Visible-light-induced copper-catalyzed regiodivergent C(sp3)-sulfonylation of oxime esters with sodium sulfinates

Abstract

Herein, we report a visible-light-induced copper-catalyzed regiodivergent sulfonylation of oxime esters with sodium sulfinates under mild conditions. The aliphatic C(sp³)–H bond in α-aryl-α-alkyl oxime esters reacted via a 1,3-hydrogen atom transfer (HAT) process and afforded β-ketosulfones. Meanwhile, γ,δ-unsaturated oxime esters afforded sulfonyl-functionalized pyrroline via an intramolecular olefin aminosulfonylation and 5-exo-trig cyclization procedure. Notably, this redox-neutral regiovergent alkyl-SO₂R coupling reaction features mild conditions, free from external reducing and oxidizing agents, low catalyst loading, broad substrate compatibility, and good functional group tolerance. Also, the reaction can be scaled up and trifluorobenzoic acid can be recovered. Mechanistic studies combined with computational analysis provide insights into the mechanism and the origin of the substituent-controlled regioselectivity.