Photocatalytic 1,4-Phosphonocarboxylation of 1,3-Enynes with CO2: Synthesis of Tetrasubstituted Phosphorus-Containing Allenic Acids

Abstract Herein, we report a visible-light photoredox-catalyzed Phosphonocarboxylation of 1,3-enynes with diarylphosphine oxides and CO2, utilizing a cost-effective photosensitizer under transition-metal-free and base-free conditions. This reaction enables the highly regioselective synthesis of a diverse range of tetra-substituted allenoic acids bearing phosphoryl group. Characterized by broad substrate scope, excellent regio-/chemoselectivity and facile scalability, it provides a practical platform for the construction of functionalized allenes with great potential for further derivatization.