The 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 the aryl radical via the cleavage of the 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 a C2-radical iminium ion to undergo a cross-coupling reaction with an aryl radical, and this process offers an array of regioselective 2-aryl substituted 3-aminochromones.