Photocatalytic Reductive Azaarenylation of Cyclopropanes via Consecutive Photo-induced Electron Transfer: A Facile Route to α-Quaternary Azaarenes†

Abstract

α-Azaarene quaternary carbon centers are prevalent in drug molecules, making the development of efficient synthetic approaches of great interest. Herein, we describe an unprecedented method for constructing α-all-carbon quaternary carbon-centered azaarenes by employing photocatalytic reductive coupling of various 2,2-disubstituted cycloproarylketones with readily available cyanoazaarenes. The reaction proceeds with high efficiency, displaying excellent compatibility with various functional groups and demonstrating high chemo- and regioselectivity. Mechanistic investigations suggest that consecutive photo-induced electron transfer (ConPET) plays a crucial role in the formation of photocatalyst with greater reducing capability, ultimately enabling the direct reductive conversion of unreactive π-bonds under mild and transition-metal-free conditions.