Electrochemical Cyanomethylation/Halocyclization Reaction of p-QMs: Synthesis of Spirocyclohexane-1,2′-indene-2,5-dien-4-one Derivatives

An efficient synthesis of spirocyclohexane-1,2'-indene-2,5-dien-4-one derivatives has been accomplished by the reactions of para-quinone methides with haloacetonitrile under electrochemical conditions. In this synthesis, tandem radical additions resulted in a spiro skeleton by establishing a five-numbered ring, which features advantages such as a wide range of substrates, simple operation, good group tolerance, and only (Z)-configuration product. This work achieved the cyanomethylation and halogenation of para-quinone methides under electrochemical conditions to assemble multiple different functional groups.