Catalyst-free photochemical reactions of alkyl dihydropyridines via modulation of chromophores and light wavelength

This study describes an environmentally friendly strategy for thiolation and trifluoromethylthiolation of Hantzsch esters. The alkyl radical could be generated smoothly without any photocatalyst via modification of chromophores of alkyl dihydropyridines and wavelength of light. Besides, a broad alkyl dihydropyridine substrate scope and high functional group tolerance are observed. In addition, the modulation of chromophores and wavelength is applicable for other functionalizations such as halogenations and alkynylations of alkyl dihydropyridines.