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Thevanadium-catalyzed oxidative coupling of substituted 2-arylimidiazo[1,2-a]pyridines to N-methylmorpholine oxide,which acts as both a coupling partner and an oxidant, has been achieved.This reaction was applied to various substituted imidiazo[1,2-a]pyridine and indole substrates, resulting in yields ashigh as 90%. Mechanistic investigations indicate that the reactionmay proceed via a Mannich-type process. This work demonstrates howoxidative aminomethylation can be used as a useful method to introducetertiary amines into heterocycles, thus providing an alternative methodfor conventional Mannich-type reactions. [ABSTRACT FROM AUTHOR]