(1RS,2RS,3SR,5RS,7RS)-2,5-Dichloro-8-oxabicyclo­[5.1.0]octan-3-ol

Abstract

In the title compound, C₇H₁₀Cl₂O₂, the seven-membered ring displays a chair conformation. In the crystal, the hy­droxy H atom is equally disordered over two orientations, and links with an adjacent mol­ecule via an O—H⋯O hydrogen bond in both cases. Weak inter­molecular C—H⋯O hydrogen bonding is also a feature of the crystal structure.

Related literature

For background to syn-bis-epoxides, see: Balcı (1981 ▶); Akbulut et al. (1987 ▶); Menzek & Balcı (1993 ▶); Saraçoğlu et al. (1999 ▶). For background to unsaturated bicyclic endopexide, see: Menzek et al. (2005 ▶). For background to epoxide and bis-epoxide, see: Şengül et al. (2008 ▶).

Experimental

Crystal data

• C₇H₁₀Cl₂O₂

• M _r = 197.05

• Orthorhombic,

• a = 21.9202 (5) Å

• b = 9.9343 (3) Å

• c = 8.1005 (2) Å

• V = 1763.98 (8) ų

• Z = 8

• Mo Kα radiation

• μ = 0.68 mm⁻¹

• T = 294 K

• 0.32 × 0.20 × 0.15 mm

Data collection

• Rigaku R-AXIS RAPID-S diffractometer

• Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.845, T _max = 0.900

• 32813 measured reflections

• 1801 independent reflections

• 1267 reflections with I > 2σ(I)

• R _int = 0.110

Refinement

• R[F ² > 2σ(F ²)] = 0.088

• wR(F ²) = 0.190

• S = 1.18

• 1801 reflections

• 115 parameters

• 2 restraints

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.28 e Å⁻³

• Δρ_min = −0.34 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯O2i	0.83 (11)	1.96 (11)	2.746 (7)	159 (12)
O2—H2B⋯O2ii	0.85	1.84	2.692 (8)	174
C2—H21⋯O1iii	0.97	2.43	3.398 (7)	172

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

Comment

Unsaturated bicyclic endopexides are important compounds for versatile chemical transformations in organic chemistry. In these endoperoxides, diradicals formed by thermal cleavage of the weak O-O bonds react to give the syn-bis-epoxides (Balcı, 1981; Akbulut et al., 1987; Menzek & Balcı, 1993; Saraçoğlu et al., 1999).

Unsaturated bicyclic endopexide, (1), (Scheme 1) was synthesized by the literature method (Menzek et al., 2005). Reaction of endoperoxide, (1), by heating at 453 (5) K gave a mixture of products (Scheme 1). The title compound, (2), was isolated from these mixtures. The other products were not identified. According to the NMR data of dichloride, (2), it was not easy to establish the exact configuration of the molecule. Therefore, the exact structure of dichloride, (2), was determined by X-ray single crystal analysis.

To rationalize the formation of dichloride, (2), we propose the following reaction mechanism as favourable mechanism (Scheme 1). Bis-epoxide, (3), is produced via diradicals formed by thermal cleavage of the weak O-O bonds. HCl formed by elimination from reaction products such as (3) can attack bis-epoxide, (3), to give intermediate (4). Cl^- can attack intermediate (4) to give dichloride, (2), as a nucleophile. An epoxide or bis-epoxide ring (Şengül et al., 2008) may be opened by as a nucleophile.

In the title compound, the seven-membered ring A (C1-C7) is, of course, not planar. The planar moieties B (O1/C1/C7), C (C3-C5), D (C2/C3/C5/C6) and E (C1/C2/C6/C7) are oriented at dihedral angles of B/C = 68.75 (46)°, B/D = 13.84 (28)°, B/E = 74.48 (32)°, C/D = 54.91 (42)°, C/E = 6.00 (42)° and D/E = 60.65 (30)°.

In the crystal, intermolecular O—H···O and C—H···O hydrogen bonds link the molecules into a three-dimensional network (Table 1 and Fig. 2).

Experimental

For the preparation of the title compound, a mixture of endoproxide (0.5 g, 2.6 mmol) and benzene (5 ml) was placed into a test tube, sealed under vacuum and heated at 453 (5) K for 3 d. After cooling to room temperature, the solvent was evaporated. The residue was submitted to column chromatography (silica gel, 90 g) with AcOEt/hexane (1:6) as eluant. Dichloride (yield: 0.056 g, 9%, m. p. 366-368 K) and a mixture of unidentified products were obtained. Dichloride was crystallized from ethyl acetate/hexane (1:1) as colorless block crystals.

Refinement

H1, H7, H21, H22 and H41, H42 atoms were positioned geometrically with C—H = 0.98 and 0.97 Å, respectively, and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C). The remaining H-atoms were located in a difference Fourier map and refined isotropically. The H atom of the OH group was disordered over two orientations. During the refinement process, the disordered H2A and H2B atoms were refined with equal occupancies.

Figures

Fig. 1.

The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level.

Fig. 2.

A view of the crystal packing of the title compound. The O-H···O and C-H···O hydrogen bonds are shown as dashed lines.

Crystal data

C7H10Cl2O2	F(000) = 816
Mr = 197.05	Dx = 1.484 Mg m−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 4978 reflections
a = 21.9202 (5) Å	θ = 2.3–26.4°
b = 9.9343 (3) Å	µ = 0.68 mm−1
c = 8.1005 (2) Å	T = 294 K
V = 1763.98 (8) Å3	Block, colorless
Z = 8	0.32 × 0.20 × 0.15 mm

Data collection

Rigaku R-AXIS RAPID-S diffractometer	1801 independent reflections
Radiation source: fine-focus sealed tube	1267 reflections with I > 2σ(I)
graphite	Rint = 0.110
ω scans	θmax = 26.4°, θmin = 2.3°
Absorption correction: multi-scan (Blessing, 1995)	h = −27→27
Tmin = 0.845, Tmax = 0.900	k = −12→12
32813 measured reflections	l = −9→10

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.088	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.190	H atoms treated by a mixture of independent and constrained refinement
S = 1.18	w = 1/[σ2(Fo2) + (0.020P)2 + 5.1831P] where P = (Fo2 + 2Fc2)/3
1801 reflections	(Δ/σ)max < 0.001
115 parameters	Δρmax = 0.28 e Å−3
2 restraints	Δρmin = −0.34 e Å−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cl1	0.59049 (9)	0.41547 (16)	0.1157 (2)	0.0883 (6)
Cl2	0.62620 (9)	1.07361 (16)	0.1076 (2)	0.0841 (6)
O1	0.7389 (2)	0.8227 (5)	0.1601 (7)	0.1017 (17)
O2	0.5199 (2)	0.8930 (5)	0.0928 (7)	0.0941 (16)
H2A	0.511 (7)	0.945 (11)	0.017 (12)	0.090*	0.50
H2B	0.5050	0.8950	0.1900	0.090*	0.50
C1	0.7119 (3)	0.7145 (7)	0.0682 (10)	0.084 (2)
H1	0.7361	0.6806	−0.0247	0.101*
C2	0.6766 (2)	0.6091 (6)	0.1650 (9)	0.0732 (18)
H21	0.7003	0.5271	0.1751	0.088*
H22	0.6672	0.6421	0.2748	0.088*
C3	0.6182 (3)	0.5825 (6)	0.0692 (8)	0.0604 (15)
H3	0.628 (3)	0.578 (7)	−0.042 (9)	0.10 (2)*
C4	0.5669 (2)	0.6810 (5)	0.1042 (8)	0.0610 (14)
H41	0.5303	0.6467	0.0516	0.073*
H42	0.5595	0.6806	0.2223	0.073*
C5	0.5748 (2)	0.8269 (6)	0.0507 (8)	0.0582 (14)
H5	0.580 (2)	0.832 (5)	−0.066 (7)	0.057 (16)*
C6	0.6294 (3)	0.8926 (5)	0.1265 (7)	0.0558 (13)
H6	0.636 (2)	0.873 (5)	0.231 (7)	0.066 (18)*
C7	0.6885 (2)	0.8499 (6)	0.0502 (8)	0.0703 (17)
H7	0.6993	0.8954	−0.0531	0.084*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Cl1	0.1032 (13)	0.0592 (9)	0.1024 (14)	−0.0091 (8)	−0.0189 (11)	0.0044 (9)
Cl2	0.1150 (14)	0.0573 (9)	0.0799 (11)	−0.0025 (9)	0.0052 (10)	−0.0046 (8)
O1	0.067 (3)	0.095 (4)	0.143 (5)	−0.021 (3)	−0.030 (3)	0.028 (3)
O2	0.067 (3)	0.084 (3)	0.132 (5)	0.024 (2)	0.023 (3)	0.012 (3)
C1	0.049 (3)	0.097 (5)	0.107 (6)	0.011 (3)	0.009 (4)	0.011 (5)
C2	0.055 (3)	0.069 (4)	0.096 (5)	0.014 (3)	−0.016 (3)	0.010 (3)
C3	0.066 (4)	0.052 (3)	0.063 (4)	0.001 (3)	0.001 (3)	−0.005 (3)
C4	0.049 (3)	0.058 (3)	0.075 (4)	0.001 (2)	−0.009 (3)	−0.004 (3)
C5	0.050 (3)	0.064 (3)	0.061 (4)	0.008 (3)	−0.001 (3)	0.004 (3)
C6	0.066 (3)	0.049 (3)	0.052 (3)	0.001 (2)	−0.009 (3)	0.000 (3)
C7	0.052 (3)	0.075 (4)	0.084 (4)	−0.006 (3)	0.009 (3)	0.014 (3)

Geometric parameters (Å, °)

Cl1—C3	1.806 (6)	C3—C2	1.520 (8)
Cl2—C6	1.806 (6)	C3—C4	1.518 (7)
O1—C1	1.434 (8)	C3—H3	0.93 (7)
O1—C7	1.443 (7)	C4—C5	1.522 (8)
O2—C5	1.413 (7)	C4—H41	0.9700
O2—H2B	0.853 (5)	C4—H42	0.9700
O2—H2A	0.82 (2)	C5—H5	0.95 (5)
C1—C7	1.447 (9)	C6—C5	1.497 (8)
C1—H1	0.9800	C6—C7	1.497 (8)
C2—C1	1.521 (8)	C6—H6	0.88 (6)
C2—H21	0.9700	C7—H7	0.9800
C2—H22	0.9700
C5—O2—H2B	124.0 (5)	C3—C4—H41	107.7
C5—O2—H2A	109 (10)	C3—C4—H42	107.7
H2B—O2—H2A	125 (10)	C5—C4—H41	107.7
C1—O1—C7	60.4 (4)	C5—C4—H42	107.7
O1—C1—C2	117.3 (6)	H42—C4—H41	107.1
O1—C1—C7	60.1 (4)	O2—C5—C4	106.1 (5)
O1—C1—H1	115.7	O2—C5—C6	112.3 (5)
C2—C1—H1	115.7	O2—C5—H5	109 (3)
C7—C1—C2	120.7 (5)	C4—C5—H5	110 (3)
C7—C1—H1	115.7	C6—C5—C4	112.9 (5)
C1—C2—H21	110.4	C6—C5—H5	107 (3)
C1—C2—H22	110.4	Cl2—C6—H6	108 (4)
C3—C2—C1	106.6 (5)	C5—C6—Cl2	111.6 (4)
C3—C2—H21	110.4	C5—C6—C7	113.6 (5)
C3—C2—H22	110.4	C5—C6—H6	116 (4)
H21—C2—H22	108.6	C7—C6—Cl2	106.3 (4)
Cl1—C3—H3	104 (4)	C7—C6—H6	101 (4)
C2—C3—Cl1	109.6 (4)	O1—C7—C1	59.5 (4)
C2—C3—H3	108 (4)	O1—C7—C6	117.4 (6)
C4—C3—Cl1	107.7 (4)	O1—C7—H7	115.4
C4—C3—C2	114.6 (5)	C1—C7—C6	122.0 (5)
C4—C3—H3	113 (4)	C1—C7—H7	115.4
C3—C4—C5	118.4 (5)	C6—C7—H7	115.4
C7—O1—C1—C2	−111.5 (6)	C3—C4—C5—O2	177.8 (5)
C1—O1—C7—C6	112.7 (6)	C3—C4—C5—C6	−58.7 (7)
O1—C1—C7—C6	−105.2 (7)	Cl2—C6—C5—O2	−44.3 (6)
C2—C1—C7—O1	105.9 (8)	Cl2—C6—C5—C4	−164.2 (4)
C2—C1—C7—C6	0.7 (10)	C7—C6—C5—O2	−164.5 (5)
C3—C2—C1—O1	135.8 (5)	C7—C6—C5—C4	75.6 (7)
C3—C2—C1—C7	66.0 (8)	Cl2—C6—C7—C1	168.9 (6)
Cl1—C3—C2—C1	154.6 (5)	Cl2—C6—C7—O1	99.4 (5)
C4—C3—C2—C1	−84.1 (7)	C5—C6—C7—O1	−137.5 (5)
Cl1—C3—C4—C5	−170.8 (4)	C5—C6—C7—C1	−68.0 (8)
C2—C3—C4—C5	66.8 (7)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O2i	0.83 (11)	1.96 (11)	2.746 (7)	159 (12)
O2—H2B···O2ii	0.85	1.84	2.692 (8)	174
C2—H21···O1iii	0.97	2.43	3.398 (7)	172

Symmetry codes: (i) −x+1, −y+2, −z; (ii) −x+1, y, −z+1/2; (iii) −x+3/2, y−1/2, z.