Photoredox-Catalyzed Phosphonocarboxylation of Allenes with Phosphine Oxides and CO₂

Abstract

Phosphonocarboxylation of allenes with diarylphosphine oxides and CO 2 via visible-light photoredox catalysis was developed for the first time. This work provided practical and sustainable access to highly valuable but otherwise difficult-toaccess linear allylic β-phosphonyl carboxylic acids in moderate yields with exclusive regio-and stereoselectivity. This method was also characterized by step and atom economy and transition-metal free and mild conditions. Preliminary mechanistic studies suggested that allyl-methyl carbanion species are the key intermediates.

Visible-light-promoted regioselective hydrocarboxylation of allenes with formate salt and CO2

“…11 In contrast, light-induced hydrocarboxylation of allenes has not been developed and remains a great challenge. As part of our ongoing interest in photocatalytic functionalization of unsaturated C–C bonds, 12 herein, we report the first example of visible-light-promoted hydrocarboxylation of allenes using commercially available [Ir(ppy) 2 (dtbbpy)]PF 6 as a photocatalyst, delivering β,γ-unsaturated linear carboxylic acids (Scheme 1c). It is worth noting that the selectivity of this reaction is complementary to previous transition-metal catalyzed methods.…”