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.