Navigating Visible-Light-Triggered (aza and thia) Paterno-Buchi Reactions for the Synthesis of Heterocycles

Harnessing visible light to trigger (aza and thia) Paterno-Buchi reaction injects new vitality into [2+2] photocyclization reaction and enable impressive reactivity modes. The popular (aza and thia) Paterno-Buchi reaction is one of the most efficient ways to synthesize strained four-membered heterocycles. Recently, visible-light-triggered (aza and thia) Paterno-Buchi reactions have received considerable attentions as this strategy has overcome some long-standing challenges, and remarkable achievements have been made within this field. Strained four-membered heterocyclics with favorable properties provide a perfect combination of stable skeletons for pharmaceutical chemistry and reaction intermediates for further transformation. In this review, we highlight the most recent advances in visible-light-triggered (aza and thia) Paterno-Buchi reaction with an emphasis on reaction mechanism and applications. Organization of the review follows a subdivision according to reaction type and substrate classes.