5,6-Dihydroindolizines as Convenient Precursors of Indolizidine 167B and Analogues

Abstract

Starting from 5-carboxyethyl-5,6-dihydroindolizine, the title alkaloid was obtained in 25% overall yield via differently C5-substituted 5,6-dihydroindolizines and final exhaustive hydrogenation. An alternative strategy for the synthesis of optically active indolizidine 167B and analogues still based on 5,6-dihydroindolizine intermediates is given.

Synthesis of 3‐Butadienyl‐1‐tosylpyrroles

“…From that moment on, the synthesis and the reactivity of pyrroles with alkenyl substituents at the pyrrole ring carbon and nitrogen atoms have been the subject of our research for many years . These substrates have been shown useful starting material for naturally occurring molecules some of which, that is, (−)‐Myrmicarin 217 and Indolizidine 167B, biologically active .…”