Light-Mediated Binaphthyl Enhanced [2 + 2] Dearomatization of Heterocycles via an Energy-Transfer Process.

Three-dimensional heterocycles are crucial in medicinal chemistry, yet efficient methods for their preparation remain limited. We report a light-mediated [2 + 2] dearomatization strategy for simple and benzo-fused heteroaromatics via energy-transfer activation. A binaphthyl cocatalyst combined with an Ir-photocatalyst enables high yields and selectivity under mild conditions. Mechanistic studies reveal the fundamental role of the cocatalyst in stabilizing reactive intermediates via dispersion interactions. The versatility of the products was demonstrated through synthetic applications that smoothly increased the molecular complexity.