trans-3-Acetyl-5-benzoyl-2-methyl-4-phenyl-4,5-di­hydro­furan at 150 K

In the title compound, C₂₀H₁₈O₃, the benzoyl and phenyl groups lie on opposite sides of the di­hydro­furan ring. The di­hydro­furan ring adopts a conformation intermediate between an envelope and a half-chair. The crystal packing is characterized by van der Waals forces and C—H...O interactions.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.051
• wR factor = 0.149
• Data-to-parameter ratio = 22.7

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.95

Alert level B
PLAT031_ALERT_4_B Refined Extinction Parameter within Range ......       1.32 Sigma

Alert level C
PLAT380_ALERT_4_C Incorrectly Oriented X(sp2)-Methyl Moiety ......         C6

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   2 ALERT type 4 Improvement, methodology, query or suggestion

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S1. Comment

Dihydrofurans represent an important class of heterocycles, characterized by highly pronounced insect antifeedant activities (Gebbinck et al., 1999), and they have been characterized by elemental analysis, IR, ¹H, ¹³C and two-dimensional NMR spectroscopic methods. Dihydrofurans have also been found to possess antifungal (Pour et al., 2003; Kunes et al., 2001) and anti-inflammatory (Kumar et al., 2003) properties. Since the title compound, (I), has several reactive functional groups, it can also serve as a starting material for the synthesis of novel heterocycles. A series of investigations on the synthesis, NMR and crystal structure elucidation of hydrofuran derivatives is being carried out in our laboratory.

Fig. 1 shows the atom-numbering scheme adopted for (I). The two phenyl rings are planar while the five-membered dihydrofuran ring adopts a conformation intermediate between an envelope and a half-chair; this seems to be different from the conformations observed in related structures, viz. (3S,5S,1'S)-3-benzyl-5-[1'-(tert-butoxycarbonylamino)-2'-phenylethyl]- 4,5-dihydrofuran-2(3H)-one (Sopková et al., 1996), methyl 4-hydroxy-3-[4-methoxy-2-methoxymethylenoxy)phenyl]-2-{[4-methoxy-2- (methoxymethylenoxy)phenyl]methyl}-5-oxo-2,5-dihydrofuran-2-carboxylate (Boehlow et al., 1997) and 5-hydroxy-2,2-dimethyl-5-phenyl-2,5-dihydrofuran-3-carbonitrile (Ferguson, 1990). The C—C and C—O distances (Table 1) agree well with those in similar dihydrofuran derivatives.

The carbonyl group C8═O3 is oriented away from the phenyl ring at C4 to avoid electronic repulsion. The benzoyl group at C3 and the phenyl group at C4 lie on opposite sides of the dihydrofuran ring. This is evident from the torsion angle H4—C4—C3—C8 value of 9.9 (1)°; this value, close to zero, indicates that atoms H4 and C8 are eclipsed. This configuration, to avoid steric interactions between the two phenyl rings, is probably established in the cyclization step of the formation of the compound. Fig. 2 shows the arrangement of molecules as stacked layers, viewed down the b axis. Apart from the C—H···O hydrogen-bond interactions listed in Table 2, there are no other notable intermolecular contacts.

S2. Experimental

The title dihydrofuran was obtained by the reaction of acetylacetone (100 mg, 0.001 mol) with 2,2'-sulfonylbis(1,3-diphenylprop-2-en-1-one) (478 mg, 0.001 mol) in the presence of sodium ethoxide (0.002 mol) in dimethylformamide (10 ml). Colourless single crystals of the compound were obtained as transparent plates from its saturated solution in methanol, by slow evaporation at room temperature.

S3. Refinement

The H atoms were placed in calculated positions and were allowed to ride on their respective carrier atoms. The C—H lengths are 0.98 Å for methyl H atoms, 1.00 Å for other Csp³—H and 0.95 Å for Csp²—H. For methyl H atoms, U_iso values were set equvalues were was set equal to 1.2U_eq of the carrier atom.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecular structure of (I), with the atom-numbering scheme and 50% probability displacement ellipsoids.
	Fig. 2. Packing of the molecules of (I), viewed down the b axis.

trans-3-Acetyl-5-benzoyl-2-methyl-4-phenyl-4,5-dihydrofuran

Crystal data

C20H18O3	F(000) = 648
Mr = 306.34	Dx = 1.301 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1024 reflections
a = 9.846 (2) Å	θ = 2.2–26.3°
b = 10.564 (2) Å	µ = 0.09 mm^−1
c = 16.340 (3) Å	T = 150 K
β = 113.023 (2)°	Plate, colourless
V = 1564.2 (5) Å^3	0.28 × 0.22 × 0.10 mm
Z = 4

Data collection

Bruker SMART CCD diffractometer	4750 independent reflections
Radiation source: fine-focus sealed tube	3623 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
Detector resolution: 8 pixels mm^-1	θmax = 30.5°, θmin = 2.3°
ω scans	h = −14→14
Absorption correction: multi-scan (SADABS; Bruker, 1998)	k = −15→15
Tmin = 0.95, Tmax = 0.99	l = −22→22
21162 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.051	H-atom parameters constrained
wR(F^2) = 0.149	w = 1/[σ^2(Fo^2) + (0.0745P)^2 + 0.5171P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max < 0.001
4750 reflections	Δρmax = 0.45 e Å^−3
209 parameters	Δρmin = −0.42 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0025 (19)

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
O1	0.29836 (11)	−0.02468 (10)	0.21634 (6)	0.0317 (2)
O2	0.03830 (12)	0.18776 (11)	−0.01268 (7)	0.0351 (3)
O3	0.47589 (11)	0.15842 (12)	0.31227 (7)	0.0349 (3)
C1	0.13260 (13)	0.12574 (12)	0.13887 (8)	0.0221 (2)
C2	0.23062 (14)	0.03699 (13)	0.13768 (8)	0.0257 (3)
C3	0.25767 (14)	0.03759 (13)	0.28226 (8)	0.0236 (3)
H3	0.2278	−0.0258	0.3175	0.028*
C4	0.12611 (13)	0.12888 (12)	0.23049 (8)	0.0206 (2)
H4	0.1506	0.2161	0.2557	0.025*
C5	0.04548 (14)	0.20582 (13)	0.06339 (8)	0.0250 (3)
C6	−0.03817 (17)	0.31478 (15)	0.08198 (10)	0.0330 (3)
H6A	−0.0920	0.3609	0.0267	0.049*
H6B	0.0315	0.3721	0.1254	0.049*
H6C	−0.1082	0.2819	0.1059	0.049*
C7	0.27967 (17)	−0.00506 (17)	0.06673 (10)	0.0364 (3)
H7A	0.3530	−0.0726	0.0898	0.055*
H7B	0.3237	0.0666	0.0478	0.055*
H7C	0.1946	−0.0368	0.0158	0.055*
C8	0.39049 (14)	0.11480 (13)	0.34269 (8)	0.0232 (2)
C9	0.40904 (13)	0.14052 (12)	0.43631 (8)	0.0216 (2)
C10	0.53402 (15)	0.20871 (13)	0.49053 (9)	0.0290 (3)
H10	0.6026	0.2379	0.4670	0.035*
C11	0.55789 (18)	0.23374 (15)	0.57856 (10)	0.0365 (3)
H11	0.6426	0.2803	0.6149	0.044*
C12	0.45867 (19)	0.19110 (16)	0.61367 (10)	0.0376 (4)
H12	0.4755	0.2083	0.6739	0.045*
C13	0.33505 (18)	0.12346 (16)	0.56067 (10)	0.0348 (3)
H13	0.2673	0.0941	0.5848	0.042*
C14	0.30931 (15)	0.09814 (14)	0.47198 (9)	0.0270 (3)
H14	0.2240	0.0521	0.4359	0.032*
C15	−0.02040 (14)	0.08794 (12)	0.23294 (8)	0.0214 (2)
C16	−0.07281 (15)	0.14645 (13)	0.29180 (8)	0.0258 (3)
H16	−0.0163	0.2116	0.3301	0.031*
C17	−0.20727 (16)	0.11008 (15)	0.29483 (9)	0.0299 (3)
H17	−0.2412	0.1500	0.3354	0.036*
C18	−0.29162 (15)	0.01543 (15)	0.23839 (9)	0.0302 (3)
H18	−0.3834	−0.0090	0.2400	0.036*
C19	−0.24020 (15)	−0.04308 (13)	0.17952 (9)	0.0278 (3)
H19	−0.2975	−0.1076	0.1409	0.033*
C20	−0.10536 (14)	−0.00780 (12)	0.17667 (8)	0.0240 (3)
H20	−0.0712	−0.0487	0.1365	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0330 (5)	0.0351 (5)	0.0232 (5)	0.0121 (4)	0.0068 (4)	−0.0028 (4)
O2	0.0395 (6)	0.0430 (6)	0.0216 (5)	−0.0019 (5)	0.0107 (4)	0.0022 (4)
O3	0.0260 (5)	0.0526 (7)	0.0284 (5)	−0.0046 (4)	0.0133 (4)	0.0038 (4)
C1	0.0208 (5)	0.0263 (6)	0.0188 (5)	−0.0013 (4)	0.0073 (4)	−0.0009 (4)
C2	0.0231 (6)	0.0311 (6)	0.0206 (6)	0.0006 (5)	0.0059 (4)	−0.0048 (5)
C3	0.0229 (6)	0.0266 (6)	0.0197 (5)	0.0022 (5)	0.0065 (4)	−0.0006 (4)
C4	0.0202 (5)	0.0230 (6)	0.0178 (5)	0.0007 (4)	0.0066 (4)	−0.0012 (4)
C5	0.0216 (6)	0.0287 (6)	0.0229 (6)	−0.0032 (5)	0.0068 (4)	0.0014 (5)
C6	0.0310 (7)	0.0349 (7)	0.0305 (7)	0.0084 (6)	0.0092 (5)	0.0066 (6)
C7	0.0292 (7)	0.0504 (9)	0.0292 (7)	0.0037 (6)	0.0111 (6)	−0.0138 (6)
C8	0.0194 (5)	0.0286 (6)	0.0206 (5)	0.0029 (4)	0.0067 (4)	0.0028 (4)
C9	0.0204 (5)	0.0235 (6)	0.0198 (5)	0.0036 (4)	0.0066 (4)	0.0027 (4)
C10	0.0261 (6)	0.0293 (7)	0.0283 (6)	−0.0012 (5)	0.0068 (5)	−0.0018 (5)
C11	0.0366 (8)	0.0342 (7)	0.0292 (7)	0.0037 (6)	0.0027 (6)	−0.0074 (6)
C12	0.0466 (9)	0.0397 (8)	0.0225 (6)	0.0165 (7)	0.0094 (6)	−0.0020 (6)
C13	0.0397 (8)	0.0436 (8)	0.0257 (7)	0.0126 (6)	0.0178 (6)	0.0076 (6)
C14	0.0253 (6)	0.0328 (7)	0.0241 (6)	0.0019 (5)	0.0108 (5)	0.0037 (5)
C15	0.0215 (5)	0.0233 (6)	0.0186 (5)	0.0010 (4)	0.0071 (4)	0.0005 (4)
C16	0.0264 (6)	0.0297 (6)	0.0217 (6)	0.0008 (5)	0.0098 (5)	−0.0031 (5)
C17	0.0281 (7)	0.0395 (8)	0.0254 (6)	0.0042 (5)	0.0141 (5)	0.0014 (5)
C18	0.0224 (6)	0.0392 (7)	0.0286 (6)	−0.0003 (5)	0.0097 (5)	0.0079 (5)
C19	0.0270 (6)	0.0268 (6)	0.0256 (6)	−0.0040 (5)	0.0059 (5)	0.0028 (5)
C20	0.0254 (6)	0.0244 (6)	0.0209 (5)	−0.0004 (5)	0.0077 (5)	−0.0005 (4)

Geometric parameters (Å, º)

O1—C2	1.360 (2)	C9—C10	1.4019 (18)
O1—C3	1.446 (2)	C10—C11	1.389 (2)
O2—C5	1.232 (2)	C10—H10	0.9500
O3—C8	1.222 (2)	C11—C12	1.387 (3)
C1—C2	1.351 (2)	C11—H11	0.9500
C1—C5	1.465 (2)	C12—C13	1.385 (2)
C1—C4	1.524 (2)	C12—H12	0.9500
C2—C7	1.487 (2)	C13—C14	1.3960 (19)
C3—C8	1.530 (2)	C13—H13	0.9500
C3—C4	1.571 (2)	C14—H14	0.9500
C3—H3	1.0000	C15—C16	1.4005 (17)
C4—C15	1.5214 (17)	C15—C20	1.4023 (17)
C4—H4	1.0000	C16—C17	1.3978 (19)
C5—C6	1.514 (2)	C16—H16	0.9500
C6—H6A	0.9800	C17—C18	1.393 (2)
C6—H6B	0.9800	C17—H17	0.9500
C6—H6C	0.9800	C18—C19	1.394 (2)
C7—H7A	0.9800	C18—H18	0.9500
C7—H7B	0.9800	C19—C20	1.3971 (19)
C7—H7C	0.9800	C19—H19	0.9500
C8—C9	1.4929 (17)	C20—H20	0.9500
C9—C14	1.3971 (18)
C2—O1—C3	108.0 (1)	C14—C9—C10	119.18 (12)
C2—C1—C5	125.1 (1)	C14—C9—C8	123.01 (12)
C2—C1—C4	109.5 (1)	C10—C9—C8	117.80 (12)
C5—C1—C4	125.4 (1)	C11—C10—C9	120.22 (14)
C1—C2—O1	114.1 (1)	C11—C10—H10	119.9
C1—C2—C7	132.1 (1)	C9—C10—H10	119.9
O1—C2—C7	113.9 (1)	C12—C11—C10	120.33 (14)
O1—C3—C8	107.9 (1)	C12—C11—H11	119.8
O1—C3—C4	106.8 (1)	C10—C11—H11	119.8
C8—C3—C4	109.7 (1)	C13—C12—C11	119.86 (13)
O1—C3—H3	110.8	C13—C12—H12	120.1
C8—C3—H3	110.8	C11—C12—H12	120.1
C4—C3—H3	110.8	C12—C13—C14	120.42 (14)
C15—C4—C1	115.10 (10)	C12—C13—H13	119.8
C15—C4—C3	113.7 (1)	C14—C13—H13	119.8
C1—C4—C3	99.97 (9)	C13—C14—C9	119.99 (13)
C15—C4—H4	109.2	C13—C14—H14	120.0
C1—C4—H4	109.2	C9—C14—H14	120.0
C3—C4—H4	109.2	C16—C15—C20	118.9 (1)
O2—C5—C1	122.94 (13)	C16—C15—C4	120.02 (11)
O2—C5—C6	119.95 (12)	C20—C15—C4	121.1 (1)
C1—C5—C6	117.10 (11)	C17—C16—C15	120.76 (13)
C5—C6—H6A	109.5	C17—C16—H16	119.6
C5—C6—H6B	109.5	C15—C16—H16	119.6
H6A—C6—H6B	109.5	C18—C17—C16	120.10 (13)
C5—C6—H6C	109.5	C18—C17—H17	120.0
H6A—C6—H6C	109.5	C16—C17—H17	120.0
H6B—C6—H6C	109.5	C17—C18—C19	119.44 (13)
C2—C7—H7A	109.5	C17—C18—H18	120.3
C2—C7—H7B	109.5	C19—C18—H18	120.3
H7A—C7—H7B	109.5	C18—C19—C20	120.72 (13)
C2—C7—H7C	109.5	C18—C19—H19	119.6
H7A—C7—H7C	109.5	C20—C19—H19	119.6
H7B—C7—H7C	109.5	C19—C20—C15	120.10 (12)
O3—C8—C9	121.35 (12)	C19—C20—H20	119.9
O3—C8—C3	119.27 (11)	C15—C20—H20	119.9
C9—C8—C3	119.31 (11)
C5—C1—C2—O1	179.7 (1)	O3—C8—C9—C14	176.41 (13)
C4—C1—C2—O1	−0.7 (2)	C3—C8—C9—C14	−0.60 (18)
C5—C1—C2—C7	0.5 (2)	O3—C8—C9—C10	−4.63 (19)
C4—C1—C2—C7	−179.9 (1)	C3—C8—C9—C10	178.36 (11)
C3—O1—C2—C1	−7.8 (2)	C14—C9—C10—C11	−0.1 (2)
C3—O1—C2—C7	171.6 (1)	C8—C9—C10—C11	−179.07 (12)
C2—O1—C3—C8	−105.3 (1)	C9—C10—C11—C12	0.2 (2)
C2—O1—C3—C4	12.6 (1)	C10—C11—C12—C13	−0.1 (2)
C2—C1—C4—C15	−114.3 (1)	C11—C12—C13—C14	−0.2 (2)
C5—C1—C4—C15	65.3 (2)	C12—C13—C14—C9	0.4 (2)
C2—C1—C4—C3	7.9 (1)	C10—C9—C14—C13	−0.2 (2)
C5—C1—C4—C3	−172.5 (1)	C8—C9—C14—C13	178.71 (12)
O1—C3—C4—C15	111.1 (1)	C1—C4—C15—C16	−144.77 (12)
C8—C3—C4—C15	−132.2 (1)	C3—C4—C15—C16	100.74 (14)
O1—C3—C4—C1	−12.1 (1)	C1—C4—C15—C20	34.96 (16)
C8—C3—C4—C1	104.6 (1)	C3—C4—C15—C20	−79.53 (14)
C2—C1—C5—O2	10.4 (2)	C20—C15—C16—C17	0.2 (2)
C4—C1—C5—O2	−169.2 (1)	C4—C15—C16—C17	179.92 (12)
C2—C1—C5—C6	−169.6 (1)	C15—C16—C17—C18	−0.6 (2)
C4—C1—C5—C6	10.81 (19)	C16—C17—C18—C19	0.5 (2)
O1—C3—C8—O3	30.3 (2)	C17—C18—C19—C20	0.0 (2)
C4—C3—C8—O3	−85.7 (2)	C18—C19—C20—C15	−0.4 (2)
O1—C3—C8—C9	−152.66 (11)	C16—C15—C20—C19	0.30 (19)
C4—C3—C8—C9	91.38 (13)	C4—C15—C20—C19	−179.43 (11)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C20—H20···O2^i	0.95	2.62	3.552 (2)	166
C16—H16···O2^ii	0.95	2.63	3.426 (2)	141
C12—H12···O3^ii	0.95	2.66	3.558 (2)	157

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