1-Acetyl-2a,8b-dichloro-1-meth­oxy-1,2,2a,8b-tetra­hydro-3H-cyclo­buta[c]chromen-3-one

In the title compound, C₁₄H₁₂Cl₂O₄, the cyclo­butane ring is folded. There are inter­molecular Cl...O and C—H...O inter­actions in the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.046
• wR factor = 0.140
• Data-to-parameter ratio = 15.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety         C1
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl1    ..  O4      ..       3.08 Ang.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   2 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
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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S1. Comment

We have investigated the photo-induced reaction of 3,4-dichlorocoumarin and 2,3-dimethoxy-1,3-butadiene and obtained the title compound, (I), as one of the products. As part of this study, we have undertaken the X-ray crystallographic analysis of (I) in order to elucidate the conformation and configuration of this cycloadduct product.

The bond lengths and angles in (I) are in good agreement with expected values, except for the C3—C14 [1.581 (4) Å] bond length. Owing to the presence of Cl atom and a methoxy group, this bond is longer than the mean Csp³—Csp³ distance [1.55 (2) Å] reported for cyclobutanes (Allen et al., 1987). The cyclobutane ring is folded. The dihedral angle between the C3/C5/C14 and C5/C6/C14 planes is 31.4 (4)°. The coumarin moiety is essentially planar, with C6 deviating from the mean plane by 0.405 (5) Å. The two Cl atoms lie on the same side of the coumarin plane.

In the crystal structure of (I), molecules are linked by intermolecular Cl1···O4(3/2 − x, y − 1/2, 3/2 − z) [3.080 (3) Å] interactions. Similar interactions are observed in the related compound 4a,4c,9 b,9c-tetrahydro-4 b,4c,9 b,9c-tetrachlorocyclobuta[1,2 − a:3,4 − a']diindene- 5,10-dione (Zhang et al., 2003). These short contacts, together with intermolecular C—H···O interactions (Table 2) and van der Waals forces, stabilize the crystal structure.

S2. Experimental

Compound (I) was prepared by the photo-induced reaction of a benzene solution of 3,4-dichlorocoumarin with an excess amount of 2,3-dimethoxy-1,3-butadiene, irradiated by light of wavelength longer than 300 nm for 7 h. It was isolated by column chromatography of the reaction mixture after evaporation of the solvent on silica gel. Single crystals of (I) were obtained by slow evaporation from a petroleum ether–ethyl acetate (1:3) solution (yield 23%).

S3. Refinement

The H atoms were included in the riding-model approximation, with C—H distances of 0.93, 0.96 and 0.97 Å for aromatic, methyl and methylene H atoms, respectively, and with U_iso(H) = 1.2U_eq(aromatic and methylene C) or 1.5U_eq(methyl C).

Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003).

Figures

Fig. 1. The structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme.

1-Acetyl-2a,8 b-dichloro-1-methoxy-1,2,2a,8 b-tetrahydro-3H- cyclobuta[c]chromen-3-one

Crystal data

C14H12Cl2O4	F(000) = 648
Mr = 315.14	Dx = 1.500 Mg m^−3
Monoclinic, P21/n	Melting point: 467.2 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 12.678 (3) Å	Cell parameters from 25 reflections
b = 8.7360 (17) Å	θ = 2.0–26.0°
c = 13.185 (3) Å	µ = 0.47 mm^−1
β = 107.09 (3)°	T = 293 K
V = 1395.8 (6) Å^3	Block, colorless
Z = 4	0.43 × 0.33 × 0.28 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	1870 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.051
Graphite monochromator	θmax = 26.0°, θmin = 2.0°
ω/2θ scans	h = 0→15
Absorption correction: ψ scan (XCAD4; Harms & Wocadlo, 1995)	k = 0→10
Tmin = 0.813, Tmax = 0.876	l = −15→15
2851 measured reflections	3 standard reflections every 200 reflections
2727 independent reflections	intensity decay: none

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.140	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0637P)^2 + P] where P = (Fo^2 + 2Fc^2)/3
2727 reflections	(Δ/σ)max < 0.001
181 parameters	Δρmax = 0.33 e Å^−3
0 restraints	Δρmin = −0.30 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
Cl1	0.74570 (8)	0.19543 (11)	0.72000 (7)	0.0541 (3)
Cl2	0.61485 (7)	0.08808 (10)	0.48364 (7)	0.0476 (3)
O1	0.8303 (3)	−0.0642 (3)	0.3948 (2)	0.0717 (8)
O2	0.86173 (17)	0.3151 (2)	0.43481 (17)	0.0390 (5)
O3	0.9417 (2)	0.4089 (3)	0.7044 (2)	0.0611 (7)
O4	0.80183 (17)	0.5250 (3)	0.59365 (16)	0.0388 (5)
C1	0.7267 (3)	0.1100 (5)	0.2647 (3)	0.0567 (10)
H1A	0.7192	0.0250	0.2170	0.085*
H1B	0.7640	0.1924	0.2413	0.085*
H1C	0.6550	0.1436	0.2658	0.085*
C2	0.7925 (3)	0.0617 (4)	0.3741 (3)	0.0415 (8)
C3	0.8132 (2)	0.1812 (3)	0.4620 (2)	0.0338 (7)
C4	0.9707 (3)	0.2937 (5)	0.4253 (4)	0.0628 (11)
H4A	0.9979	0.3892	0.4071	0.094*
H4B	0.9683	0.2197	0.3709	0.094*
H4C	1.0188	0.2577	0.4916	0.094*
C5	0.8686 (3)	0.1284 (4)	0.5770 (3)	0.0417 (8)
H5A	0.8542	0.0224	0.5903	0.050*
H5B	0.9467	0.1516	0.6030	0.050*
C6	0.7951 (2)	0.2427 (4)	0.6114 (2)	0.0357 (7)
C7	0.8527 (3)	0.3969 (4)	0.6395 (2)	0.0399 (7)
C8	0.7041 (2)	0.5234 (3)	0.5087 (2)	0.0310 (6)
C9	0.6598 (3)	0.6645 (4)	0.4769 (3)	0.0403 (7)
H9	0.6944	0.7523	0.5108	0.048*
C10	0.5633 (3)	0.6762 (4)	0.3939 (3)	0.0462 (8)
H10	0.5321	0.7715	0.3721	0.055*
C11	0.5140 (3)	0.5446 (4)	0.3441 (3)	0.0485 (9)
H11	0.4492	0.5516	0.2883	0.058*
C12	0.5594 (3)	0.4026 (4)	0.3760 (3)	0.0422 (8)
H12	0.5249	0.3150	0.3418	0.051*
C13	0.6570 (2)	0.3899 (3)	0.4592 (2)	0.0304 (6)
C14	0.7121 (2)	0.2407 (3)	0.4981 (2)	0.0317 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0626 (6)	0.0650 (6)	0.0392 (5)	0.0042 (5)	0.0220 (4)	0.0161 (4)
Cl2	0.0439 (5)	0.0364 (4)	0.0636 (6)	−0.0099 (4)	0.0175 (4)	−0.0009 (4)
O1	0.094 (2)	0.0428 (16)	0.0707 (19)	0.0205 (15)	0.0122 (16)	−0.0073 (13)
O2	0.0359 (11)	0.0371 (12)	0.0462 (13)	−0.0001 (9)	0.0157 (10)	0.0047 (10)
O3	0.0425 (14)	0.0682 (18)	0.0548 (15)	−0.0048 (13)	−0.0131 (12)	0.0078 (14)
O4	0.0369 (12)	0.0372 (12)	0.0356 (12)	−0.0012 (10)	0.0001 (9)	−0.0027 (9)
C1	0.064 (2)	0.063 (3)	0.0398 (19)	0.008 (2)	0.0102 (17)	−0.0085 (18)
C2	0.0451 (18)	0.0360 (18)	0.0461 (19)	0.0043 (14)	0.0176 (15)	−0.0013 (15)
C3	0.0363 (16)	0.0294 (16)	0.0365 (16)	0.0037 (13)	0.0119 (13)	0.0021 (13)
C4	0.042 (2)	0.071 (3)	0.082 (3)	−0.0002 (19)	0.029 (2)	0.009 (2)
C5	0.0394 (17)	0.0413 (19)	0.0423 (18)	0.0072 (14)	0.0087 (14)	0.0044 (15)
C6	0.0367 (16)	0.0399 (17)	0.0298 (15)	0.0014 (13)	0.0086 (13)	0.0063 (13)
C7	0.0352 (16)	0.049 (2)	0.0320 (16)	−0.0010 (15)	0.0046 (14)	0.0007 (15)
C8	0.0313 (15)	0.0322 (15)	0.0285 (14)	0.0021 (13)	0.0072 (12)	0.0000 (12)
C9	0.0480 (19)	0.0267 (16)	0.0437 (18)	−0.0011 (14)	0.0093 (15)	−0.0042 (14)
C10	0.053 (2)	0.0386 (19)	0.0426 (19)	0.0131 (16)	0.0075 (16)	0.0032 (15)
C11	0.0409 (18)	0.056 (2)	0.0395 (18)	0.0130 (16)	−0.0020 (15)	0.0013 (16)
C12	0.0375 (17)	0.0435 (19)	0.0400 (18)	−0.0003 (15)	0.0025 (14)	−0.0046 (15)
C13	0.0320 (15)	0.0300 (16)	0.0303 (15)	−0.0001 (12)	0.0111 (12)	0.0007 (12)
C14	0.0315 (15)	0.0295 (15)	0.0338 (15)	−0.0039 (12)	0.0092 (13)	−0.0004 (12)

Geometric parameters (Å, º)

Cl1—C6	1.772 (3)	C4—H4C	0.9600
Cl2—C14	1.787 (3)	C5—C6	1.524 (4)
O1—C2	1.199 (4)	C5—H5A	0.9700
O2—C3	1.416 (4)	C5—H5B	0.9700
O2—C4	1.435 (4)	C6—C7	1.525 (5)
O3—C7	1.203 (4)	C6—C14	1.553 (4)
O4—C7	1.343 (4)	C8—C9	1.369 (4)
O4—C8	1.405 (3)	C8—C13	1.383 (4)
C1—C2	1.499 (5)	C9—C10	1.385 (5)
C1—H1A	0.9600	C9—H9	0.9300
C1—H1B	0.9600	C10—C11	1.379 (5)
C1—H1C	0.9600	C10—H10	0.9300
C2—C3	1.525 (4)	C11—C12	1.380 (5)
C3—C5	1.542 (4)	C11—H11	0.9300
C3—C14	1.581 (4)	C12—C13	1.397 (4)
C4—H4A	0.9600	C12—H12	0.9300
C4—H4B	0.9600	C13—C14	1.496 (4)
C3—O2—C4	114.5 (3)	C7—C6—C14	112.6 (2)
C7—O4—C8	123.0 (2)	C5—C6—Cl1	118.7 (2)
C2—C1—H1A	109.5	C7—C6—Cl1	105.5 (2)
C2—C1—H1B	109.5	C14—C6—Cl1	118.3 (2)
H1A—C1—H1B	109.5	O3—C7—O4	118.2 (3)
C2—C1—H1C	109.5	O3—C7—C6	122.2 (3)
H1A—C1—H1C	109.5	O4—C7—C6	119.6 (2)
H1B—C1—H1C	109.5	C9—C8—C13	122.3 (3)
O1—C2—C1	123.4 (3)	C9—C8—O4	114.9 (3)
O1—C2—C3	119.1 (3)	C13—C8—O4	122.8 (3)
C1—C2—C3	117.5 (3)	C8—C9—C10	119.7 (3)
O2—C3—C2	111.3 (2)	C8—C9—H9	120.1
O2—C3—C5	113.0 (3)	C10—C9—H9	120.1
C2—C3—C5	118.0 (3)	C11—C10—C9	119.1 (3)
O2—C3—C14	104.8 (2)	C11—C10—H10	120.5
C2—C3—C14	118.7 (3)	C9—C10—H10	120.5
C5—C3—C14	88.7 (2)	C10—C11—C12	121.0 (3)
O2—C4—H4A	109.5	C10—C11—H11	119.5
O2—C4—H4B	109.5	C12—C11—H11	119.5
H4A—C4—H4B	109.5	C11—C12—C13	120.3 (3)
O2—C4—H4C	109.5	C11—C12—H12	119.8
H4A—C4—H4C	109.5	C13—C12—H12	119.8
H4B—C4—H4C	109.5	C8—C13—C12	117.6 (3)
C6—C5—C3	87.4 (2)	C8—C13—C14	118.7 (2)
C6—C5—H5A	114.1	C12—C13—C14	123.7 (3)
C3—C5—H5A	114.1	C13—C14—C6	115.8 (2)
C6—C5—H5B	114.1	C13—C14—C3	121.4 (2)
C3—C5—H5B	114.1	C6—C14—C3	85.0 (2)
H5A—C5—H5B	111.3	C13—C14—Cl2	112.0 (2)
C5—C6—C7	111.1 (3)	C6—C14—Cl2	111.3 (2)
C5—C6—C14	90.4 (2)	C3—C14—Cl2	108.5 (2)
C4—O2—C3—C2	−65.5 (3)	C9—C8—C13—C12	−1.7 (4)
C4—O2—C3—C5	70.0 (3)	O4—C8—C13—C12	179.7 (3)
C4—O2—C3—C14	164.9 (3)	C9—C8—C13—C14	179.0 (3)
O1—C2—C3—O2	124.9 (3)	O4—C8—C13—C14	0.4 (4)
C1—C2—C3—O2	−54.1 (4)	C11—C12—C13—C8	1.2 (5)
O1—C2—C3—C5	−8.2 (5)	C11—C12—C13—C14	−179.5 (3)
C1—C2—C3—C5	172.9 (3)	C8—C13—C14—C6	18.7 (4)
O1—C2—C3—C14	−113.4 (4)	C12—C13—C14—C6	−160.6 (3)
C1—C2—C3—C14	67.7 (4)	C8—C13—C14—C3	−81.8 (4)
O2—C3—C5—C6	83.8 (3)	C12—C13—C14—C3	98.9 (3)
C2—C3—C5—C6	−143.9 (3)	C8—C13—C14—Cl2	147.7 (2)
C14—C3—C5—C6	−21.8 (2)	C12—C13—C14—Cl2	−31.5 (4)
C3—C5—C6—C7	−92.4 (3)	C5—C6—C14—C13	−144.3 (3)
C3—C5—C6—C14	22.2 (2)	C7—C6—C14—C13	−31.1 (3)
C3—C5—C6—Cl1	145.1 (2)	Cl1—C6—C14—C13	92.5 (3)
C8—O4—C7—O3	172.6 (3)	C5—C6—C14—C3	−21.7 (2)
C8—O4—C7—C6	−9.6 (4)	C7—C6—C14—C3	91.5 (3)
C5—C6—C7—O3	−55.2 (4)	Cl1—C6—C14—C3	−144.9 (2)
C14—C6—C7—O3	−154.9 (3)	C5—C6—C14—Cl2	86.3 (2)
Cl1—C6—C7—O3	74.6 (4)	C7—C6—C14—Cl2	−160.6 (2)
C5—C6—C7—O4	127.1 (3)	Cl1—C6—C14—Cl2	−37.0 (3)
C14—C6—C7—O4	27.4 (4)	O2—C3—C14—C13	25.3 (3)
Cl1—C6—C7—O4	−103.1 (3)	C2—C3—C14—C13	−99.8 (3)
C7—O4—C8—C9	175.7 (3)	C5—C3—C14—C13	138.7 (3)
C7—O4—C8—C13	−5.6 (4)	O2—C3—C14—C6	−92.0 (2)
C13—C8—C9—C10	1.4 (5)	C2—C3—C14—C6	142.9 (3)
O4—C8—C9—C10	−179.8 (3)	C5—C3—C14—C6	21.4 (2)
C8—C9—C10—C11	−0.6 (5)	O2—C3—C14—Cl2	157.18 (19)
C9—C10—C11—C12	0.1 (5)	C2—C3—C14—Cl2	32.2 (3)
C10—C11—C12—C13	−0.4 (5)	C5—C3—C14—Cl2	−89.4 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4A···O3^i	0.96	2.55	3.468 (5)	159

Symmetry code: (i) −x+2, −y+1, −z+1.