Photoinduced α-addition and hydrogenation of carbazole-based alkenes

The conjugate addition of nucleophiles to electron-deficient alkenes is the fundamental reaction in organic synthesis. However, the regio-inversed α-addition reaction remains largely underexplored at current stage. Here, we report an unprecedented α-specific addition of N-heterocycles to carbazole-based electron-deficient alkenes under mild and photocatalyst-free conditions. Notably, the hydrogenation of alkenes can be achieved using thiophenol as both a hydrogen atom transfer (HAT) reagent and a hydrogen source. The broad functional group compatibility, excellent regioselectivity, successful late-stage functionalization of bioactive compounds, along with the scalable nature of the reaction, further highlight the synthetic value of this transformation. Herein, we report an unprecedented α-specific addition of N-heterocycles to carbazole-based electron-deficient alkenes under mild and photocatalyst-free conditions, enabling the efficient synthesis of a wide range of structurally diverse N-heterocycles in generally good yields.