Electrochemical Domino Sulfonylation/Dearomative <i>ipso</i>‐Annulation of 2‐Alkynyl Biaryls to Access Spiro(indenyl)cyclohexadienones

Abstract Herein, we present an efficient strategy for the synthesis of spiro(indenyl)cyclohexadienones through radical‐promoted reaction of 2‐alkynyl biaryls with sodium sulfinates under electrochemical conditions. The reaction involves sulfonylation and dearomative ipso‐ cyclisation in a domino fashion. This approach features the use of readily accessible precursors, wide functional group tolerance and external oxidant‐free reaction conditions. The practicality of the method was also illustrated by scale‐up reaction and further diversification of the product.