Inorganic ligand-supported Mo oxide as a hydrogen atom transfer photocatalyst for direct C(sp2)–H phosphorylation

Abstract

Visible-light-induced C(sp²)–H phosphorylation of 2H-thiozoles/quinoxalines with H-phosphine oxides was achieved using an inorganic-ligand supported Mo oxide ([N(C₄H₉)₄]₂[Mo₆O₁₉]) as a hydrogen atom transfer (HAT) photocatalyst. The developed photo-driven C(sp²)–P bond formation protocol could furnish a wide range of products with excellent functional group tolerance in a water-based solvent at room temperature, without the addition of metals, bases, additives or external oxidants. A gram-scale reaction can occur in a low catalyst loading system. Moreover, the formulated photocatalyst showed excellent stability and reusability, and also exhibited satisfactory photo-reactivity under sunlight irradiation. The mechanistic investigations supported that the C(sp²)–P bond formation went through radical coupling or radical nucleophilic addition pathways.