A General,Convergent Strategy for the Construction of Indolizidine Alkaloids: Total Syntheses of (-)-Indolizidine 223AB and Alkaloid (-)-205B

摘要

N-Toluenesulfonyl aziridines comprise effective second electrophiles in the solvent controlled three-component linchpin union of silyl dithianes for the stereocontrolled convergent elaboration of protected 1,5-amino alcohols.This tactic,in conjunction with a one-flask sequential cyclization,constitutes an effective general strategy for the construction of indolizidine and related alkaloids,illustrated here with the total syntheses of (-)-indolizidine 223AB (1) and alkaloid (-)-205B (2).