摘要:
The Michael addition of R2CuLi or R2CuMgBr to 4-phenyl-3,4,7,8-tetrahydro-6H-pyrido (2,1-c)(1,4)oxazin-1-one 2, readily obtained from 2-cyano-6-phenyloxazolopiperidine 1, led to the formation of alkylated lactones 4a-d in high yield and with complete diastereoselectivity. Transformation of lactones 4a-d to 3-alkyl pipecolic acids was achieved by simple hydrogenolysis. (C) 1999 Elsevier Science Ltd. All rights reserved.