Novel Synthesis of Functionalized Indolizine Derivatives from Huisgen's Zwitterions and 1-Methylimidazole/Dichloroketene Adduct

The reactive zwitterionic intermediates, generated from addition of pyridine derivatives to dialkyl acetylenedicarboxylates, react with 1-methylimidazole/dichloroketene adduct to afford functionalized dialkyl 1-(2,2-dichloroacetyl)indolizine-2,3-dicarboxylates in moderate yields.