Diastereoselective synthesis of α-bromo amides leading to diastereomerically enriched α-amino-, α-hydroxy- and α-thiocarboxylic acid derivatives

Abstract

α-Bromo amides derived from Oppolzer's camphorsultam can be prepared diastereoselectively starting from racemic α-bromo acids, and undergo epimerisation under appropriate conditions leading to an enhanced d.e.. By reacting the individual isomers or the mixture of diastereoisomers with a suitable nucleophile it is possible to obtain α-substituted carboxylic acids, including α-amino- α-hydroxy- and α-thiocarboxylic acid derivatives, in diastereomerically enriched form.