(4aSR,7SR,9aSR)-7-tert-Butyl-5,5-dioxo-1,2,4a,9a-tetra­hydro-8-oxa-5λ⁶-thia­benzocyclo­heptan-9-one

The six-membered cyclo­hexene ring of the title compound, C₁₃H₂₀O₄S, exhibits a sofa conformation, and the seven-membered ring displays an irregular chair-like conformation. Only weak inter­molecular C—H...O inter­actions are observed.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.038
• wR factor = 0.102
• Data-to-parameter ratio = 20.3

checkCIF/PLATON results

No syntax errors found



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   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
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   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
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S1. Comment

The background to this study is described in the first paper of this series (Zeller et al., 2006a).

The title compound, (I), crystallizes in the monoclinic space group P2₁/n with Z = 4 and thus as a racemic mixture of both enantiomers. In line with the six other cycloadducts described previously (Zeller et al., 2004a,b,c,d; Zeller et al., 2006a,b) the six-membered ring of (I) exhibits a sofa conformation expected for cyclohexenes. In the present case, only atom C1 is non-coplanar with the other atoms of the ring. The r.m.s. fit for the plane defined by atoms C2, C3, C4 and C4a is 0.0488 Å, and the deviation for C1 from the least-squares plane is 0.646 (2) Å. For the atoms defining the plane, the largest deviation is 0.0585 (9) Å for C4A. The angles at the unsaturated C atoms are 124.15 (13)° for C4—C3—C2 and 123.39 (13)° for C3—C4—C4A (Fig. 1). The seven-membered ring displays an irregular chair-like conformation. The sterically demanding tert-butyl group at C7 is located in a pseudo-equatorial position.

All intermolecular contacts in (I) are weak, the most pronounced being two C—H···O contacts: C6···O2ⁱ with a C···O distance of 3.400 (2) Å and a C—H···O angle of 165.4°, and C9···O3ⁱⁱ with a slightly shorter C···O distance of 3.304 (1) Å but with a C—H···O angle unfavorably small for a strong interaction (96.11°) [symmetry codes: (i) −x, 1 − y, −z; (ii) 1/2 − x, −1/2 + y, 1/2 − z].

S2. Experimental

The title compound was synthesized following an analogous procedure to that described by Chumachenko et al. (2005) for related compounds. 1-[(E)-Butadienesulfonyl]-3,3-dimethyl-2-butyl acrylate (1.36 g, 5.00 mmol) was heated in toluene (450 ml, 0.011 M) at 400 K for 40 h. Crystallization of the crude reaction mixture from a minimum amount of ethyl acetate gave the title compound as a white crystalline solid (0.83 g, 3.05 mmol, 61%; m.p. 462 K). Column chromatography (dichloromethane) of the mother liquor gave, as the first fraction, an additional 0.13 g (0.48 mmol, 10%) of (I) resulting in a combined yield for (I) of 0.96 g (3.53 mmol, 71%). A small second chromatograpic fraction contained the minor endo-product (II) in about 2% yield, contaminated with traces of (I).

S3. Refinement

All H atoms were positioned geometrically (C—H = 0.95–1.00 Å). They were refined with isotropic displacement parameters of 1.5 (methyl) or 1.2 (all others) times that of the equivalent isotropic displacement parameter of the adjacent C atom. Methyl H atoms were allowed to rotate to best fit the experimental data. The s.u. values of the cell parameters are taken from the software, recognizing that the values are unreasonably small (Herbstein, 2000).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 2000); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids.

(4aSR,7SR,9aSR)-7-tert-Butyl-5,5-dioxo-1,2,4a,9a-tetrahydro-8-oxa- 5λ⁶-thiabenzocycloheptan-9-one

Crystal data

C13H20O4S	F(000) = 584
Mr = 272.35	Dx = 1.333 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 11.8554 (8) Å	Cell parameters from 6071 reflections
b = 5.6653 (4) Å	θ = 3.0–30.5°
c = 20.2326 (14) Å	µ = 0.24 mm^−1
β = 92.681 (1)°	T = 100 K
V = 1357.42 (16) Å^3	Block, colourless
Z = 4	0.45 × 0.38 × 0.36 mm

Data collection

Bruker SMART APEX CCD diffractometer	3368 independent reflections
Radiation source: fine-focus sealed tube	3308 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ω scans	θmax = 28.3°, θmin = 2.0°
Absorption correction: multi-scan (SADABS in SAINT-Plus; Bruker, 2003)	h = −15→15
Tmin = 0.850, Tmax = 0.916	k = −7→7
13221 measured reflections	l = −26→26

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.102	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0494P)^2 + 0.6798P] where P = (Fo^2 + 2Fc^2)/3
3368 reflections	(Δ/σ)max < 0.001
166 parameters	Δρmax = 0.52 e Å^−3
0 restraints	Δρmin = −0.25 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > 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
C1	0.01198 (11)	0.5087 (3)	0.26033 (7)	0.0229 (3)
H1A	−0.0263	0.6170	0.2281	0.027*
H1B	0.0637	0.6034	0.2896	0.027*
O1	−0.11615 (8)	0.1872 (2)	0.06305 (5)	0.0248 (2)
C2	−0.07571 (12)	0.3881 (3)	0.30145 (7)	0.0279 (3)
H2A	−0.0374	0.3104	0.3402	0.034*
H2B	−0.1281	0.5081	0.3180	0.034*
O2	−0.01989 (8)	0.55452 (17)	0.10105 (4)	0.0198 (2)
C3	−0.14147 (12)	0.2078 (3)	0.26138 (8)	0.0265 (3)
H3	−0.2114	0.1558	0.2772	0.032*
O3	0.20304 (8)	0.6403 (2)	0.19016 (5)	0.0250 (2)
C4	−0.10813 (11)	0.1162 (3)	0.20519 (7)	0.0234 (3)
H4	−0.1577	0.0111	0.1816	0.028*
C4A	0.00434 (10)	0.1704 (2)	0.17689 (6)	0.0169 (2)
H4A	0.0445	0.0170	0.1713	0.020*
S5	−0.01895 (2)	0.29984 (6)	0.094887 (15)	0.01582 (10)
C6	0.10047 (10)	0.2180 (2)	0.04937 (6)	0.0170 (2)
H6A	0.1097	0.0445	0.0514	0.020*
H6B	0.0861	0.2622	0.0024	0.020*
C7	0.20965 (10)	0.3344 (2)	0.07516 (6)	0.0142 (2)
H7	0.2029	0.5094	0.0699	0.017*
O8	0.22015 (7)	0.27662 (17)	0.14540 (4)	0.0165 (2)
C9	0.17296 (10)	0.4388 (2)	0.18640 (6)	0.0180 (3)
C9A	0.07954 (10)	0.3259 (2)	0.22368 (6)	0.0181 (3)
H9A	0.1161	0.2192	0.2577	0.022*
C10	0.31605 (10)	0.2488 (2)	0.04198 (6)	0.0148 (2)
C11	0.33213 (11)	−0.0176 (2)	0.05052 (7)	0.0194 (3)
H11A	0.3288	−0.0586	0.0974	0.029*
H11B	0.4057	−0.0636	0.0345	0.029*
H11C	0.2721	−0.1011	0.0251	0.029*
C12	0.30485 (11)	0.3102 (2)	−0.03199 (6)	0.0203 (3)
H12A	0.3750	0.2693	−0.0530	0.031*
H12B	0.2903	0.4796	−0.0372	0.031*
H12C	0.2421	0.2208	−0.0529	0.031*
C13	0.41877 (10)	0.3765 (2)	0.07401 (6)	0.0183 (3)
H13A	0.4244	0.3410	0.1215	0.027*
H13B	0.4101	0.5471	0.0676	0.027*
H13C	0.4875	0.3228	0.0534	0.027*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0210 (6)	0.0308 (7)	0.0170 (6)	−0.0009 (5)	0.0022 (5)	−0.0053 (5)
O1	0.0147 (4)	0.0328 (6)	0.0264 (5)	−0.0004 (4)	−0.0037 (4)	−0.0105 (4)
C2	0.0208 (6)	0.0442 (9)	0.0192 (6)	0.0029 (6)	0.0050 (5)	−0.0001 (6)
O2	0.0221 (5)	0.0185 (5)	0.0186 (4)	0.0040 (3)	−0.0008 (4)	0.0006 (3)
C3	0.0177 (6)	0.0320 (8)	0.0305 (7)	0.0015 (5)	0.0070 (5)	0.0068 (6)
O3	0.0231 (5)	0.0286 (5)	0.0233 (5)	−0.0082 (4)	0.0013 (4)	−0.0084 (4)
C4	0.0164 (6)	0.0226 (7)	0.0315 (7)	−0.0023 (5)	0.0043 (5)	0.0039 (6)
C4A	0.0144 (5)	0.0171 (6)	0.0192 (6)	0.0006 (4)	0.0020 (4)	0.0034 (5)
S5	0.01296 (16)	0.01840 (18)	0.01586 (16)	0.00110 (10)	−0.00185 (11)	−0.00239 (11)
C6	0.0146 (6)	0.0209 (6)	0.0156 (6)	0.0006 (4)	0.0004 (4)	−0.0030 (5)
C7	0.0155 (5)	0.0138 (5)	0.0134 (5)	0.0003 (4)	0.0004 (4)	0.0008 (4)
O8	0.0154 (4)	0.0216 (5)	0.0125 (4)	0.0009 (3)	0.0004 (3)	0.0016 (3)
C9	0.0145 (5)	0.0262 (7)	0.0130 (5)	−0.0006 (5)	−0.0021 (4)	−0.0019 (5)
C9A	0.0146 (5)	0.0249 (6)	0.0147 (6)	0.0008 (5)	−0.0001 (4)	0.0028 (5)
C10	0.0153 (5)	0.0128 (5)	0.0164 (5)	0.0001 (4)	0.0023 (4)	0.0004 (4)
C11	0.0182 (6)	0.0137 (6)	0.0264 (6)	0.0010 (5)	0.0028 (5)	−0.0005 (5)
C12	0.0206 (6)	0.0240 (7)	0.0168 (6)	0.0008 (5)	0.0038 (5)	0.0004 (5)
C13	0.0168 (6)	0.0171 (6)	0.0210 (6)	−0.0019 (5)	0.0015 (5)	0.0015 (5)

Geometric parameters (Å, º)

C1—C9A	1.5230 (19)	C6—H6B	0.9900
C1—C2	1.524 (2)	C7—O8	1.4580 (14)
C1—H1A	0.9900	C7—C10	1.5349 (17)
C1—H1B	0.9900	C7—H7	1.0000
O1—S5	1.4424 (10)	O8—C9	1.3743 (16)
C2—C3	1.500 (2)	C9—C9A	1.5108 (18)
C2—H2A	0.9900	C9A—H9A	1.0000
C2—H2B	0.9900	C10—C11	1.5297 (17)
O2—S5	1.4483 (10)	C10—C13	1.5336 (17)
C3—C4	1.326 (2)	C10—C12	1.5362 (17)
C3—H3	0.9500	C11—H11A	0.9800
O3—C9	1.1970 (18)	C11—H11B	0.9800
C4—C4A	1.5071 (18)	C11—H11C	0.9800
C4—H4	0.9500	C12—H12A	0.9800
C4A—C9A	1.5454 (18)	C12—H12B	0.9800
C4A—S5	1.8232 (13)	C12—H12C	0.9800
C4A—H4A	1.0000	C13—H13A	0.9800
S5—C6	1.7860 (13)	C13—H13B	0.9800
C6—C7	1.5227 (17)	C13—H13C	0.9800
C6—H6A	0.9900
C9A—C1—C2	110.40 (13)	C6—C7—C10	114.59 (10)
C9A—C1—H1A	109.6	O8—C7—H7	109.2
C2—C1—H1A	109.6	C6—C7—H7	109.2
C9A—C1—H1B	109.6	C10—C7—H7	109.2
C2—C1—H1B	109.6	C9—O8—C7	114.81 (10)
H1A—C1—H1B	108.1	O3—C9—O8	123.19 (12)
C3—C2—C1	111.16 (12)	O3—C9—C9A	126.50 (12)
C3—C2—H2A	109.4	O8—C9—C9A	110.30 (11)
C1—C2—H2A	109.4	C9—C9A—C1	111.70 (12)
C3—C2—H2B	109.4	C9—C9A—C4A	110.54 (10)
C1—C2—H2B	109.4	C1—C9A—C4A	112.61 (10)
H2A—C2—H2B	108.0	C9—C9A—H9A	107.2
C4—C3—C2	124.15 (13)	C1—C9A—H9A	107.2
C4—C3—H3	117.9	C4A—C9A—H9A	107.2
C2—C3—H3	117.9	C11—C10—C13	108.98 (10)
C3—C4—C4A	123.39 (13)	C11—C10—C7	111.26 (10)
C3—C4—H4	118.3	C13—C10—C7	108.60 (10)
C4A—C4—H4	118.3	C11—C10—C12	109.75 (11)
C4—C4A—C9A	112.26 (11)	C13—C10—C12	109.61 (10)
C4—C4A—S5	109.19 (9)	C7—C10—C12	108.62 (10)
C9A—C4A—S5	112.75 (9)	C10—C11—H11A	109.5
C4—C4A—H4A	107.5	C10—C11—H11B	109.5
C9A—C4A—H4A	107.5	H11A—C11—H11B	109.5
S5—C4A—H4A	107.5	C10—C11—H11C	109.5
O1—S5—O2	118.03 (6)	H11A—C11—H11C	109.5
O1—S5—C6	106.92 (6)	H11B—C11—H11C	109.5
O2—S5—C6	108.20 (6)	C10—C12—H12A	109.5
O1—S5—C4A	108.21 (6)	C10—C12—H12B	109.5
O2—S5—C4A	108.89 (6)	H12A—C12—H12B	109.5
C6—S5—C4A	105.96 (6)	C10—C12—H12C	109.5
C7—C6—S5	113.12 (9)	H12A—C12—H12C	109.5
C7—C6—H6A	109.0	H12B—C12—H12C	109.5
S5—C6—H6A	109.0	C10—C13—H13A	109.5
C7—C6—H6B	109.0	C10—C13—H13B	109.5
S5—C6—H6B	109.0	H13A—C13—H13B	109.5
H6A—C6—H6B	107.8	C10—C13—H13C	109.5
O8—C7—C6	105.63 (9)	H13A—C13—H13C	109.5
O8—C7—C10	108.72 (9)	H13B—C13—H13C	109.5
C9A—C1—C2—C3	−48.40 (16)	C7—O8—C9—O3	−60.85 (16)
C1—C2—C3—C4	18.1 (2)	C7—O8—C9—C9A	118.40 (11)
C2—C3—C4—C4A	4.3 (2)	O3—C9—C9A—C1	9.12 (18)
C3—C4—C4A—C9A	5.03 (19)	O8—C9—C9A—C1	−170.10 (10)
C3—C4—C4A—S5	−120.76 (14)	O3—C9—C9A—C4A	135.34 (14)
C4—C4A—S5—O1	−36.02 (11)	O8—C9—C9A—C4A	−43.88 (14)
C9A—C4A—S5—O1	−161.53 (9)	C2—C1—C9A—C9	−175.80 (11)
C4—C4A—S5—O2	93.42 (10)	C2—C1—C9A—C4A	59.12 (14)
C9A—C4A—S5—O2	−32.08 (10)	C4—C4A—C9A—C9	−162.21 (11)
C4—C4A—S5—C6	−150.39 (9)	S5—C4A—C9A—C9	−38.39 (13)
C9A—C4A—S5—C6	84.10 (10)	C4—C4A—C9A—C1	−36.50 (15)
O1—S5—C6—C7	177.08 (9)	S5—C4A—C9A—C1	87.33 (12)
O2—S5—C6—C7	48.98 (10)	O8—C7—C10—C11	59.17 (13)
C4A—S5—C6—C7	−67.67 (10)	C6—C7—C10—C11	−58.74 (14)
S5—C6—C7—O8	54.32 (12)	O8—C7—C10—C13	−60.77 (12)
S5—C6—C7—C10	173.96 (8)	C6—C7—C10—C13	−178.68 (10)
C6—C7—O8—C9	−91.29 (12)	O8—C7—C10—C12	−179.91 (10)
C10—C7—O8—C9	145.27 (10)	C6—C7—C10—C12	62.18 (13)