Visible-Light-Induced Tandem Radical Addition-Cyclization of Alkenyl Aldehydes Leading to Indanones and Related Compounds.

Herein we describe a novel, visible light-induced tandem radical addition-cyclization of alkenyl aldehydes with α-bromocarbonyl compounds. A set of cyclic ketones, including indanones, cyclopentenones, 3,4-dihydronaphthalen-1(2H)-ones, and chroman-4-ones, are synthesized at room temperature with high efficiency and good functional group compatibility. It represents the first report on the catalytic 1,2-acylalkylation of unactivated alkenes.