Direct Synthesis of Sulfonylated Spiro[indole-3,3′-pyrrolidines] by Silver-Mediated Sulfonylation of Acrylamides Coupled with Indole Dearomatization

A dearomative tandem spiro-cyclization reaction of N-[(1H-indol-3-yl)­methyl]­methacrylamide derivatives with sulfinate sodium in the presence of AgNO₃ and K₂CO₃ is reported, which produced sulfonylated spiro­[indole-3,3′-pyrrolidines] in medium to excellent yields. The characteristics of this transformation contain good functional group tolerance and ease of operation.