Catalysis in water:: Synthesis of β-amino amides by Sc(III) promoted condensation of silylketene pyridylthioacetal and imines

The scandium (III) catalysed condensation of silylketene thioacetals and pyridylthioacetals with imines in pure water was studied. The reaction of the phenylthioacetal derivatives brings always to beta-aminoesters; the reaction of pyridylthioacetals leads to the stereoselective formation of beta-lactams in organic solvents, while in the presence of a large amount of water affords beta-amino amides in good yields. That represents a new, easy, one-pot catalytic synthesis in water of an interesting class of compounds, direct precursors of 1,3-diamino hydroxy compounds. The possibility of recovering and recycling the catalytic systems was also briefly investigated. (C) 2007 Elsevier B.V. All rights reserved.