Base Promoted 5-endo-dig cyclization: A Facile Approach Towards Pyrrolizidine Core

Abstract

Pyrrolizidine scaffolds are having many biological activities in plants as well as in human body; hence these scaffolds are of great interest on synthetic perspectives. A base facilitated 5-endo-dig cyclization strategy has been developed to obtain the pyrrolizidine scaffold. This protocol allowed us to approach a diverse range of alkyl and aryl substituted pyrrolizidine scaffolds in moderate yields from N-propargyl- L-proline ester derivatives under mild conditions. Synthesis of indolizidine alkaloid from N-propargyl- L-pipecolinic esters using this strategy was also attempted.