Asymmetric Diels-Alder reactions employing modified camphor-derived oxazolidin-2-one chiral auxiliaries

Article abstract of DOI:10.1016/S0040-4020(96)00070-1

Transposition of the dormant methyl group from C-1 in chiral oxazolidin-2-one 2 to C-7 in a six step synthetic sequence from (1R)-camphore 5 creates a novel transfigomer 4 with sufficient π-topological bias to induce excellent levels of asymmetric induction in Lewis-acid catalysed Diels-Alder reactions of its α, β-unsaturated carboximide derivatives with cyclopentadiene. Further modification of 4 by replacement of the C-7 methyl group with an ethyl substituent raises the level of diastereoselectivity for the acrylate derivative 11a from 81 to > 95% d.e..