Dual Nickel/Photoredox-Catalyzed Arylsulfonylation of Allenes

• DOI: 10.1021/acs.orglett.4c01258
• Publication Date: 2024-06-10T17:43:06Z
• Authors: Yu Zhou; Wen-Hui Yang; Nan-Nan Dai; Jia-Yao Feng; Ming-Qi Yang; Wenqing Gao; Qiang Li; Chao Deng; Zhan Lu; Wen-Ting Wei

The nickel/photoredox dual catalysis system is an efficient conversion platform for the difunctionalization of unsaturated hydrocarbons. Herein, we disclose the first dual nickel/photoredox-catalyzed intramolecular 1,2-arylsulfonylation of allenes, which can accurately construct a C(sp2)-C(sp2) bond and a C(sp3)-S bond. The reaction exhibits excellent chemoselectivity and regioselectivity, allowing modular conformations of a diverse series of 3-sulfonylmethylbenzofuran derivatives. Control experiments showed that the bipyridine ligand is crucial for the formation of a stable σ-alkyl nickel intermediate, providing the possibility for sulfonyl radical insertion. Meanwhile, the electrophilic sulfonyl radical facilitates further oxidative addition of the σ-alkyl nickel intermediate and inhibits addition with allenes. In addition, control experiments, cyclic voltammetry tests, Stern-Volmer experiments, and density functional theory calculations afford evidence for the Ni(0)/Ni(I)/Ni(II)/Ni(III) pathway in this 1,2-arylsulfonylation.