Alkynes are important motifs in pharmaceuticals, materials, and synthetic chemistry. Herein, we report a redox-neutral deacylative coupling of ketone-derived dihydro-1,2,4-triazoles with alkynylsulfones. The transformation proceeds without light irradiation, stoichiometric oxidants or reductants, strong acids, or metal catalysts. Under mild conditions, a range of internal alkynes, including late-stage alkynylated derivatives of natural products and pharmaceuticals, are obtained in moderate to excellent yields. Mechanistic studies support a radical pathway involving aromatization-driven β-scission of ketone-derived dihydrotriazole intermediates to generate alkyl radicals, followed by α-addition to alkynylsulfones and β-elimination to afford the internal alkynes, with the resulting sulfonyl radicals closing the reaction cycle via SET or HAT.
