ENANTIOPURE ALPHA-HYDROXY-BETA-LACTAMS VIA STEREOSELECTIVE GLYCOSYLATION

Stereospecific glycosylation via the Ferrier rearrangement catalyzed b y iodine has been used to obtain both enantiomers of a trans 4-aryl-3- hydroxy-2-azetidinone. Unexpectedly, a rhamnal derivative had to be em ployed for this reaction since a glucal derivative failed to work. Thi s synthesis complements our previously described preparation of the co rresponding cis isomers by the same methodology. Thus, convenient acce ss has become available to all four homochiral stereoisomers of alpha- hydroxy-beta-lactams some of which are synthons for Taxol(R) and analo gs. (C) 1997 Elsevier Science Ltd.