Synthesis of Monofluoroalkenes through Visible-Light-Promoted Defluorinative Alkylation of gem-Difluoroalkenes with 4-Alkyl-1,4-dihydropyridines

In this study, a facile and efficient method to synthesize monofluoroalkenes by photoredox catalytic defluorinative alkylation of gem-difluoroalkenes with 4-alkyl-1,4-dihydropyridines under mild conditions (room temperature) is described. This novel strategy is applicable for a broad range of gem-difluoroalkene substrates with good functional group tolerance and a variety of 4-alkyl-1,4-dihydropyridines (including primary, secondary, and even tertiary alkyl radicals). Moreover, it also allows the challenging radical coupling with glycosyl-based 4-alkyl-1,4-dihydropyridines (DHPs) to synthesize monofluoroalkenylated saccharides.