摘要:
A simple route was developed for the synthesis of optically enriched beta-amino-alpha-keto amides. The highly diastereoselective addition of alkyl dithiolanecarboxylates to optically enriched sulfinimines affords the corresponding beta-amino-alpha-keto esters in which the ketone carbonyl group is protected as a dithiolane. Amidation of the ester functionality with a primary amine proceeds readily at room temperature. Treatment with HCl cleaves the N-S bond of the sulfinyl group to provide a free amine functionality, which can then be incorporated into a peptide. Removal of the dithiolane protecting group under oxidative conditions proceeds without epimerization as exemplified by a model dipeptide. (C) 2010 Elsevier Ltd. All rights reserved.