New Indolizine Template from the Ugi Reaction

Abstract

Ugi reactions and [3+2] cycloaddition of pyridinium salts have been associated to provide an efficient multicomponent access to indolizines. The pyridinium salts are formed by an Ugi ­reaction using chloroacetic acid and propargylamine followed by pyridine addition on the Ugi adduct. The coupling of these salts with aryl iodides gives directly indolizine derivatives in a Sonogashira-cycloaddition-oxidation reaction cascade.