2-[2'-(Phenyl­sulfonyl)­ethyl]­cyclo­pentanone

The structure of the title compound, C₁₃H₁₆O₃S, prepared by the reaction of the lithium enolate of cyclo­pentanone with phenyl­vinyl sulfoxide and subsequent oxidation with m-chloro­peroxy­benzoic acid (m-CPBA), shows the phenyl­sulfonyl­ethyl side chain to be bonded to the cyclo­pentanone ring in a pseudo-equatorial orientation.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.042
• wR factor = 0.130
• Data-to-parameter ratio = 19.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

The structure of the title compound, (I), has been determined as part of an investigation into the reaction of lithium enolates of cycloalkanones with phenyl vinyl sulfoxide. The alkylation of various enolates with vinyl sulfoxides to produce keto sulfoxides has been described (Bienayme et al., 1997; Montgomery et al., 1993; Ono et al., 1985; Brown et al., 1983; Seki et al., 1975). In addition, we reported recently the structural characterization of the 2,6-dimethyl-2-[2-(phenylvinylsulfonyl)ethyl]cyclohexanone, (II), in which the substituents were orientated such that the largest alkyl group was placed in an equatorial position (Loughlin et al., 2002). Herein we report the synthesis, isolation and structural characterization of the novel monoalkylated product, (I), arising from the reaction of the lithium enolate of cyclopentanone (obtained from lithium diisopropylamide, LDA) with phenyl vinyl sulfoxide and subsequent oxidation with m-chloroperoxybenzoic acid (m-CPBA). Compound (I) represents a simple substituted ketone with different internal steric demands to that of the highly substituted cyclohexanone (II).

Compound (I) crystallizes in space group P2₁/n with one molecule in the asymmetric unit (Fig. 1). The molecules are separated by normal van der Waal distances (Fig. 2) with the bond lengths in accord with conventional values (Allen et al., 1987). The planes of the SO₂ group and the phenyl ring lie approximately normal to the plane of the alkyl chain. The cyclopentanone ring is planar about carbonyl atom C1, with C3 located above and C4 located below the plane, giving a puckered conformational structure for the ring. The structure shows that the cyclopentanone ring is alkylated at atom C2 by phenylvinyl sulfoxide, such that the alkyl substituent is placed in a pseudo-equatorial orientation. This corresponds to the equatorial phenylsulfonylethyl side chain in the derivative obtained from oxidation, viz. compound (I), where the O1—C1—C2—C6 torsion angle is found to be −42.4 (3)°. The alkyl group is in the expected more stable pseudo-equatorial orientation as it is eclipsed by the carbonyl group, corresponding to the more stable conformation of open-chain ketones. This conformation also avoids diaxial interactions (Eliel et al., 1965).

S2. Experimental

Cyclopentanone (0.55 ml, 6.220 mmol), was reacted with lithium diisopropylamide (1.95 M, 3.2 ml, 6.220 mmol) in THF (35.5 ml), at 195 K under nitrogen for 5 min. The reaction was warmed to 243 K and phenyl vinyl sulfoxide (0.83 ml, 6.220 mmol) was added over 5 min. The reaction mixture was warmed to 273 K and stirred for 45 min. Upon workup as described elsewhere (Loughlin et al., 2002), the crude sulfoxide mixture was obtained as a yellow oil (1.365 g) and oxidized to the corresponding sulfone mixture using the crude sulfoxide mixture (1.365 g, 5.775 mmol) in chloroform (20 ml), and m-CPBA (5.775 mmol) in chloroform (30 ml). Work-up of the reaction mixture was followed by silica column chromatography (hexane–ethyl acetate, 60:40). Compound (I) was obtained in conjunction with a mixture of other minor products. An analytically pure sample of compound (I) was obtained by semi-preparative HPLC (hexane–ethyl acetate, 60:40). Colourless crystals of (I) (m.p. 348–349 K) were isolated by slow evaporation of a hexane–ethyl acetate (60:20) solution. Analysis found: C 61.98, H 6.43%; calculated for C₁₃H₁₆O₃S: C 61.87, H 6.39%. ν_max(KBr)/cm⁻¹ 1733, (CO), 1299, (SO₂), 1143, (SO₂). δ_H(400 MHz,CDCl₃, p.p.m.) 7.85–7.93 (2H, m, o-C₆H₅), 7.60–7.68 (1H, m, p-C₆H₅), 7.50–7.60 (2H, m, m-C₆H₅), 3.31 (1H, ddd, J2'2' = 7, J2'1' = 3 Hz, 2'-H), 3.16 (1H, ddd, J2'2' = 7, J2'1' = 5.5, J2'1' = 3 Hz, 2'-H), 2.00–2.15 (4H, m, 2-H, 3-H, 2 × 5-H), 1.93–2.00 (2H, m, 4-H, 1'-H), 1.67–1.83 (2H, m, 4-H, 1'-H), 1.42–1.52 (1H, m, 3-H). δ_C (50 MHz, CDCl₃) 219.7 (C-1), 139.3 (i-C₆H₅), 133.7 (p-C₆H₅), 129.7 (m-C₆H₅), 128.3 (o-C₆H₅), 54.0 (C-2'), 47.5 (C-2), 37.4 (C-5), 29.3 (C-3), 22.8 (C-1'), 20.5 (C-4'). ESMS+ 259 (MLi⁺ 94%), 275 (MNa⁺, 100%). HRMS found 253.08884, C₁₃H₁₇SO₃ requires 253.0898.

S3. Refinement

H atoms were constrained as riding atoms, fixed to their parent C atoms at a C–H distance of 0.95 Å. U_iso(H) values were set to 1.2U_eq for the parent atom.

Computing details

Data collection: MSC/AFC7 Diffractometer Control Software (Molecular Structure Corporation, 1999); cell refinement: MSC/AFC7 Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1997-2001); program(s) used to solve structure: TEXSAN for Windows; program(s) used to refine structure: TEXSAN for Windows and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1980-2001) and ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: TEXSAN for Windows and PLATON.

Figures

	Fig. 1. ORTEP-3 (Farrugia, 1997) plot showing the atomic numbering scheme for the molecule in the asymmetric unit of (I). Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.
	Fig. 2. Unit-cell diagram of (I), projected down the a axis. The b axis is horizonal and the c axis is vertical.

2-[2-(Phenylsulfonyl)ethyl]cyclopentanone

Crystal data

C13H16O3S	F(000) = 536
Mr = 252.33	Dx = 1.306 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 11.986 (2) Å	θ = 12.8–17.3°
b = 12.387 (6) Å	µ = 0.25 mm^−1
c = 9.2183 (13) Å	T = 295 K
β = 110.293 (14)°	Prismatic, colorless
V = 1283.7 (7) Å^3	0.40 × 0.30 × 0.30 mm
Z = 4

Data collection

Rigaku AFC-7R diffractometer	Rint = 0.041
Radiation source: Rigaku rotating anode	θmax = 27.5°, θmin = 2.9°
Graphite monochromator	h = −5→15
ω–2θ scans	k = 0→16
3202 measured reflections	l = −11→11
2943 independent reflections	3 standard reflections every 150 reflections
2167 reflections with I > 2σ(I)	intensity decay: 0.2%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.130	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0693P)^2 + 0.2568P] where P = (Fo^2 + 2Fc^2)/3
2943 reflections	(Δ/σ)max = 0.001
154 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.35 e Å^−3

Special details

Experimental. The scan width was (1.68 + 0.30tanθ)° with an ω scan speed of 16° per minute (up to 4 scans to achieve I/σ(I) > 10). Stationary background counts were recorded at each end of the scan, and the scan time:background time ratio was 2:1.

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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 > σ(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
S1	0.34894 (4)	0.23632 (4)	0.10172 (5)	0.0460 (2)
O1	0.75325 (13)	0.05501 (15)	0.0942 (2)	0.0677 (6)
O2	0.40863 (13)	0.33382 (13)	0.1696 (2)	0.0653 (5)
O3	0.32374 (13)	0.21924 (14)	−0.06110 (17)	0.0635 (5)
C1	0.74218 (16)	0.02313 (16)	0.2124 (2)	0.0500 (6)
C2	0.62512 (15)	0.02267 (16)	0.2425 (2)	0.0452 (5)
C3	0.66010 (19)	−0.00477 (18)	0.4133 (2)	0.0568 (7)
C4	0.7733 (2)	−0.0715 (2)	0.4487 (3)	0.0766 (9)
C5	0.83819 (19)	−0.0219 (2)	0.3506 (3)	0.0694 (8)
C6	0.55606 (16)	0.12592 (17)	0.1869 (2)	0.0491 (6)
C7	0.43352 (16)	0.12544 (17)	0.2023 (2)	0.0484 (6)
C8	0.21454 (15)	0.22846 (15)	0.1393 (2)	0.0423 (5)
C9	0.12684 (18)	0.15770 (19)	0.0554 (3)	0.0579 (7)
C10	0.02135 (18)	0.1530 (2)	0.0870 (3)	0.0669 (8)
C11	0.00593 (19)	0.2175 (2)	0.1988 (3)	0.0629 (8)
C12	0.0926 (2)	0.2870 (2)	0.2798 (3)	0.0637 (8)
C13	0.19903 (18)	0.29387 (17)	0.2522 (2)	0.0526 (6)
H2	0.57850	−0.03540	0.18530	0.0540*
H3A	0.67500	0.05900	0.47420	0.0680*
H3B	0.59930	−0.04550	0.43210	0.0680*
H4A	0.82020	−0.06700	0.55540	0.0920*
H4B	0.75460	−0.14500	0.42120	0.0920*
H5A	0.88270	−0.07520	0.32010	0.0830*
H5B	0.89010	0.03380	0.40580	0.0830*
H6A	0.60050	0.18430	0.24600	0.0590*
H6B	0.54630	0.13600	0.08100	0.0590*
H7A	0.44220	0.13020	0.30850	0.0580*
H7B	0.39360	0.06030	0.16020	0.0580*
H9	0.13820	0.11320	−0.02230	0.0690*
H10	−0.04010	0.10480	0.03060	0.0800*
H11	−0.06610	0.21370	0.22000	0.0750*
H12	0.08020	0.33170	0.35660	0.0770*
H13	0.25980	0.34240	0.30950	0.0630*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0370 (2)	0.0540 (3)	0.0505 (3)	0.0040 (2)	0.0197 (2)	0.0099 (2)
O1	0.0534 (8)	0.0876 (12)	0.0724 (10)	0.0061 (8)	0.0347 (8)	0.0056 (9)
O2	0.0488 (8)	0.0576 (9)	0.0898 (11)	−0.0062 (7)	0.0245 (8)	0.0049 (8)
O3	0.0561 (8)	0.0923 (12)	0.0495 (8)	0.0138 (8)	0.0276 (7)	0.0145 (8)
C1	0.0374 (9)	0.0527 (11)	0.0588 (12)	0.0042 (8)	0.0151 (8)	−0.0081 (9)
C2	0.0374 (8)	0.0504 (10)	0.0473 (10)	−0.0006 (7)	0.0139 (7)	0.0000 (8)
C3	0.0610 (12)	0.0594 (12)	0.0482 (11)	0.0001 (10)	0.0165 (9)	0.0054 (9)
C4	0.0770 (16)	0.0677 (15)	0.0662 (15)	0.0154 (13)	0.0010 (12)	0.0123 (12)
C5	0.0467 (11)	0.0775 (15)	0.0716 (15)	0.0193 (11)	0.0049 (10)	−0.0077 (12)
C6	0.0381 (9)	0.0599 (12)	0.0536 (11)	0.0058 (8)	0.0214 (8)	0.0113 (9)
C7	0.0388 (9)	0.0571 (11)	0.0535 (10)	0.0062 (8)	0.0214 (8)	0.0124 (9)
C8	0.0354 (8)	0.0495 (10)	0.0440 (9)	0.0064 (7)	0.0163 (7)	0.0042 (8)
C9	0.0456 (10)	0.0693 (13)	0.0623 (12)	−0.0027 (9)	0.0232 (9)	−0.0146 (10)
C10	0.0388 (10)	0.0833 (16)	0.0789 (15)	−0.0056 (10)	0.0209 (10)	−0.0046 (13)
C11	0.0479 (11)	0.0768 (15)	0.0744 (14)	0.0174 (10)	0.0344 (11)	0.0175 (12)
C12	0.0685 (14)	0.0703 (14)	0.0654 (14)	0.0206 (11)	0.0397 (12)	0.0016 (11)
C13	0.0556 (11)	0.0545 (11)	0.0499 (11)	0.0049 (9)	0.0210 (9)	−0.0021 (9)

Geometric parameters (Å, º)

S1—O2	1.4323 (18)	C12—C13	1.387 (3)
S1—O3	1.4402 (17)	C2—H2	0.9504
S1—C7	1.767 (2)	C3—H3A	0.9495
S1—C8	1.764 (2)	C3—H3B	0.9504
O1—C1	1.209 (3)	C4—H4A	0.9503
C1—C2	1.522 (3)	C4—H4B	0.9508
C1—C5	1.497 (3)	C5—H5A	0.9506
C2—C3	1.521 (3)	C5—H5B	0.9500
C2—C6	1.513 (3)	C6—H6A	0.9498
C3—C4	1.524 (4)	C6—H6B	0.9503
C4—C5	1.513 (4)	C7—H7A	0.9498
C6—C7	1.524 (3)	C7—H7B	0.9496
C8—C9	1.381 (3)	C9—H9	0.9503
C8—C13	1.381 (3)	C10—H10	0.9506
C9—C10	1.394 (3)	C11—H11	0.9502
C10—C11	1.366 (4)	C12—H12	0.9502
C11—C12	1.356 (4)	C13—H13	0.9508
O3···C1^i	3.289 (3)	H3A···H6A	2.5157
O1···H6B	2.6391	H3A···C8^viii	2.9953
O1···H10^ii	2.8047	H3A···C13^viii	3.0757
O1···H7B^i	2.7883	H5A···O2^ix	2.7148
O1···H9^i	2.6593	H5B···O2^viii	2.8770
O1···H11^ii	2.8558	H6A···O2	2.8446
O1···H12^iii	2.8138	H6A···H3A	2.5157
O2···H13	2.5402	H6A···O3^viii	2.9067
O2···H5A^iv	2.7148	H6B···O1	2.6391
O2···H6A	2.8446	H6B···O3	2.7334
O2···H5B^v	2.8770	H6B···H12^iii	2.2776
O3···H6B	2.7334	H7A···C3	2.9664
O3···H9	2.7112	H7B···H2	2.4525
O3···H6A^v	2.9067	H7B···O1^i	2.7883
O3···H11^iii	2.8902	H9···O3	2.7112
C1···O3^i	3.289 (3)	H9···O1^i	2.6593
C3···H7A	2.9664	H10···O1^x	2.8047
C8···H3A^v	2.9953	H11···O1^x	2.8558
C12···H2^vi	3.0995	H11···O3^xi	2.8902
C13···H3A^v	3.0757	H12···H2^vi	2.4429
H2···H7B	2.4525	H12···O1^xi	2.8138
H2···C12^vii	3.0995	H12···H6B^xi	2.2776
H2···H12^vii	2.4429	H13···O2	2.5402
O2—S1—O3	118.14 (10)	H3A—C3—H3B	109.43
O2—S1—C7	108.51 (10)	C3—C4—H4A	110.66
O2—S1—C8	108.21 (10)	C3—C4—H4B	110.62
O3—S1—C7	107.91 (10)	C5—C4—H4A	110.65
O3—S1—C8	108.71 (9)	C5—C4—H4B	110.61
C7—S1—C8	104.53 (9)	H4A—C4—H4B	109.41
O1—C1—C2	124.19 (18)	C1—C5—H5A	110.59
O1—C1—C5	126.6 (2)	C1—C5—H5B	110.64
C2—C1—C5	109.19 (16)	C4—C5—H5A	110.63
C1—C2—C3	104.42 (16)	C4—C5—H5B	110.60
C1—C2—C6	111.45 (16)	H5A—C5—H5B	109.41
C3—C2—C6	117.49 (16)	C2—C6—H6A	108.49
C2—C3—C4	104.37 (18)	C2—C6—H6B	108.48
C3—C4—C5	104.8 (2)	C7—C6—H6A	108.45
C1—C5—C4	104.90 (19)	C7—C6—H6B	108.48
C2—C6—C7	113.38 (17)	H6A—C6—H6B	109.51
S1—C7—C6	110.13 (14)	S1—C7—H7A	109.30
S1—C8—C9	119.64 (15)	S1—C7—H7B	109.27
S1—C8—C13	119.09 (15)	C6—C7—H7A	109.34
C9—C8—C13	121.26 (19)	C6—C7—H7B	109.30
C8—C9—C10	118.6 (2)	H7A—C7—H7B	109.48
C9—C10—C11	120.2 (2)	C8—C9—H9	120.67
C10—C11—C12	120.5 (2)	C10—C9—H9	120.72
C11—C12—C13	121.0 (2)	C9—C10—H10	119.93
C8—C13—C12	118.3 (2)	C11—C10—H10	119.87
C1—C2—H2	107.67	C10—C11—H11	119.76
C3—C2—H2	107.65	C12—C11—H11	119.69
C6—C2—H2	107.73	C11—C12—H12	119.48
C2—C3—H3A	110.73	C13—C12—H12	119.49
C2—C3—H3B	110.73	C8—C13—H13	120.80
C4—C3—H3A	110.71	C12—C13—H13	120.86
C4—C3—H3B	110.79
O2—S1—C7—C6	−61.60 (15)	C6—C2—C3—C4	−151.91 (18)
O3—S1—C7—C6	67.51 (15)	C1—C2—C6—C7	175.20 (15)
C8—S1—C7—C6	−176.90 (13)	C1—C2—C3—C4	−27.9 (2)
O2—S1—C8—C9	163.86 (17)	C3—C2—C6—C7	−64.4 (2)
O2—S1—C8—C13	−15.89 (18)	C2—C3—C4—C5	35.9 (2)
O3—S1—C8—C9	34.4 (2)	C3—C4—C5—C1	−29.3 (2)
O3—S1—C8—C13	−145.36 (16)	C2—C6—C7—S1	−168.72 (13)
C7—S1—C8—C9	−80.64 (18)	S1—C8—C9—C10	−179.92 (19)
C7—S1—C8—C13	99.61 (16)	C9—C8—C13—C12	0.0 (3)
C2—C1—C5—C4	12.0 (2)	C13—C8—C9—C10	−0.2 (3)
O1—C1—C2—C3	−170.2 (2)	S1—C8—C13—C12	179.72 (16)
O1—C1—C2—C6	−42.4 (3)	C8—C9—C10—C11	0.1 (4)
C5—C1—C2—C3	10.0 (2)	C9—C10—C11—C12	0.3 (4)
C5—C1—C2—C6	137.85 (17)	C10—C11—C12—C13	−0.5 (4)
O1—C1—C5—C4	−167.8 (2)	C11—C12—C13—C8	0.3 (3)

Symmetry codes: (i) −x+1, −y, −z; (ii) x+1, y, z; (iii) x+1/2, −y+1/2, z−1/2; (iv) −x+3/2, y+1/2, −z+1/2; (v) x−1/2, −y+1/2, z−1/2; (vi) −x+1/2, y+1/2, −z+1/2; (vii) −x+1/2, y−1/2, −z+1/2; (viii) x+1/2, −y+1/2, z+1/2; (ix) −x+3/2, y−1/2, −z+1/2; (x) x−1, y, z; (xi) x−1/2, −y+1/2, z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C13—H13···O2	0.95	2.54	2.909 (3)	103