Palladium-Catalyzed Synthesis of 3-Acyl-2-aminobenzofurans via Three-Component Coupling Reactions

摘要

Transition metal-catalyzed addition reactions to nitriles have received considerable attention as poweful tool for the synthesis of amines and amides. We recently reported a novel palladium-catalyzed cycloisomerization of 2-(cyanomethyl)-phenyl esters 1 leading to the formation of 3-acyl-2-aminobenzofurans 2. The reaction involves oxidative cleavage of an acyl-oxygen bond of ester by a low-valent palladium complex and intramolecular oxypalladation of a cyano moiety (Scheme 1).