Poly-L-leucine catalysed epoxidation reactions:: A short, stereoselective route to chiral α,β-epoxyalcohols

Grignard alkylation of epoxyketones (1), (4) from Poly-L-leucine catalysed asymmetric epoxidation of alpha,beta-unsaturated ketones provides a short, stereocontrolled route to optically pure alpha,beta-epoxy tertiary alcohols (2), (3). These epoxyalcohols undergo Payne rearrangement in mild Lewis acid conditions to give the isomeric alpha,beta-epoxy secondary alcohols (5), (6). Alternatively, the epoxide may be opened up in a highly regio-and stereospecific manner to give polysubstituted 1-chloro-2,3-diols (7), (8). (C) 1998 Elsevier Science Ltd. All rights reserved.