STEREOSELECTIVE SYNTHESIS OF BIOLOGICALLY-ACTIVE TETRONIC ACIDS

(4R)-3-Amino-4-trimethylsilyloxy-2-alkenoates (R)-3, obtained from O-t rimethylsilyl protected optically active cyanohydrins (R)-1 via the Bl aise reaction, are hydrolyzed under mildly acidic conditions to give o ptically active tetronic acids (R)-4 without racemization. From the fo llow-up reactions of (R)-4 investigated, only methylation with diazome thane afforded the biologically active tetronic acid derivative (R)-5a without racemization whereas acylation and reductive alkylation, resp ectively, resulted in partial racemization or failed on the whole. (C) 1998 Elsevier Science Ltd. All rights reserved.