings are in chair conformations, while the third is in an envelope conformation. In the crystal structure, the mol-ecules are linked by inter-molecular O-H⋯O hydrogen bonds into a zigzag chain along the a axis. A short O⋯O contact [3.0398 (14) Å] is also present.

Related literature

For ring conformations, see: Cremer & Pople (1975 ▶). For bond-length data, see: Allen et al. (1987 ▶). For background to cassane furan­oditerpenes and their biological activities, see: Che et al. (1986 ▶); Jiang et al. (2001 ▶); McPherson et al. (1986 ▶); Promsawan et al. (2003 ▶); Ragasa et al. (2002 ▶); Smitinand & Larson (2001 ▶); Tewtrakul et al. (2003 ▶). For related structures, see: Fun et al. (2010 ▶); Jiang et al. (2001 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C20H30O2

M = 302.44

Orthorhombic,

a = 6.7367 (2) Å

b = 12.7818 (3) Å

c = 19.3472 (5) Å

V = 1665.93 (8) Å3

Z = 4

Cu Kα radiation

μ = 0.58 mm−1

T = 100 K

0.29 × 0.22 × 0.17 mm

Data collection

Bruker APEX DUO CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T min = 0.851, T max = 0.908

30751 measured reflections

2880 independent reflections

2856 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.027

wR(F 2) = 0.088

S = 1.16

2880 reflections

207 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.21 e Å−3

Δρmin = −0.25 e Å−3

Absolute structure: Flack (1983 ▶), 1202 Friedel pairs

Flack parameter: 0.0 (2)

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810029557/is2581sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810029557/is2581Isup2.hkl

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

C20H30O2	Dx = 1.206 Mg m−3
Mr = 302.44	Melting point = 371–373 K
Orthorhombic, P212121	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2ac 2ab	Cell parameters from 2880 reflections
a = 6.7367 (2) Å	θ = 4.6–66.0°
b = 12.7818 (3) Å	µ = 0.58 mm−1
c = 19.3472 (5) Å	T = 100 K
V = 1665.93 (8) Å3	Block, colorless
Z = 4	0.29 × 0.22 × 0.17 mm
F(000) = 664

Bruker APEX DUO CCD area-detector diffractometer	2880 independent reflections
Radiation source: sealed tube	2856 reflections with I > 2σ(I)
graphite	Rint = 0.028
φ and ω scans	θmax = 66.0°, θmin = 4.6°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −7→7
Tmin = 0.851, Tmax = 0.908	k = −15→15
30751 measured reflections	l = −22→22

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)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.088	w = 1/[σ2(Fo2) + (0.0545P)2 + 0.2119P] where P = (Fo2 + 2Fc2)/3
S = 1.16	(Δ/σ)max = 0.001
2880 reflections	Δρmax = 0.21 e Å−3
207 parameters	Δρmin = −0.25 e Å−3
0 restraints	Absolute structure: Flack (1983), 1202 Friedel pairs
Primary atom site location: structure-invariant direct methods	Flack parameter: 0.0 (2)

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
O1	1.03886 (16)	0.52792 (8)	0.07346 (5)	0.0334 (2)
O2	0.57276 (13)	0.96871 (7)	0.08320 (5)	0.0258 (2)
C1	0.9773 (2)	0.93648 (11)	0.02533 (7)	0.0275 (3)
H1A	1.0886	0.8924	0.0127	0.033*
H1B	0.8677	0.9195	−0.0052	0.033*
C2	1.0353 (2)	1.05118 (11)	0.01446 (8)	0.0328 (3)
H2A	1.1552	1.0662	0.0404	0.039*
H2B	1.0636	1.0628	−0.0341	0.039*
C3	0.8709 (2)	1.12537 (11)	0.03751 (8)	0.0304 (3)
H3A	0.7575	1.1163	0.0072	0.036*
H3B	0.9172	1.1968	0.0323	0.036*
C4	0.8027 (2)	1.10897 (11)	0.11288 (7)	0.0273 (3)
C5	0.7496 (2)	0.98994 (10)	0.12352 (7)	0.0235 (3)
C6	0.6857 (2)	0.96538 (11)	0.19790 (7)	0.0265 (3)
H6A	0.7961	0.9786	0.2289	0.032*
H6B	0.5779	1.0116	0.2109	0.032*
C7	0.6185 (2)	0.85208 (11)	0.20597 (7)	0.0264 (3)
H7A	0.4932	0.8434	0.1819	0.032*
H7B	0.5948	0.8385	0.2546	0.032*
C8	0.76551 (19)	0.77021 (11)	0.17865 (6)	0.0235 (3)
H8A	0.8849	0.7742	0.2075	0.028*
C9	0.8275 (2)	0.79830 (10)	0.10381 (6)	0.0231 (3)
H9A	0.7059	0.7988	0.0760	0.028*
C10	0.91614 (19)	0.91155 (10)	0.10034 (7)	0.0233 (3)
C11	0.9692 (2)	0.71734 (11)	0.07021 (7)	0.0295 (3)
H11A	0.9471	0.7157	0.0207	0.035*
H11B	1.1058	0.7381	0.0783	0.035*
C12	0.9355 (2)	0.61239 (11)	0.09923 (7)	0.0274 (3)
C13	0.8133 (2)	0.58241 (11)	0.15075 (7)	0.0261 (3)
C14	0.6792 (2)	0.65857 (11)	0.18679 (6)	0.0249 (3)
H14A	0.6797	0.6413	0.2362	0.030*
C15	0.8399 (2)	0.47142 (12)	0.15815 (7)	0.0316 (3)
H15A	0.7751	0.4278	0.1893	0.038*
C16	0.9764 (3)	0.44313 (11)	0.11136 (7)	0.0349 (3)
H16A	1.0227	0.3752	0.1053	0.042*
C17	0.4653 (2)	0.64563 (12)	0.16019 (7)	0.0301 (3)
H17A	0.4312	0.5727	0.1595	0.045*
H17B	0.4555	0.6738	0.1143	0.045*
H17C	0.3758	0.6824	0.1902	0.045*
C18	0.6175 (2)	1.17717 (12)	0.12459 (8)	0.0370 (4)
H18A	0.6459	1.2480	0.1113	0.056*
H18B	0.5815	1.1753	0.1726	0.056*
H18C	0.5097	1.1508	0.0972	0.056*
C19	0.9636 (3)	1.14968 (12)	0.16241 (8)	0.0376 (4)
H19A	0.9689	1.2246	0.1600	0.056*
H19B	1.0900	1.1211	0.1494	0.056*
H19C	0.9324	1.1287	0.2088	0.056*
C20	1.1033 (2)	0.91693 (12)	0.14665 (8)	0.0308 (3)
H20A	1.1679	0.8500	0.1470	0.046*
H20B	1.0654	0.9354	0.1929	0.046*
H20C	1.1928	0.9688	0.1288	0.046*
H1O2	0.602 (3)	0.9757 (14)	0.0405 (10)	0.038 (5)*

	U11	U22	U33	U12	U13	U23
O1	0.0389 (6)	0.0318 (5)	0.0295 (5)	0.0068 (5)	0.0075 (4)	0.0007 (4)
O2	0.0193 (5)	0.0341 (5)	0.0239 (5)	−0.0007 (4)	−0.0017 (4)	0.0012 (4)
C1	0.0247 (7)	0.0333 (7)	0.0245 (7)	−0.0005 (6)	0.0057 (5)	0.0007 (5)
C2	0.0313 (8)	0.0389 (8)	0.0283 (7)	−0.0058 (6)	0.0075 (6)	0.0034 (6)
C3	0.0345 (8)	0.0288 (7)	0.0278 (7)	−0.0061 (6)	0.0020 (6)	0.0016 (5)
C4	0.0290 (7)	0.0296 (7)	0.0232 (7)	−0.0039 (6)	0.0000 (6)	−0.0007 (5)
C5	0.0192 (6)	0.0302 (7)	0.0212 (6)	−0.0002 (5)	0.0002 (5)	0.0000 (5)
C6	0.0258 (6)	0.0328 (7)	0.0210 (6)	0.0017 (6)	0.0025 (5)	−0.0028 (5)
C7	0.0242 (6)	0.0342 (7)	0.0207 (6)	0.0013 (6)	0.0058 (5)	0.0015 (5)
C8	0.0195 (6)	0.0324 (7)	0.0184 (6)	0.0010 (6)	−0.0001 (5)	0.0016 (5)
C9	0.0192 (6)	0.0306 (7)	0.0196 (6)	0.0015 (5)	0.0015 (5)	0.0009 (5)
C10	0.0184 (6)	0.0299 (7)	0.0216 (6)	−0.0009 (5)	0.0005 (5)	0.0004 (5)
C11	0.0285 (7)	0.0334 (7)	0.0267 (7)	0.0032 (6)	0.0075 (6)	0.0019 (6)
C12	0.0284 (7)	0.0314 (7)	0.0224 (7)	0.0064 (6)	0.0001 (5)	−0.0029 (5)
C13	0.0265 (7)	0.0306 (7)	0.0213 (6)	−0.0006 (5)	−0.0032 (5)	0.0011 (5)
C14	0.0248 (6)	0.0330 (7)	0.0169 (6)	−0.0005 (6)	0.0019 (5)	0.0020 (5)
C15	0.0380 (8)	0.0323 (7)	0.0244 (7)	−0.0020 (7)	−0.0005 (6)	0.0029 (6)
C16	0.0480 (9)	0.0277 (7)	0.0290 (7)	0.0059 (7)	0.0004 (7)	0.0022 (6)
C17	0.0267 (7)	0.0376 (7)	0.0260 (7)	−0.0036 (6)	0.0012 (6)	0.0025 (6)
C18	0.0438 (9)	0.0311 (7)	0.0363 (8)	0.0042 (7)	0.0063 (7)	−0.0006 (6)
C19	0.0437 (9)	0.0375 (8)	0.0315 (8)	−0.0123 (7)	−0.0046 (7)	−0.0035 (6)
C20	0.0191 (6)	0.0412 (8)	0.0321 (7)	−0.0023 (6)	−0.0034 (6)	0.0025 (6)

O1—C16	1.3745 (17)	C9—C11	1.5507 (18)
O1—C12	1.3780 (16)	C9—C10	1.5673 (18)
O2—C5	1.4494 (16)	C9—H9A	0.9800
O2—H1O2	0.85 (2)	C10—C20	1.5486 (18)
C1—C2	1.5319 (19)	C11—C12	1.4719 (19)
C1—C10	1.5417 (18)	C11—H11A	0.9700
C1—H1A	0.9700	C11—H11B	0.9700
C1—H1B	0.9700	C12—C13	1.348 (2)
C2—C3	1.525 (2)	C13—C15	1.437 (2)
C2—H2A	0.9700	C13—C14	1.5001 (19)
C2—H2B	0.9700	C14—C17	1.5388 (19)
C3—C4	1.5432 (19)	C14—H14A	0.9800
C3—H3A	0.9700	C15—C16	1.340 (2)
C3—H3B	0.9700	C15—H15A	0.9300
C4—C19	1.538 (2)	C16—H16A	0.9300
C4—C18	1.538 (2)	C17—H17A	0.9600
C4—C5	1.5764 (19)	C17—H17B	0.9600
C5—C6	1.5345 (18)	C17—H17C	0.9600
C5—C10	1.5699 (18)	C18—H18A	0.9600
C6—C7	1.525 (2)	C18—H18B	0.9600
C6—H6A	0.9700	C18—H18C	0.9600
C6—H6B	0.9700	C19—H19A	0.9600
C7—C8	1.5347 (18)	C19—H19B	0.9600
C7—H7A	0.9700	C19—H19C	0.9600
C7—H7B	0.9700	C20—H20A	0.9600
C8—C14	1.5489 (19)	C20—H20B	0.9600
C8—C9	1.5493 (17)	C20—H20C	0.9600
C8—H8A	0.9800
C16—O1—C12	105.67 (11)	C10—C9—H9A	106.8
C5—O2—H1O2	108.0 (13)	C1—C10—C20	108.54 (11)
C2—C1—C10	113.28 (11)	C1—C10—C9	109.45 (10)
C2—C1—H1A	108.9	C20—C10—C9	109.06 (11)
C10—C1—H1A	108.9	C1—C10—C5	109.14 (10)
C2—C1—H1B	108.9	C20—C10—C5	112.86 (11)
C10—C1—H1B	108.9	C9—C10—C5	107.75 (10)
H1A—C1—H1B	107.7	C12—C11—C9	110.69 (11)
C3—C2—C1	111.68 (11)	C12—C11—H11A	109.5
C3—C2—H2A	109.3	C9—C11—H11A	109.5
C1—C2—H2A	109.3	C12—C11—H11B	109.5
C3—C2—H2B	109.3	C9—C11—H11B	109.5
C1—C2—H2B	109.3	H11A—C11—H11B	108.1
H2A—C2—H2B	107.9	C13—C12—O1	110.69 (12)
C2—C3—C4	114.09 (12)	C13—C12—C11	129.43 (12)
C2—C3—H3A	108.7	O1—C12—C11	119.88 (12)
C4—C3—H3A	108.7	C12—C13—C15	106.14 (13)
C2—C3—H3B	108.7	C12—C13—C14	121.80 (12)
C4—C3—H3B	108.7	C15—C13—C14	132.02 (13)
H3A—C3—H3B	107.6	C13—C14—C17	109.80 (11)
C19—C4—C18	106.74 (12)	C13—C14—C8	108.93 (11)
C19—C4—C3	109.45 (12)	C17—C14—C8	114.61 (11)
C18—C4—C3	107.68 (12)	C13—C14—H14A	107.8
C19—C4—C5	113.90 (11)	C17—C14—H14A	107.8
C18—C4—C5	110.10 (11)	C8—C14—H14A	107.8
C3—C4—C5	108.79 (11)	C16—C15—C13	106.54 (13)
O2—C5—C6	103.66 (10)	C16—C15—H15A	126.7
O2—C5—C10	108.31 (10)	C13—C15—H15A	126.7
C6—C5—C10	109.74 (10)	C15—C16—O1	110.95 (13)
O2—C5—C4	107.27 (10)	C15—C16—H16A	124.5
C6—C5—C4	112.55 (11)	O1—C16—H16A	124.5
C10—C5—C4	114.61 (10)	C14—C17—H17A	109.5
C7—C6—C5	111.92 (11)	C14—C17—H17B	109.5
C7—C6—H6A	109.2	H17A—C17—H17B	109.5
C5—C6—H6A	109.2	C14—C17—H17C	109.5
C7—C6—H6B	109.2	H17A—C17—H17C	109.5
C5—C6—H6B	109.2	H17B—C17—H17C	109.5
H6A—C6—H6B	107.9	C4—C18—H18A	109.5
C6—C7—C8	114.87 (11)	C4—C18—H18B	109.5
C6—C7—H7A	108.5	H18A—C18—H18B	109.5
C8—C7—H7A	108.5	C4—C18—H18C	109.5
C6—C7—H7B	108.5	H18A—C18—H18C	109.5
C8—C7—H7B	108.5	H18B—C18—H18C	109.5
H7A—C7—H7B	107.5	C4—C19—H19A	109.5
C7—C8—C14	110.54 (11)	C4—C19—H19B	109.5
C7—C8—C9	109.74 (11)	H19A—C19—H19B	109.5
C14—C8—C9	114.19 (11)	C4—C19—H19C	109.5
C7—C8—H8A	107.4	H19A—C19—H19C	109.5
C14—C8—H8A	107.4	H19B—C19—H19C	109.5
C9—C8—H8A	107.4	C10—C20—H20A	109.5
C8—C9—C11	113.77 (11)	C10—C20—H20B	109.5
C8—C9—C10	110.90 (10)	H20A—C20—H20B	109.5
C11—C9—C10	111.33 (10)	C10—C20—H20C	109.5
C8—C9—H9A	106.8	H20A—C20—H20C	109.5
C11—C9—H9A	106.8	H20B—C20—H20C	109.5
C10—C1—C2—C3	−55.24 (17)	C11—C9—C10—C5	170.45 (11)
C1—C2—C3—C4	55.00 (16)	O2—C5—C10—C1	66.93 (13)
C2—C3—C4—C19	72.73 (15)	C6—C5—C10—C1	179.45 (11)
C2—C3—C4—C18	−171.60 (12)	C4—C5—C10—C1	−52.77 (14)
C2—C3—C4—C5	−52.30 (15)	O2—C5—C10—C20	−172.30 (10)
C19—C4—C5—O2	169.30 (11)	C6—C5—C10—C20	−59.78 (14)
C18—C4—C5—O2	49.46 (14)	C4—C5—C10—C20	68.00 (14)
C3—C4—C5—O2	−68.32 (13)	O2—C5—C10—C9	−51.83 (13)
C19—C4—C5—C6	55.92 (15)	C6—C5—C10—C9	60.69 (13)
C18—C4—C5—C6	−63.92 (15)	C4—C5—C10—C9	−171.54 (10)
C3—C4—C5—C6	178.30 (11)	C8—C9—C11—C12	28.58 (16)
C19—C4—C5—C10	−70.41 (15)	C10—C9—C11—C12	154.78 (11)
C18—C4—C5—C10	169.75 (11)	C16—O1—C12—C13	−0.18 (16)
C3—C4—C5—C10	51.97 (14)	C16—O1—C12—C11	179.32 (13)
O2—C5—C6—C7	59.70 (13)	C9—C11—C12—C13	−4.3 (2)
C10—C5—C6—C7	−55.82 (14)	C9—C11—C12—O1	176.33 (12)
C4—C5—C6—C7	175.28 (11)	O1—C12—C13—C15	−0.23 (16)
C5—C6—C7—C8	51.72 (15)	C11—C12—C13—C15	−179.67 (15)
C6—C7—C8—C14	−177.79 (11)	O1—C12—C13—C14	−178.36 (11)
C6—C7—C8—C9	−50.97 (15)	C11—C12—C13—C14	2.2 (2)
C7—C8—C9—C11	−177.42 (11)	C12—C13—C14—C17	102.74 (15)
C14—C8—C9—C11	−52.68 (15)	C15—C13—C14—C17	−74.84 (18)
C7—C8—C9—C10	56.15 (14)	C12—C13—C14—C8	−23.52 (17)
C14—C8—C9—C10	−179.10 (10)	C15—C13—C14—C8	158.90 (14)
C2—C1—C10—C20	−70.08 (15)	C7—C8—C14—C13	172.14 (10)
C2—C1—C10—C9	171.00 (11)	C9—C8—C14—C13	47.82 (14)
C2—C1—C10—C5	53.30 (15)	C7—C8—C14—C17	48.70 (14)
C8—C9—C10—C1	179.65 (11)	C9—C8—C14—C17	−75.62 (14)
C11—C9—C10—C1	51.88 (14)	C12—C13—C15—C16	0.56 (17)
C8—C9—C10—C20	61.04 (13)	C14—C13—C15—C16	178.42 (14)
C11—C9—C10—C20	−66.72 (13)	C13—C15—C16—O1	−0.70 (17)
C8—C9—C10—C5	−61.79 (13)	C12—O1—C16—C15	0.56 (17)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1O2···O1i	0.854 (19)	2.246 (19)	3.0398 (14)	154.7 (18)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H1O2⋯O1i	0.854 (19)	2.246 (19)	3.0398 (14)	154.7 (18)

Symmetry code: (i) .