Facile and Short Synthesis of (±) 1-Hydroxy Indolizidine and (±) Coniceine from Picolinic Acid Ethyl Ester via Cross Claisen Condensation

摘要

New short synthesis of (±) 1-hydroxy indolizidine (4) and (±) coniceine (5) are described starting from picolinic acid ethyl ester (6). The key steps are the conversion of the picolinic acid ethyl ester into β-keto ester 7 via cross Claisen condensation and hydrogenation of the β-keto ester in to hydroxy bicyclic amide (8) using PtO2/H2.