Electrochemical Multicomponent Cascade Radical Process Enabling Synthesis of Iodomethyl Spiropyrrolidinyl-Oxindoles

A novel electrochemical multicomponent cascade reaction of indole-tethered alkenes with CF3SO2Na and n-Bu4NI has been developed, which enables the rapid assembly of spiropyrrolidinyl-oxindoles in good yields. The experimental results and DFT calculations suggest that this reaction proceeds through the oxidation of CF3SO2Na, radical coupling with alkene, spirocyclization, oxidation of sulfinate, iodide substitution, and water coupling. This strategy features mild reaction conditions, easy-to-handle reactants, and good chemical yields. This finding not only enriches the research contents of indole-tethered alkenes but also provides a green strategy for the construction of spiropyrrolidinyl-oxindoles compared with the existing methodologies.