The title compound, C
11H
16O
3, adopts a conformation in which the
-valerolactone and cyclohexane rings are almost coplanar with one another. The
-methoxy substituent occupies an axial position with respect to the cyclohexane ring. The
-valerolactone moiety adopts a half-chair arrangement, while the cyclohexane ring exists in a chair conformation.
Supporting information
CCDC reference: 275517
The synthesis of enantiomerically pure α-methylene-δ-valerolactone, (II) (I)? was based on a highly stereoselective Michael reaction of a chiral imine derived from (R)-1-phenylethylamine and 2-methoxycyclohexanone with dicyclohexylammonium 2-(diethoxyphosphoryl)acrylate. Subsequent reduction of the carbonyl group in the adduct with KBH4 was followed by lactonization of the resulting 2-(diethoxyphosphoryl)-5-hydroxyalkanoic acid. The final step in the synthesis pathway was the Horner–Wadsworth–Emmons olefination of the resulting α-phosphono-δ-valerolactone with formaldehyde. The enantiomeric purity of (I) as higher than 0.99 was confirmed by gas-chromatographic analysis on a chiral column. Details of the procedure have been described elsewhere (Krawczyk & Śliwiński, 2003; Krawczyk, Śliwiński, Wolf & Bodalski, 2004). Colourless crystals of (I) (m.p. 397 K) were grown in 4 d by slow evaporation from a 1:1 mixture of methanol and ethyl acetate.
Methyl H atoms were placed in calculated positions [C—H = 0.96 (2) Å] and refined? All other H atoms were located in a difference Fourier map calculated after three cycles of anisotropic refinement, and their positional and isotropic displacement parameters were allowed to refine freely [C—H = 0.94 (2)–1.04 (2) Å]. The refinement of the Flack (1983) parameter is in agreement with the assigned absolute configuration. An attempt to refine the inverted structure led to a Flack parameter of 1.0 (2). Atomic charges derived from electrostatic potentials were calculated using GAUSSIAN03 (Frisch et al., 2003) at the MP2/6–311++G(d,p) level for the X-ray determined coordinates. Grid points were selected according to the CHELPG procedure of Breneman & Wiberg (1990).
Data collection: SMART (Bruker, 2003); cell refinement: SMART; data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SHELXTL (Bruker, 2003); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
(4aR,8aR)-4a-Methoxy-3-methyleneperhydrochromen-2-one
top
Crystal data top
C11H16O3 | Dx = 1.284 Mg m−3 |
Mr = 196.24 | Melting point: 397 K |
Orthorhombic, P212121 | Cu Kα radiation, λ = 1.54178 Å |
a = 6.1555 (2) Å | Cell parameters from 4441 reflections |
b = 12.3990 (2) Å | θ = 3.3–70.6° |
c = 13.3019 (2) Å | µ = 0.75 mm−1 |
V = 1015.23 (4) Å3 | T = 293 K |
Z = 4 | Prism, colourless |
F(000) = 424 | 0.30 × 0.20 × 0.15 mm |
Data collection top
Bruker SMART APEX CCD area-detector diffractometer | 1816 independent reflections |
Radiation source: fine-focus sealed tube | 1793 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.014 |
ω scans | θmax = 70.7°, θmin = 4.9° |
Absorption correction: multi-scan (SHELXTL; Bruker, 2003) | h = −5→6 |
Tmin = 0.795, Tmax = 0.895 | k = −14→14 |
5162 measured reflections | l = −16→15 |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.030 | w = 1/[σ2(Fo2) + (0.049P)2 + 0.0969P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.080 | (Δ/σ)max = 0.001 |
S = 1.06 | Δρmax = 0.16 e Å−3 |
1816 reflections | Δρmin = −0.14 e Å−3 |
185 parameters | Extinction correction: SHELXTL (Bruker, 2003), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0045 (7) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), with 720 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.0 (2) |
Crystal data top
C11H16O3 | V = 1015.23 (4) Å3 |
Mr = 196.24 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 6.1555 (2) Å | µ = 0.75 mm−1 |
b = 12.3990 (2) Å | T = 293 K |
c = 13.3019 (2) Å | 0.30 × 0.20 × 0.15 mm |
Data collection top
Bruker SMART APEX CCD area-detector diffractometer | 1816 independent reflections |
Absorption correction: multi-scan (SHELXTL; Bruker, 2003) | 1793 reflections with I > 2σ(I) |
Tmin = 0.795, Tmax = 0.895 | Rint = 0.014 |
5162 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.030 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.080 | Δρmax = 0.16 e Å−3 |
S = 1.06 | Δρmin = −0.14 e Å−3 |
1816 reflections | Absolute structure: Flack (1983), with 720 Friedel pairs |
185 parameters | Absolute structure parameter: 0.0 (2) |
0 restraints | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | −0.15801 (17) | 0.58118 (8) | −0.04022 (7) | 0.0501 (3) | |
O2 | −0.12023 (16) | 0.43031 (7) | 0.11624 (7) | 0.0449 (2) | |
O3 | −0.4441 (2) | 0.67943 (10) | −0.01049 (10) | 0.0680 (4) | |
C1 | 0.0480 (2) | 0.53461 (11) | −0.01040 (10) | 0.0426 (3) | |
H11 | 0.161 (3) | 0.5889 (14) | −0.0245 (12) | 0.045 (4)* | |
C2 | −0.2772 (2) | 0.64159 (11) | 0.02220 (11) | 0.0475 (3) | |
C3 | −0.2046 (2) | 0.65591 (10) | 0.12862 (11) | 0.0465 (3) | |
C4 | −0.3376 (4) | 0.70628 (15) | 0.19026 (15) | 0.0654 (5) | |
H42 | −0.480 (4) | 0.733 (2) | 0.1699 (18) | 0.092 (8)* | |
H41 | −0.309 (3) | 0.7139 (15) | 0.2594 (16) | 0.063 (5)* | |
C5 | 0.0115 (3) | 0.61033 (12) | 0.15846 (10) | 0.0467 (3) | |
H51 | 0.131 (3) | 0.6604 (14) | 0.1373 (12) | 0.050 (4)* | |
H52 | 0.023 (3) | 0.6017 (16) | 0.2326 (15) | 0.066 (5)* | |
C6 | 0.0537 (2) | 0.50583 (10) | 0.10142 (9) | 0.0392 (3) | |
C7 | 0.2744 (3) | 0.45541 (12) | 0.12449 (11) | 0.0480 (3) | |
H71 | 0.389 (3) | 0.5051 (13) | 0.1136 (11) | 0.047 (4)* | |
H72 | 0.278 (3) | 0.4355 (14) | 0.1958 (13) | 0.056 (5)* | |
C8 | 0.3210 (3) | 0.35796 (13) | 0.05820 (12) | 0.0553 (4) | |
H81 | 0.213 (3) | 0.2995 (14) | 0.0748 (11) | 0.049 (4)* | |
H82 | 0.470 (3) | 0.3294 (16) | 0.0729 (14) | 0.060 (5)* | |
C9 | 0.3071 (3) | 0.38754 (15) | −0.05291 (13) | 0.0623 (4) | |
H91 | 0.434 (3) | 0.4406 (17) | −0.0687 (15) | 0.067 (5)* | |
H92 | 0.326 (3) | 0.3235 (18) | −0.0949 (15) | 0.073 (6)* | |
C10 | 0.0871 (3) | 0.43784 (13) | −0.07732 (10) | 0.0533 (4) | |
H101 | 0.078 (3) | 0.4604 (14) | −0.1482 (14) | 0.059 (5)* | |
H102 | −0.036 (3) | 0.3874 (15) | −0.0651 (13) | 0.053 (4)* | |
C11 | −0.1582 (3) | 0.39879 (14) | 0.21747 (11) | 0.0598 (4) | |
H111 | −0.0256 | 0.3723 | 0.2463 | 0.093 (7)* | |
H112 | −0.2663 | 0.3430 | 0.2191 | 0.106 (8)* | |
H113 | −0.2083 | 0.4598 | 0.2553 | 0.128 (10)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0588 (6) | 0.0518 (5) | 0.0395 (4) | 0.0031 (5) | −0.0078 (4) | 0.0030 (4) |
O2 | 0.0498 (5) | 0.0459 (5) | 0.0389 (4) | −0.0085 (4) | 0.0001 (4) | 0.0046 (4) |
O3 | 0.0586 (8) | 0.0662 (7) | 0.0793 (8) | 0.0111 (6) | −0.0138 (6) | 0.0114 (6) |
C1 | 0.0481 (8) | 0.0419 (6) | 0.0377 (6) | −0.0035 (6) | −0.0006 (6) | 0.0029 (5) |
C2 | 0.0487 (8) | 0.0390 (6) | 0.0549 (8) | −0.0035 (6) | −0.0031 (6) | 0.0089 (6) |
C3 | 0.0539 (8) | 0.0351 (6) | 0.0504 (7) | −0.0058 (6) | 0.0032 (6) | 0.0007 (5) |
C4 | 0.0668 (13) | 0.0606 (9) | 0.0687 (11) | 0.0004 (8) | 0.0125 (9) | −0.0120 (8) |
C5 | 0.0567 (9) | 0.0441 (7) | 0.0392 (6) | −0.0027 (6) | −0.0058 (6) | −0.0041 (5) |
C6 | 0.0433 (7) | 0.0388 (6) | 0.0355 (6) | −0.0046 (5) | −0.0026 (5) | 0.0005 (5) |
C7 | 0.0477 (8) | 0.0485 (7) | 0.0475 (7) | −0.0011 (6) | −0.0046 (6) | 0.0004 (6) |
C8 | 0.0551 (10) | 0.0497 (8) | 0.0610 (9) | 0.0091 (7) | −0.0002 (7) | −0.0004 (7) |
C9 | 0.0727 (11) | 0.0584 (9) | 0.0556 (9) | 0.0085 (8) | 0.0143 (8) | −0.0078 (7) |
C10 | 0.0706 (10) | 0.0534 (8) | 0.0359 (6) | 0.0000 (8) | 0.0032 (7) | −0.0034 (6) |
C11 | 0.0642 (10) | 0.0652 (9) | 0.0499 (8) | −0.0034 (8) | 0.0074 (7) | 0.0149 (7) |
Geometric parameters (Å, º) top
O1—C2 | 1.3374 (18) | C4—H41 | 0.94 (2) |
O1—C1 | 1.4490 (17) | C5—H51 | 1.005 (18) |
O3—C2 | 1.2105 (19) | C5—H52 | 0.99 (2) |
C2—C3 | 1.495 (2) | C1—H11 | 0.986 (17) |
C3—C4 | 1.316 (2) | C7—H71 | 0.945 (17) |
O2—C11 | 1.4214 (16) | C7—H72 | 0.981 (17) |
O2—C6 | 1.4359 (16) | C8—H81 | 1.009 (18) |
C1—C10 | 1.513 (2) | C8—H82 | 1.00 (2) |
C1—C6 | 1.5300 (16) | C9—H91 | 1.04 (2) |
C6—C7 | 1.527 (2) | C9—H92 | 0.98 (2) |
C7—C8 | 1.523 (2) | C10—H101 | 0.985 (19) |
C3—C5 | 1.499 (2) | C10—H102 | 0.995 (18) |
C9—C10 | 1.526 (3) | C11—H111 | 0.9600 |
C8—C9 | 1.525 (2) | C11—H112 | 0.9600 |
C5—C6 | 1.5238 (18) | C11—H113 | 0.9600 |
C4—H42 | 0.98 (3) | | |
| | | |
C3···O3i | 3.035 (2) | C2···O3i | 3.025 (2) |
| | | |
C4—C3—C2 | 117.42 (16) | C8—C7—H71 | 106.8 (10) |
C4—C3—C5 | 124.46 (16) | C6—C7—H71 | 111.3 (10) |
C2—C3—C5 | 118.11 (12) | C8—C7—H72 | 110.8 (11) |
C11—O2—C6 | 115.59 (11) | C6—C7—H72 | 108.6 (11) |
O3—C2—O1 | 117.37 (14) | H71—C7—H72 | 107.1 (14) |
O3—C2—C3 | 123.21 (15) | C7—C8—C9 | 111.08 (14) |
O1—C2—C3 | 119.38 (12) | C7—C8—H81 | 108.6 (9) |
C2—O1—C1 | 122.23 (11) | C9—C8—H81 | 110.4 (9) |
O1—C1—C10 | 107.10 (12) | C7—C8—H82 | 109.9 (11) |
O1—C1—C6 | 112.27 (11) | C9—C8—H82 | 109.0 (11) |
C10—C1—C6 | 112.54 (11) | H81—C8—H82 | 107.8 (15) |
O1—C1—H11 | 107.1 (9) | C8—C9—C10 | 110.74 (14) |
C10—C1—H11 | 108.4 (9) | C8—C9—H91 | 107.7 (11) |
C6—C1—H11 | 109.2 (9) | C10—C9—H91 | 111.3 (11) |
C3—C4—H42 | 123.2 (15) | C8—C9—H92 | 110.6 (12) |
C3—C4—H41 | 122.7 (12) | C10—C9—H92 | 108.3 (12) |
H42—C4—H41 | 113.8 (18) | H91—C9—H92 | 108.2 (16) |
C3—C5—C6 | 109.88 (11) | C1—C10—C9 | 109.88 (14) |
C3—C5—H51 | 110.2 (10) | C1—C10—H101 | 109.2 (10) |
C6—C5—H51 | 105.1 (10) | C9—C10—H101 | 111.7 (11) |
C3—C5—H52 | 111.4 (11) | C1—C10—H102 | 106.3 (10) |
C6—C5—H52 | 113.0 (11) | C9—C10—H102 | 112.6 (10) |
H51—C5—H52 | 107.0 (15) | H101—C10—H102 | 107.0 (15) |
O2—C6—C5 | 111.04 (11) | O2—C11—H111 | 109.5 |
O2—C6—C7 | 111.64 (10) | O2—C11—H112 | 109.5 |
C5—C6—C7 | 113.57 (11) | H111—C11—H112 | 109.5 |
O2—C6—C1 | 105.58 (10) | O2—C11—H113 | 109.5 |
C5—C6—C1 | 106.37 (10) | H111—C11—H113 | 109.5 |
C7—C6—C1 | 108.13 (11) | H112—C11—H113 | 109.5 |
C8—C7—C6 | 112.10 (12) | | |
| | | |
C2—O1—C1—C6 | 32.16 (16) | C7—C8—C9—C10 | −55.4 (2) |
O1—C1—C6—C5 | −58.90 (14) | C6—C1—C10—C9 | −58.58 (17) |
C1—O1—C2—C3 | −4.28 (18) | C8—C9—C10—C1 | 56.06 (19) |
O1—C2—C3—C5 | 5.81 (18) | O1—C2—C3—C4 | −173.00 (14) |
C2—C3—C5—C6 | −34.72 (16) | O3—C2—C3—C5 | −176.61 (14) |
C3—C5—C6—C1 | 59.24 (15) | O1—C1—C10—C9 | 177.56 (11) |
C1—O1—C2—O3 | 178.00 (13) | C5—C6—C7—C8 | −173.95 (13) |
O3—C2—C3—C4 | 4.6 (2) | C10—C1—C6—C5 | −179.84 (13) |
C11—O2—C6—C5 | −60.00 (15) | C3—C5—C6—O2 | −55.14 (14) |
C11—O2—C6—C7 | 67.85 (15) | C3—C5—C6—C7 | 178.06 (11) |
C11—O2—C6—C1 | −174.88 (12) | C3—C5—C6—C1 | 59.24 (15) |
C10—C1—C6—O2 | −61.78 (15) | O1—C1—C6—O2 | 59.16 (13) |
C10—C1—C6—C7 | 57.84 (16) | C4—C3—C5—C6 | 144.00 (15) |
O2—C6—C7—C8 | 59.57 (15) | C2—O1—C1—C10 | 156.18 (12) |
C1—C6—C7—C8 | −56.15 (15) | O1—C1—C6—C7 | 178.78 (11) |
C6—C7—C8—C9 | 56.40 (19) | | |
Symmetry code: (i) x+1/2, −y+3/2, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H11···O3ii | 0.986 (17) | 2.683 (16) | 3.605 (2) | 156 (1) |
C5—H51···O3i | 1.005 (18) | 2.646 (17) | 3.278 (2) | 121 (1) |
Symmetry codes: (i) x+1/2, −y+3/2, −z; (ii) x+1, y, z. |
Experimental details
Crystal data |
Chemical formula | C11H16O3 |
Mr | 196.24 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 293 |
a, b, c (Å) | 6.1555 (2), 12.3990 (2), 13.3019 (2) |
V (Å3) | 1015.23 (4) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.75 |
Crystal size (mm) | 0.30 × 0.20 × 0.15 |
|
Data collection |
Diffractometer | Bruker SMART APEX CCD area-detector diffractometer |
Absorption correction | Multi-scan (SHELXTL; Bruker, 2003) |
Tmin, Tmax | 0.795, 0.895 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5162, 1816, 1793 |
Rint | 0.014 |
(sin θ/λ)max (Å−1) | 0.612 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.080, 1.06 |
No. of reflections | 1816 |
No. of parameters | 185 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.16, −0.14 |
Absolute structure | Flack (1983), with 720 Friedel pairs |
Absolute structure parameter | 0.0 (2) |
Selected geometric parameters (Å, º) topO1—C2 | 1.3374 (18) | C2—C3 | 1.495 (2) |
O1—C1 | 1.4490 (17) | C3—C4 | 1.316 (2) |
O3—C2 | 1.2105 (19) | | |
| | | |
C3···O3i | 3.035 (2) | C2···O3i | 3.025 (2) |
| | | |
C4—C3—C2 | 117.42 (16) | C2—C3—C5 | 118.11 (12) |
C4—C3—C5 | 124.46 (16) | | |
| | | |
C2—O1—C1—C6 | 32.16 (16) | O1—C2—C3—C5 | 5.81 (18) |
O1—C1—C6—C5 | −58.90 (14) | C2—C3—C5—C6 | −34.72 (16) |
C1—O1—C2—C3 | −4.28 (18) | C3—C5—C6—C1 | 59.24 (15) |
Symmetry code: (i) x+1/2, −y+3/2, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H11···O3ii | 0.986 (17) | 2.683 (16) | 3.605 (2) | 156 (1) |
C5—H51···O3i | 1.005 (18) | 2.646 (17) | 3.278 (2) | 121 (1) |
Symmetry codes: (i) x+1/2, −y+3/2, −z; (ii) x+1, y, z. |
The title compound, (I), represents a novel group of optically active α-methylene-δ-valerolactones synthesized in a highly stereoselective Michael reaction (Krawczyk & Śliwiński, 2003). Recently, we have reported the crystal structures of two compounds in the series, i.e. the 3-methylene-2-oxohexahydrochromene-4a-carboxylic acid ethyl ester, (II) (Krawczyk, Śliwiński, Wolf & Bodalski, 2004), and 4a-methyl-3-methyleneperhydrochromen-2-one, (III) (Krawczyk, Śliwiński & Wolf, 2004). A search of the Cambridge Structural Database (CSD, Version 5.26, November 2004 update; Allen, 2002) shows that the system in which the δ-valerolactone ring is condensed with the cyclohexene moiety along the individual Cd—Cg single bond [as in (I)–(III)] is unique among crystal structures examined to date.
A view of (I), with the atom-numbering scheme, is shown in Fig. 1. The δ-valerolactone and cyclohexane rings are almost coplanar with one another. The former ring adopts a half-chair conformation, with atoms O1, C1, C2, C3 and C5 almost coplanar and atom C6 situated at the flap. The main ring pseudo-symmetry element is a mirror plane passing through the endocyclic atoms C6 and C11. The three lowest ring asymmetry parameters (Griffin et al., 1984) are CS(C6) = 1.7 (1), C2(C5—C6) = 25.3 (2) and C2(C1—C6) = 28.8 (2)°. The cyclohexane ring exists in a chair conformation. The 4a-methoxy substituent and 8a-H atom occupy axial positions with respect to the cyclohexane ring. The molecule has two chiral centres at C1 and C6. Their absolute configurations are consistent with the reaction mechanism and are R and R, respectively.
The bond lengths in (I) (Table 1) are close to those observed in the similar compounds, (II) and (III). In particular, both exocyclic double bonds [O3═ C2 = 1.2105 (19) Å and C3═C4 = 1.316 (2) Å] are shorter than similar bonds observed in the O═C—C═C moiety [1.222 and 1.340 Å, respectively; Allen et al., 1992]. These bonds are separated by a relatively long C2—C3 bond [1.495 (2) Å; standard value 1.465 Å] and are not strictly coplanar, as shown by a non-zero value of the O3═C2—C3 ═C4 torsion angle [4.6 (2)°].
In the crystal of (I), the exocyclic carbonyl O3 atoms are involved in two kinds of intermolecular interactions, namely with atoms C2 and C3 of the O═ C—Ca═Cb moiety, and weak C—H···O hydrogen bonds (Steiner; 1997; Steiner & Desiraju, 1998) involving the axial atoms H11 and H51 of the δ-valerolactone ring (Fig. 2). The respective interatomic distances are given in Tables 2 and 3.
The simultaneous intermolecular interactions of the carbonyl O atom with the carbonyl C and Ca atoms of the O═C—Ca═Cb unsaturated system are uncommon among crystal structures examined to date. Only eight structures for which both intermolecular C···O distances are shorter than the sum of the respective van der Waals radii (3.22 Å; Bondi, 1964) are reported in the CSD. The most prominent examples are cuenicin acetate (Sen Gupta et al., 1986) and cordifene oxide (Steurer & Podlech, 2002).
Presumably, in (I), the intermolecular interactions follow from the prevailing electrostatic attraction of the negatively charged atom O3 (−0.64 e) with the positively charged carbonyl atom C2 (0.87 e). However, the origin of the second interaction, that between two negatively charged atoms O3 and C3 (−0.20 e), is unclear.