Photoredox/HAT-Catalyzed\nIntramolecular Hydrocyclization\nof Alkenes toward 2,3-Fused Quinazolinones and Dihydroquinazolinones

New photochemical approaches to 2,3-fused quinazolinones\nand dihydroquinazolinones\nare disclosed. The intramolecular hydrocyclization proceeds in moderate\nto excellent yields across diverse alkenes with high regioselectivity\nand diastereocontrol. Mechanistic studies indicated that the radical\ncascade processes involve thiophenol acting as single-electron transfer\nand hydrogen atom transfer reagents. The success of the gram-scale\nsynthesis proves the strategy can be used for practical applications.