Base-induced regioselective radical arylation of 3-aminochromone with aryl hydrazine

A simple and efficient direct radical C-2 arylation of 3-aminochromone derivatives with aryl hydrazine is described. The aryl hydrazine acts as an initiator and source for aryl radical via cleavage of CN bond of aryl hydrazine. The reaction proceeds via a base promoted single electron transfer (SET) pathway. The aryl radical abstracts a single electron from 3-aminochromone, which generates C2-radical iminium ion to undergo cross-coupling reaction with aryl radical, and offers an array of regioselective 2-aryl substituted 3-aminochromones.