Efficient Syntheses of Indolizine‐3‐Phosphonates via Pyridinium Ylide 3+2 Reactions

ABSTRACT An efficient method for the synthesis of indolizine‐3‐phosphonates has been successfully developed via a 3+2 cycloaddition reaction of phosphonate‐containing pyridinium ylides with 1,1‐dimethylthioalkenes under mild conditions. The scope of this reaction and subsequent functional group transformations was systematically investigated, providing a variety of structurally diverse phosphonate‐containing indolizines in moderate to high yields. This new methodology significantly broadens the repertoire of tools to rapidly access heterocyclic phosphonates, which are often explored for their important biological activities.