organic compounds
Ethyl (4aR*,7S*,8S*,8aS*)-1-oxo-7-phenyl-3,4,4a,7,8,8a-hexahydro-1H-isochromene-8-carboxylate
aLaboratory of Asymmetric Catalysis and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, People's Republic of China
*Correspondence e-mail: wyz@zju.edu.cn
In the title compound, C18H20O4, both the tetrahydropyranone ring and the cyclohexene ring adopt envelope conformations. The crystal packing is stabilized by weak intermolecular C—H⋯O hydrogen bonding.
Related literature
The title compound is a derivative of 1-oxo-hexahydro-1H-isochromene, which has been reported as a key intermediate towards the total syntheses of natural products such as eleutherobin and tetronothiodin, see: Kim et al. (2000); Jung et al. (2000); Page et al. (2003). For microwave-assisted intramolecular Diels–Alder cycloaddition, see: Wu et al. (2006, 2007); Wang et al. (2009).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: PROCESS-AUTO (Rigaku, 1998); cell PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S1600536810017009/xu2757sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810017009/xu2757Isup2.hkl
A 10 mL pressured process vial was charged ethyl (3E,5E)-6-phenylhexa-3,5-dien-1-yl fumarate (172.0 mg, 0.57 mmol) followed by adding MeCN (4 mL). The loaded vial was then sealed with a cap containing a silicon septum and put into the cavity of a technical microwave reactor with the temperature measured by an IR sensor. After heating at 453 K for 1 h, the reaction mixture was concentrated under reduced pressure. The residue was purified by flash
(silica gel, 20% EtOAc in petroleum ether) to furnish the title compound (95.0 mg, 52%), along with a minor diastereomer (32.0 mg, 19%), as colorless needles. mp 392-394 K (EtOAc-hexane). Single crystals, as a racemate, suitable for X-ray diffraction of the title compound were grown at ambient temperature in the mixed solvent of ethyl acetate and hexane (v:v = 10:1).H atoms were placed in calculated positions with C—H = 0.93-0.98 Å, and refined in riding model with Uiso(H) = 1.5Ueq(C) for methyl and 1.2Ueq(C) for the others.
The title compound, C18H20O4, refers to the derivative of 1-oxo- hexahydro-1H-isochromenes, which has been reported as a key intermediate towards total syntheses of natural products such as eleutherobin (Kim et al., 2000; Jung et al., 2000) and tetronothiodin (Page et al., 2003). The title compound has recently been obtained during microwave-assisted intramolecular Diels-Alder
along with a minor diastereomer with a 74:26 (Wu et al., 2006, 2007; Wang et al., 2009). The compound has four stereogenic centers but crystallizes as a racemate as indicated by the centrosymmetric We report here its crystal structure.In the molecular structure of the title compound (Fig. 1), there are one pyranone ring and one cyclohexene ring. Both of the two rings C1-C2/C6-C9 and C2-C3/O2/C4-C6 adopt
The crystal packing is stabilized by weak non-classical intermolecular C—H···O hydrogen bonds (Table 1).The title compound is a derivative of 1-oxo-hexahydro-1H-isochromene, which has been reported as a key intermediate towards the total syntheses of natural products such as eleutherobin and tetronothiodin, see: Kim et al. (2000); Jung et al. (2000); Page et al. (2003). For microwave-assisted intramolecular Diels–Alder
see: Wu et al. (2006, 2007); Wang et al. (2009).Data collection: PROCESS-AUTO (Rigaku, 1998); cell
PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).C18H20O4 | F(000) = 1280 |
Mr = 300.34 | Dx = 1.223 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 12675 reflections |
a = 15.5513 (12) Å | θ = 3.1–27.4° |
b = 9.9178 (7) Å | µ = 0.09 mm−1 |
c = 21.1542 (17) Å | T = 296 K |
V = 3262.7 (4) Å3 | Needle, colorless |
Z = 8 | 0.36 × 0.16 × 0.14 mm |
Rigaku R-AXIS RAPID IP diffractometer | 1627 reflections with I > 2σ(I) |
Radiation source: rolling anode | Rint = 0.075 |
Graphite monochromator | θmax = 26.0°, θmin = 3.1° |
Detector resolution: 10.00 pixels mm-1 | h = −19→19 |
ω scans | k = −11→12 |
26140 measured reflections | l = −26→26 |
3200 independent reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.069 | H-atom parameters constrained |
wR(F2) = 0.197 | w = 1/[σ2(Fo2) + (0.0698P)2 + 1.9409P] where P = (Fo2 + 2Fc2)/3 |
S = 1.00 | (Δ/σ)max < 0.001 |
3200 reflections | Δρmax = 0.35 e Å−3 |
202 parameters | Δρmin = −0.28 e Å−3 |
1 restraint | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0067 (12) |
C18H20O4 | V = 3262.7 (4) Å3 |
Mr = 300.34 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 15.5513 (12) Å | µ = 0.09 mm−1 |
b = 9.9178 (7) Å | T = 296 K |
c = 21.1542 (17) Å | 0.36 × 0.16 × 0.14 mm |
Rigaku R-AXIS RAPID IP diffractometer | 1627 reflections with I > 2σ(I) |
26140 measured reflections | Rint = 0.075 |
3200 independent reflections |
R[F2 > 2σ(F2)] = 0.069 | 1 restraint |
wR(F2) = 0.197 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.35 e Å−3 |
3200 reflections | Δρmin = −0.28 e Å−3 |
202 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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. |
x | y | z | Uiso*/Ueq | ||
O3 | 0.16345 (14) | 0.3940 (2) | 0.39009 (15) | 0.1040 (10) | |
C17 | 0.0706 (3) | 0.3651 (6) | 0.3998 (3) | 0.146 (2) | |
H17A | 0.0524 | 0.2860 | 0.3764 | 0.175* | |
H17B | 0.0350 | 0.4414 | 0.3880 | 0.175* | |
C18 | 0.0687 (4) | 0.3407 (8) | 0.4701 (3) | 0.205 (3) | |
H18A | 0.0993 | 0.2591 | 0.4796 | 0.308* | |
H18B | 0.0102 | 0.3325 | 0.4839 | 0.308* | |
H18C | 0.0955 | 0.4150 | 0.4915 | 0.308* | |
O4 | 0.18555 (14) | 0.1796 (2) | 0.36346 (12) | 0.0848 (8) | |
C1 | 0.30154 (17) | 0.3380 (3) | 0.35293 (14) | 0.0588 (8) | |
H1 | 0.3083 | 0.4330 | 0.3645 | 0.071* | |
C9 | 0.36348 (18) | 0.2519 (3) | 0.39280 (14) | 0.0642 (8) | |
H9 | 0.3484 | 0.1571 | 0.3860 | 0.077* | |
C16 | 0.21088 (19) | 0.2931 (3) | 0.36799 (15) | 0.0660 (8) | |
C10 | 0.35139 (19) | 0.2824 (3) | 0.46291 (15) | 0.0680 (8) | |
C8 | 0.4540 (2) | 0.2708 (3) | 0.37126 (18) | 0.0765 (9) | |
H8 | 0.4978 | 0.2486 | 0.3993 | 0.092* | |
O2 | 0.27531 (18) | 0.5007 (3) | 0.20646 (13) | 0.1045 (9) | |
C2 | 0.32050 (19) | 0.3207 (3) | 0.28126 (15) | 0.0704 (9) | |
H2 | 0.3127 | 0.2249 | 0.2714 | 0.084* | |
C5 | 0.4213 (2) | 0.5048 (4) | 0.24889 (18) | 0.0856 (10) | |
H5A | 0.4050 | 0.5586 | 0.2853 | 0.103* | |
H5B | 0.4803 | 0.5264 | 0.2381 | 0.103* | |
C7 | 0.4757 (2) | 0.3170 (4) | 0.31524 (19) | 0.0837 (11) | |
H7 | 0.5340 | 0.3258 | 0.3065 | 0.100* | |
C6 | 0.4140 (2) | 0.3561 (3) | 0.26494 (16) | 0.0730 (9) | |
H6 | 0.4293 | 0.3053 | 0.2268 | 0.088* | |
C15 | 0.3062 (2) | 0.1947 (4) | 0.50117 (18) | 0.0838 (10) | |
H15 | 0.2835 | 0.1159 | 0.4842 | 0.101* | |
C3 | 0.2542 (3) | 0.3978 (4) | 0.24313 (18) | 0.0886 (11) | |
O1 | 0.17953 (19) | 0.3714 (4) | 0.24613 (17) | 0.1447 (14) | |
C11 | 0.3852 (2) | 0.3990 (4) | 0.48850 (19) | 0.0886 (11) | |
H11 | 0.4150 | 0.4592 | 0.4629 | 0.106* | |
C14 | 0.2948 (3) | 0.2231 (6) | 0.5638 (2) | 0.1138 (14) | |
H14 | 0.2636 | 0.1641 | 0.5891 | 0.137* | |
C13 | 0.3294 (4) | 0.3388 (7) | 0.5899 (2) | 0.1200 (16) | |
H13 | 0.3222 | 0.3572 | 0.6326 | 0.144* | |
C4 | 0.3635 (3) | 0.5372 (5) | 0.1941 (2) | 0.1098 (14) | |
H4A | 0.3666 | 0.6330 | 0.1853 | 0.132* | |
H4B | 0.3835 | 0.4893 | 0.1570 | 0.132* | |
C12 | 0.3746 (3) | 0.4264 (5) | 0.5521 (2) | 0.1144 (15) | |
H12 | 0.3982 | 0.5043 | 0.5693 | 0.137* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O3 | 0.0557 (13) | 0.0768 (15) | 0.179 (3) | −0.0037 (11) | 0.0323 (15) | −0.0228 (16) |
C17 | 0.095 (3) | 0.127 (4) | 0.216 (7) | −0.015 (3) | 0.045 (4) | −0.020 (4) |
C18 | 0.146 (6) | 0.258 (8) | 0.211 (8) | −0.069 (5) | 0.052 (5) | 0.007 (7) |
O4 | 0.0728 (15) | 0.0589 (13) | 0.123 (2) | −0.0162 (11) | −0.0052 (13) | −0.0008 (12) |
C1 | 0.0494 (15) | 0.0527 (15) | 0.074 (2) | −0.0019 (13) | 0.0044 (14) | −0.0056 (14) |
C9 | 0.0597 (17) | 0.0526 (15) | 0.080 (2) | 0.0045 (14) | 0.0024 (16) | −0.0035 (15) |
C16 | 0.0563 (17) | 0.0572 (17) | 0.084 (2) | −0.0022 (14) | −0.0007 (16) | 0.0004 (16) |
C10 | 0.0599 (18) | 0.0660 (19) | 0.078 (2) | 0.0079 (15) | −0.0042 (16) | −0.0010 (17) |
C8 | 0.0546 (18) | 0.079 (2) | 0.096 (3) | 0.0106 (16) | 0.0022 (18) | −0.0019 (19) |
O2 | 0.095 (2) | 0.116 (2) | 0.103 (2) | −0.0024 (16) | −0.0076 (15) | 0.0319 (17) |
C2 | 0.068 (2) | 0.0661 (18) | 0.077 (2) | −0.0033 (16) | 0.0021 (16) | −0.0063 (16) |
C5 | 0.077 (2) | 0.083 (2) | 0.096 (3) | −0.0076 (19) | 0.018 (2) | −0.002 (2) |
C7 | 0.0534 (19) | 0.091 (2) | 0.106 (3) | 0.0064 (17) | 0.0163 (19) | −0.010 (2) |
C6 | 0.068 (2) | 0.074 (2) | 0.077 (2) | 0.0017 (16) | 0.0155 (17) | −0.0103 (17) |
C15 | 0.081 (2) | 0.092 (2) | 0.078 (2) | 0.003 (2) | 0.0015 (19) | 0.011 (2) |
C3 | 0.078 (2) | 0.106 (3) | 0.083 (2) | −0.007 (2) | −0.010 (2) | 0.010 (2) |
O1 | 0.0751 (19) | 0.195 (3) | 0.164 (3) | −0.024 (2) | −0.0326 (19) | 0.072 (3) |
C11 | 0.096 (3) | 0.078 (2) | 0.092 (3) | −0.001 (2) | −0.003 (2) | −0.015 (2) |
C14 | 0.111 (3) | 0.133 (4) | 0.098 (4) | 0.009 (3) | 0.005 (3) | 0.022 (3) |
C13 | 0.127 (4) | 0.155 (5) | 0.078 (3) | 0.037 (4) | 0.003 (3) | −0.012 (3) |
C4 | 0.099 (3) | 0.111 (3) | 0.119 (3) | −0.008 (3) | 0.014 (3) | 0.028 (3) |
C12 | 0.128 (4) | 0.109 (3) | 0.106 (4) | 0.014 (3) | −0.015 (3) | −0.031 (3) |
O3—C16 | 1.327 (4) | C2—C3 | 1.516 (5) |
O3—C17 | 1.486 (5) | C2—C6 | 1.535 (4) |
C17—C18 | 1.507 (8) | C2—H2 | 0.9800 |
C17—H17A | 0.9700 | C5—C4 | 1.501 (5) |
C17—H17B | 0.9700 | C5—C6 | 1.518 (5) |
C18—H18A | 0.9600 | C5—H5A | 0.9700 |
C18—H18B | 0.9600 | C5—H5B | 0.9700 |
C18—H18C | 0.9600 | C7—C6 | 1.485 (5) |
O4—C16 | 1.197 (3) | C7—H7 | 0.9300 |
C1—C16 | 1.512 (4) | C6—H6 | 0.9800 |
C1—C9 | 1.539 (4) | C15—C14 | 1.367 (6) |
C1—C2 | 1.554 (4) | C15—H15 | 0.9300 |
C1—H1 | 0.9800 | C3—O1 | 1.192 (4) |
C9—C8 | 1.491 (4) | C11—C12 | 1.382 (6) |
C9—C10 | 1.525 (4) | C11—H11 | 0.9300 |
C9—H9 | 0.9800 | C14—C13 | 1.382 (7) |
C10—C15 | 1.379 (5) | C14—H14 | 0.9300 |
C10—C11 | 1.381 (4) | C13—C12 | 1.374 (6) |
C8—C7 | 1.314 (4) | C13—H13 | 0.9300 |
C8—H8 | 0.9300 | C4—H4A | 0.9700 |
O2—C3 | 1.323 (4) | C4—H4B | 0.9700 |
O2—C4 | 1.442 (5) | C12—H12 | 0.9300 |
C16—O3—C17 | 116.3 (3) | C1—C2—H2 | 106.9 |
O3—C17—C18 | 100.7 (4) | C4—C5—C6 | 109.6 (3) |
O3—C17—H17A | 111.6 | C4—C5—H5A | 109.7 |
C18—C17—H17A | 111.6 | C6—C5—H5A | 109.7 |
O3—C17—H17B | 111.6 | C4—C5—H5B | 109.7 |
C18—C17—H17B | 111.6 | C6—C5—H5B | 109.7 |
H17A—C17—H17B | 109.4 | H5A—C5—H5B | 108.2 |
C17—C18—H18A | 109.5 | C8—C7—C6 | 124.8 (3) |
C17—C18—H18B | 109.5 | C8—C7—H7 | 117.6 |
H18A—C18—H18B | 109.5 | C6—C7—H7 | 117.6 |
C17—C18—H18C | 109.5 | C7—C6—C5 | 111.5 (3) |
H18A—C18—H18C | 109.5 | C7—C6—C2 | 113.0 (3) |
H18B—C18—H18C | 109.5 | C5—C6—C2 | 110.1 (3) |
C16—C1—C9 | 107.8 (2) | C7—C6—H6 | 107.3 |
C16—C1—C2 | 110.5 (2) | C5—C6—H6 | 107.3 |
C9—C1—C2 | 110.8 (2) | C2—C6—H6 | 107.3 |
C16—C1—H1 | 109.3 | C14—C15—C10 | 120.4 (4) |
C9—C1—H1 | 109.3 | C14—C15—H15 | 119.8 |
C2—C1—H1 | 109.3 | C10—C15—H15 | 119.8 |
C8—C9—C10 | 112.9 (3) | O1—C3—O2 | 116.3 (4) |
C8—C9—C1 | 110.7 (3) | O1—C3—C2 | 121.5 (4) |
C10—C9—C1 | 110.2 (2) | O2—C3—C2 | 122.2 (3) |
C8—C9—H9 | 107.6 | C10—C11—C12 | 120.0 (4) |
C10—C9—H9 | 107.6 | C10—C11—H11 | 120.0 |
C1—C9—H9 | 107.6 | C12—C11—H11 | 120.0 |
O4—C16—O3 | 123.6 (3) | C15—C14—C13 | 120.5 (5) |
O4—C16—C1 | 124.5 (3) | C15—C14—H14 | 119.8 |
O3—C16—C1 | 111.8 (2) | C13—C14—H14 | 119.8 |
C15—C10—C11 | 119.4 (3) | C12—C13—C14 | 119.5 (4) |
C15—C10—C9 | 120.6 (3) | C12—C13—H13 | 120.3 |
C11—C10—C9 | 120.0 (3) | C14—C13—H13 | 120.3 |
C7—C8—C9 | 124.2 (3) | O2—C4—C5 | 112.1 (3) |
C7—C8—H8 | 117.9 | O2—C4—H4A | 109.2 |
C9—C8—H8 | 117.9 | C5—C4—H4A | 109.2 |
C3—O2—C4 | 122.4 (3) | O2—C4—H4B | 109.2 |
C3—C2—C6 | 114.1 (3) | C5—C4—H4B | 109.2 |
C3—C2—C1 | 109.5 (3) | H4A—C4—H4B | 107.9 |
C6—C2—C1 | 112.0 (2) | C13—C12—C11 | 120.2 (4) |
C3—C2—H2 | 106.9 | C13—C12—H12 | 119.9 |
C6—C2—H2 | 106.9 | C11—C12—H12 | 119.9 |
C16—O3—C17—C18 | 100.1 (5) | C8—C7—C6—C2 | −7.3 (5) |
C16—C1—C9—C8 | 168.7 (2) | C4—C5—C6—C7 | 175.1 (3) |
C2—C1—C9—C8 | 47.7 (3) | C4—C5—C6—C2 | −58.7 (4) |
C16—C1—C9—C10 | −65.7 (3) | C3—C2—C6—C7 | 160.7 (3) |
C2—C1—C9—C10 | 173.3 (2) | C1—C2—C6—C7 | 35.6 (4) |
C17—O3—C16—O4 | −9.7 (6) | C3—C2—C6—C5 | 35.4 (4) |
C17—O3—C16—C1 | 173.5 (3) | C1—C2—C6—C5 | −89.8 (3) |
C9—C1—C16—O4 | −55.5 (4) | C11—C10—C15—C14 | 0.1 (5) |
C2—C1—C16—O4 | 65.7 (4) | C9—C10—C15—C14 | −179.3 (3) |
C9—C1—C16—O3 | 121.3 (3) | C4—O2—C3—O1 | −174.7 (4) |
C2—C1—C16—O3 | −117.5 (3) | C4—O2—C3—C2 | 7.5 (6) |
C8—C9—C10—C15 | −133.0 (3) | C6—C2—C3—O1 | 172.4 (4) |
C1—C9—C10—C15 | 102.6 (3) | C1—C2—C3—O1 | −61.2 (5) |
C8—C9—C10—C11 | 47.5 (4) | C6—C2—C3—O2 | −9.9 (5) |
C1—C9—C10—C11 | −76.9 (4) | C1—C2—C3—O2 | 116.5 (4) |
C10—C9—C8—C7 | −144.6 (3) | C15—C10—C11—C12 | 0.9 (5) |
C1—C9—C8—C7 | −20.5 (4) | C9—C10—C11—C12 | −179.7 (3) |
C16—C1—C2—C3 | 56.2 (3) | C10—C15—C14—C13 | −1.0 (6) |
C9—C1—C2—C3 | 175.6 (3) | C15—C14—C13—C12 | 0.8 (7) |
C16—C1—C2—C6 | −176.1 (2) | C3—O2—C4—C5 | −31.0 (5) |
C9—C1—C2—C6 | −56.7 (3) | C6—C5—C4—O2 | 56.5 (4) |
C9—C8—C7—C6 | −0.5 (6) | C14—C13—C12—C11 | 0.2 (7) |
C8—C7—C6—C5 | 117.3 (4) | C10—C11—C12—C13 | −1.0 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1···O4i | 0.98 | 2.45 | 3.401 (4) | 164 |
C5—H5A···O4i | 0.97 | 2.48 | 3.412 (4) | 161 |
C7—H7···O1ii | 0.93 | 2.56 | 3.468 (5) | 165 |
C13—H13···O2iii | 0.93 | 2.59 | 3.356 (6) | 140 |
Symmetry codes: (i) −x+1/2, y+1/2, z; (ii) x+1/2, y, −z+1/2; (iii) −x+1/2, −y+1, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C18H20O4 |
Mr | 300.34 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 296 |
a, b, c (Å) | 15.5513 (12), 9.9178 (7), 21.1542 (17) |
V (Å3) | 3262.7 (4) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.36 × 0.16 × 0.14 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID IP |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 26140, 3200, 1627 |
Rint | 0.075 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.069, 0.197, 1.00 |
No. of reflections | 3200 |
No. of parameters | 202 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.35, −0.28 |
Computer programs: PROCESS-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1···O4i | 0.98 | 2.45 | 3.401 (4) | 164 |
C5—H5A···O4i | 0.97 | 2.48 | 3.412 (4) | 161 |
C7—H7···O1ii | 0.93 | 2.56 | 3.468 (5) | 165 |
C13—H13···O2iii | 0.93 | 2.59 | 3.356 (6) | 140 |
Symmetry codes: (i) −x+1/2, y+1/2, z; (ii) x+1/2, y, −z+1/2; (iii) −x+1/2, −y+1, z+1/2. |
Acknowledgements
This work is supported by the Natural Science Foundation of China (grant No. 20572092). Professor Wei-Min Dai is thanked for his valuable suggestions on this work. Mr Jianming Gu of the X-ray crystallography facility of Zhejiang University is acknowledged for his assistance with the analysis.
References
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Jung, M. E., Huang, A. & Johnson, T. W. (2000). Org. Lett. 2, 1835–1837. Web of Science CrossRef PubMed CAS Google Scholar
Kim, P., Nantz, M. H., Kurth, M. J. & Olmstead, M. M. (2000). Org. Lett. 2, 1831–1834. Web of Science CrossRef PubMed CAS Google Scholar
Page, P. C. B., Vahedi, H., Batchelor, K. J., Hindley, S. J., Edgar, M. & Beswick, P. (2003). Synlett, pp. 1022–1024. Web of Science CrossRef Google Scholar
Rigaku (1998). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku/MSC (2002). CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wang, Y., Wu, J. & Dai, W.-M. (2009). Synlett, pp. 2862–2866. Google Scholar
Wu, J., Sun, L. & Dai, W.-M. (2006). Tetrahedron, 62, 8360–8372. Web of Science CSD CrossRef CAS Google Scholar
Wu, J., Yu, H., Wang, Y., Xing, X. & Dai, W.-M. (2007). Tetrahedron Lett. 48, 6543–6547. Web of Science CSD CrossRef CAS Google Scholar
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The title compound, C18H20O4, refers to the derivative of 1-oxo- hexahydro-1H-isochromenes, which has been reported as a key intermediate towards total syntheses of natural products such as eleutherobin (Kim et al., 2000; Jung et al., 2000) and tetronothiodin (Page et al., 2003). The title compound has recently been obtained during microwave-assisted intramolecular Diels-Alder cycloaddition along with a minor diastereomer with a 74:26 diastereomeric ratio (Wu et al., 2006, 2007; Wang et al., 2009). The compound has four stereogenic centers but crystallizes as a racemate as indicated by the centrosymmetric space group. We report here its crystal structure.
In the molecular structure of the title compound (Fig. 1), there are one pyranone ring and one cyclohexene ring. Both of the two rings C1-C2/C6-C9 and C2-C3/O2/C4-C6 adopt envelope conformation. The crystal packing is stabilized by weak non-classical intermolecular C—H···O hydrogen bonds (Table 1).