摘要:
The Lewis acid promoted cyclisation of N-substituted-4-formyloxyazetidin-2-one easily available from 4-vinyloxyazetidin-2-one is described. The efficiency of the ring closure reaction, to give 1-oxacephams, depends on the oxygen protected-activated group and the Lewis acid. (C) 1998 Elsevier Science Ltd. All rights reserved.