Visible-Light-Mediated Tandem Difluoromethylation/Cyclization of Alkenyl Aldehydes toward CF₂H-Substituted Chroman-4-one Derivatives

Abstract

An efficient and facile visible-light-mediated tandem difluoromethylation/cyclization of alkenyl aldehydes, with easily accessible and air-stable [Ph₃PCF₂H]⁺Br^- as the difluoromethylation reagent, has been established. A range of CF₂H-substituted chroman-4-one skeletons and their derivatives, such as 2,3-dihydroquinolin-4(1<i>H</i>)-ones, chroman, 3,4-dihydronaphthalen-1(2<i>H</i>)-one, 2,3-dihydrobenzofuran, and 2,3-dihydro-1<i>H</i>-inden-1-one, are efficiently produced in moderate to good yields with excellent chemoselectivity under mild reaction conditions.