An expedient cleavage of the C-S bond of dimethyl sulfoxide (DMSO) has been developed for the preparation of substituted pyridines from ketones. In this transformation, the co-product formic acid was formed from ammonium formate, which acted as an important catalyst for the reaction. Notably, this transformation exhibited a broad substrate scope towards a wide variety of different ketones to give the corresponding substituted pyridines in high yields. Mechanistic studies suggested that dimethyl sulfoxide delivered a methylene fragment, which wa...