S(N)2 ' regio and stereoselective alkylation of allylic mesylates linked to a N-Boc oxzolidine using organocuprates

N-Boc-oxazolidines bearing an allylic alcohol chain were transformed into t heir mesylate derivatives. A regio and stereoselective 1,3-transfer of chir ality was effected on these mesylates during their alkylation by mean of or ganocuprate additions The resulting N-Boc-2-alkenyl oxazolidines undergo an intramolecular bromocarbamoylation with a high level of stereocontrol upon treatment with NBS and afford, after treatment with sodium ethoxide, the c orresponding epoxy oxazolidines. The overall methodology allows an efficien t control for the formation of three contiguous chiral centers. (C) 1999 El sevier Science Ltd. All rights reserved.