A Chiral N-Crotonyloxazolidinone Diels-Alder Adduct

Abstract

(4S)-4-Benzyl-3-[(4S,5S)-(1-methoxy-5-methylcyclohexen-4-yl) carbonyl]-2-oxazolidinone, C₁₉H₂₃NO₄, <i>M</i>,=329.40, monoclinic, <i>P</i>2₁, <i>a</i>=11.453(3), <i>b</i>=7.163(4), <i>c</i>=11.929(2)A, beta=111.86(2)^o, <i>V</i>=908.3(5)A³, <i>Z</i>=2, <i>D</i>x=1.20 g cm ^-3, wavelength(Mo <i>K</i>a)=0.71073/~, <i>u</i>=0.79 cm^-1, F(000)=352, <i>T</i>=297K, <i>R</i>=0.034 for 885 reflections with <i>F</i>₀² greater than 0. The molecule is extended in the crystal; there is a small twist, -13.1 (2)^o, about the amide-like C--N bond joining the oxazolidinone ring to the carbonyl group. The configurations at the two optical centers in the cyclohexene ring confirm the anticipated stereospecificity of the Diels-Alder cycloaddition synthesis.