ASYMMETRIC SYNTHESIS OF p-LACTAMS BY THE STAUDINGER REACTION

摘要

The authors are grateful to Universidad del Pais Vasco UPV/EHU (UFI 11/22) Gobierno Vasco (Grant IT628-13), and Ministerio de Economia y Competitividad (Grant CTQ2013-47925-C2-1P), Spain, for continuous financial support. The formal [2 + 2] cycloaddition of imines with ketenes to afford P-lactams (2-azetidinones) is termed the Staudinger reaction. Although originally discovered using an isolated ketene,1 the instability of these reagents often precludes their iso-lation. The reaction, therefore, more commonly involves the formation of p-lactams from imines and in situ generated ketenes, usually formed from an acid chloride or other activated acid derivative plus a tertiary amine base, as shown in Scheme 1.