Dearomatized Alkylidene Dihydropyridines as Substrates for Mizoroki–Heck Cyclizations

Abstract

4-Substituted pyridines linked to iodoarene groups with alkyl amide tethers can be converted to the corresponding alkylidene dihydropyridines by treatment with ethyl chloroformate and Et3N. Subsequent exposure to Pd-catalyzed Mizoroki–Heck reaction conditions results in efficient intramolecular cyclization at the exocyclic alkene to afford isoindolinone and oxindole derivatives. Asymmetric construction of 3,3-disubstituted oxindoles and isoindolinones has also been achieved. This work demonstrates the ability to utilize reactive pyridine anhydrobases in metal-catalyzed transformations and provides the basis for design of new approaches to important heterocyclic ring systems.