Vanadyl Acetylacetonate Catalyzed Methylenation of Imidazo[1,2‐ a ]pyridines by Using Dimethylacetamide as a Methylene Source: Direct Access to Bis(imidazo[1,2‐ a ]pyridin‐3‐yl)methanes

An efficient protocol has been developed for the methylenation of imidazo[1,2‐ a ]pyridines using dimethylacetamide (DMA) as methylene source in the presence of vanadyl acetylacetonate [VO(acac) 2 ] as the catalyst and iodobenzene diacetate as the oxidant. The reaction involves coupling of sp 3 ‐ and sp 2 ‐hybridized carbons and proceeds through the formation of an iminium ion. A wide variety of imidazo[1,2‐ a ]pyridines were converted to bis(imidazo[1,2‐ a ]pyridin‐3‐yl)methanes in good to excellent yields. A gram‐scale reaction demonstrated the potential for the scale‐up processes.