Blue-light-triggered C[sbnd]C bond formation for synthesis of functional malononitrile using CBr4 as photocatalyst

Abstract

Compounds with cyclic structures derived from malononitrile are crucial in the field of pharmaceutics. Herein, we developed a facile synthetic protocol to give functional malononitrile derivatives via light-triggered alkylation using CBr4 as a photocatalyst under mild and eco-friendly conditions. A rich array of ethylene malononitriles, together with tetrahydrofuran were used as substrates, and metal-free coupling reaction occurred by forming new CC bonds. This reaction showed a wide range of scopes with tolerance of various functional groups with reasonable yields. Mechanism studies with the assistance of DFT calculations indicated such a reaction undertaking a radical pathway. We expected this protocol to be a useful platform for metal-free CC coupling reactions.