Oxy-sulfonylation of terminal alkynes via C–S coupling enabled by copper photoredox catalysis

Abstract

We report the first literature example using visible light-induced trimethylsilyl azide (TMS-N₃)-assisted copper-catalyzed oxy-sulfonylation of terminal CC bonds to form β-keto sulfones (C–S bond formation). TMS-N₃ promotes the reaction by facilitating the formation of sulfonyl radicals, which later decompose into N₂ gas upon light irradiation. This method involves the use of commercially available and stable starting materials. Also, a wide range of functional groups have been well-tolerated under the current photoredox process, evading the side product formation. Potent biologically active compounds, such as CES1, 11β-HSD1 inhibitors, anti-analgesic agents, and reactive synthesis intermediates were synthesized to demonstrate the synthetic utility of the current methodology. Moreover, green chemistry metrics and Eco-scale evaluation for the current photochemical method show that the protocol is eco-friendly and highly efficient.