Stereoselective Synthesis of all Stereoisomeric 2-Amino-3-hydroxy-4- phenylbutanolides.

Abstract Diastereoselective methylation of the ketone 5a leads to the anti-derivative 4a ; the other diastereoisomer 4b may be obtained by a deprotonation/reprotonation sequence. Each of the methylated products may be reduced stereoselectively in either sense by appropriate choice of reagent, providing a route to all stereoisomers of the title 2-amino-3-hydroxy-4-phenylbutanolides 10a–d . © 1997 Elsevier Science Ltd.