Carbohydrate auxiliaries in stereoselective synthese of decahydroquinoline alkaloids

摘要

Using tetrs-O-pivaloyl-#beta#-D-galactopyranosylamine as the chiral auziliary,both trans- and cis-annelated decahydroquinoline alkaloids can be synthesized stereoselective.This methodology of asymmetric synthesis is based on the effect that both enantiomers of 2,6-disubstituted piperidin-4-ones are selectively and alternatively accessible using the auxiliary as the identical stereodifferentiation tool.In addition,the carbohydrate auxiliary controls the stereoselective protonation of enolates formed by conjugate addition of suprates to N-galactosyl octahydroquinolin-4-ones.The syntheses of trans-4a-epi-pumiliotoxin C and cis-4a-epi-perhydro-219A illustrate this concept of asymmetric synthesis of decahydroquinoline alkaloids.