Asymmetric synthesis of cis-4,5-disubstituted oxazolidin-2-ones via chiral a-amino epoxides derived from L-Serine

Oxazolidine moieties are widely recognized as very useful chiral auxiliaries in asymmetric reactions,1 and chiral epoxides have been frequently involved in the design of strategies for the achievement of stereocontrol.2 However, only few examples reported in literature,3 combine the influence in the same substrate of both epoxide and oxazolidine moieties, although in any case related with intramolecular reactions. As a part of our ongoing research program aimed at the synthesis of biologically relevant hydroxylated amino acids,4 we wish to report an easy strategy which allows the stereoselective preparation of 4,5-disubstituted oxazolidinones 5, based on the use of the homochiral epoxy oxazolidines derived from L-Serine, which could be precursors of b,gdihydroxy- a-amino acids (Scheme 1).