BODIPY-Photocatalyzed Formal [5 + 1] Annulation of o -Alkenyl Aryl Sulfinylamines with CO2 toward Quinolines

Herein, we report a BODIPY photocatalyzed formal [5 + 1] annulation of o-alkenyl aryl sulfinylamines with CO2 for the synthesis of substituted quinolines. Unlike conventional CO2 incorporation reactions that retain the carbon dioxide-derived unit as carboxyl functionality, this transformation enables CO2 to serve as a ring-forming C1 synthon through a radical carboxylation, reduction, cyclization cascade. A range of o-alkenyl aryl sulfinylamines bearing various functional groups including carboxylic acid, ester, ether, alkyne, and heterocyclic moieties were well tolerated under the CO2 reaction conditions. Furthermore, this protocol is amenable to gram-scale synthesis and enables subsequent product diversification.