Copper-Catalyzed Regioselective 1,4-Sulfonyl Indolylation of 1,3-Dienes with Sulfonyl Chloride and Indoles

A copper-based catalytic system has been described to enable the efficient 1,4-sulfonylindolylation of 1,3-dienes with sulfonyl chloride and indoles. This protocol offers a practical method for the synthesis of allylsulfone-containing indole derivatives with a broad range of compatible functionalities and excellent chemo- and regioselectivities. Mechanistic studies suggest that the copper catalyst plays the dual role of initiating sulfonyl radicals and prompting indole coupling in this conjugated diene-selective 1,4-difunctionalization strategy.