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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. [ABSTRACT FROM AUTHOR]

The first sequential acid-catalyzed propargylation/base-mediated aza -cycloisomerization between indolyl-benzimidazoles and propargylic alcohols is described. This protocol enables the one-pot construction of N -fused benzimidazo-β-carbolines in good yields. The synthetic utility of this approach is demonstrated by the assembly of an aza -helicene and also by a gram-scale reaction.