Organophotoredox-Catalyzed Carbamoylative Carboxylation of Alkenes at Ambient Pressure of CO2.

Owing to the inert nature and limited mass transfer of gaseous CO2 into the biphasic reaction medium, the direct incorporation of CO2 into complex molecular architectures at ambient temperature and pressure remains a daunting challenge. Here, the study reports a transition metal-free organophotoredox-catalyzed three-component difunctionalization of alkenes that integrates carbamoyl radicals with CO2 fixation under visible light irradiation via a reductive radical-polar crossover (RRPCO) mechanism. Remarkably, oxamic acids serve as bifunctional reagents, and the protocol operates under mild conditions, proceeds under direct sunlight irradiation, and is amenable to 13C labeling, late-stage modification of drugs, and succinimide and diamide scaffold synthesis. Mechanistic investigations and density functional theory calculations support the RRPCO pathway.