Directed Metalation of 1-Ester-Substituted Indolizines: Base/Electrophile-Controlled Regioselective Functionalization

A variety of C-2 and C-5 difunctionalized indolizines have been prepared through the reaction of 1-ester-substituted indolizines with organometallic bases followed by a reaction with different electrophiles. Metalation takes place under mild conditions allowing the isolation of a number of difunctionalized indolizines in good yields. The regioselectivity of the reaction appears to be governed by the nature of the base and electrophile.