Photocatalyst-free decarboxylative cross-coupling of α-keto acids with aryl sulfinates for the synthesis of S -aryl thioesters

We report a novel visible-light-induced, photocatalyst-free method for thioester synthesis from α-keto acids and sodium aryl sulfinates. Singlet oxygen mediates SET to form acyl radicals, while aryl sulfinates generate aryl thiosulfonates (RSO₂SR) via disproportionation. The radical-radical coupling of acyl and thiyl radicals enables efficient C-S bond formation under mild conditions. This photocatalyst-free protocol expands the synthetic utility of α-keto acids and aryl sulfinates and offers a valuable new entry into environmentally benign thioester synthesis.