Direct photolysis of N-methoxypyridiniums for the pyridylation of carbon/heteroatom-hydrogen bonds

Current synthetic methods for the functionalization of pyridinium salts usually rely on transition metals,oxidants and/or photocatalysts.To date,no direct photolysis method exists under photocatalyst-,transition metal-and oxidant-free conditions.We herein demonstrate the first direct photolysis of N-methoxypyridinium salts for the selective assembly of various pyridines by using a series of common feedstocks,including amine-boranes,unactivated alkanes,phosphine oxides,amides,silanes and aldehydes.