Photoinduced Cobalt-Catalyzed Enantioselective Decarboxylative Cross-Sulfonylimine Coupling

The direct conversion of readily available and stable carboxylic acids into enantiomerically enriched chiral molecules has long been a valuable target for chemists. The high oxidation potential of carboxylic acids and the highly reactive radical intermediates generated in situ render enantioselective control particularly challenging. This report describes a photoinduced cobalt-catalyzed enantioselective decarboxylative cross-sulfonylimine coupling reaction that offers a promising approach to achieving this difficult reactivity. A charge-transfer complex derived from arylacetic carboxylate and sulfonylimine induced radical decarboxylation and subsequent enantioselective radical coupling under visible light and in the presence of a cobalt catalyst, thereby constructing tetrasubstituted chiral carbon centers with high enantioselectivity (up to 96% ee). Mechanistic investigations indicate that the cobalt salt serves as both the catalyst precursor and catalytic base, which is crucial for activating carboxylic acids. Notably, an exogenous photoredox catalyst is not needed in the developed protocol.