Visible-Light-Promoted Cascade Radical Cyclization: Synthesis of Chroman-4-ones and Dihydroquinolin-4-ones.

A novel visible-light photoredox catalysis protocol for the effective and efficient synthesis of 3-substituted chroman-4-ones and 2,3-dihydroquinolin-4(1H)-ones via tandem radical addition/cyclization of alkenyl aldehydes has been described. This reaction features a broad substrate scope, mild reaction conditions, and good functional group tolerance character.