Synthesis of heteroaryl 1,2-diketones.

Reactions of lithiated heteroaryl- (or aryl-) methylbenzotriazoles 4a−e with heteroaryl (or aryl) esters 5a−f give α-benzotriazolyl ketones 6a−n in average yields of 90−95%. Oxidation of ketones 6a−l in aqueous DMSO in the presence of oxygen and sodium bicarbonate gave heteroaryl- (aryl-) 1,2-ethanediones 7a−l in average yields of 60−80%.