Radical thioesterification via nickel-catalysed sensitized electron transfer

Multi-catalytic reaction modes have attracted widespread attention in synthetic chemistry. The merger of nickel catalysis with photoredox catalysis has offered a powerful platform for synthesis of molecules with attractive properties. Nonetheless, the conceptual development of nickel-catalysed, sensitized electron transfer is of pivotal relevance, but is still greatly limited. Here we describe the development of a radical cross-thioesterification process by nickel-catalysed sensitized electron transfer. The strategy can produce diverse methyl thioesters, which are not only found in natural products, materials and pharmaceuticals but also are widespread precursors in synthetic chemistry and biological processes. This catalytic mode features high chemoselectivity, good functional group tolerance and excellent scalability. Perhaps more important was the finding that various drugs and amino acids were successfully functionalized in this system. Experimental studies, nanosecond transient spectroscopic analysis, and density functional theory calculations reveal that the merger of photocatalytic electron transfer, energy transfer and nickel catalysis plays an essential role in this radical thioesterification reaction. The combination of nickel-catalysis and sensitized electron transfer is underdeveloped. Now, a nickel-catalysed sensitized electron transfer method for the synthesis of methyl thioesters from carboxylic acids is reported. Mechanistic investigations reveal that the merger of photocatalytic electron transfer, energy transfer and nickel catalysis plays an essential role in this thioesterification reaction.