Organophotoredox-Catalyzed Carbamoylative Carboxylation of Alkenes at Ambient Pressure of CO ₂

Owing to the inert nature and limited mass transfer of gaseous CO 2 into the biphasic reaction medium, the direct incorporation of CO 2 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 CO 2 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 13 C labeling, late-stage modification of drugs, and succinimide and diamide scaffold synthesis. Mechanistic investigations and density functional theory calculations support the RRPCO pathway.