Shining Light on the Light-Bearing Element: A Brief Review of Photomediated C–H Phosphorylation Reactions

Organophosphorus compounds have numerous useful applications, from versatile ligands and nucleophiles in the case of trivalent organophosphorus species to therapeutics, agrochemicals and material additives for pentavalent species. Although phosphorus chemistry is a fairly mature field, the construction of C–P(V) bonds relies heavily on either prefunctionalized substrates such as alkyl or aryl halides, or requires previously oxidized bonds such as C=N or C=O, leading to potential sustainability issues when looking at the overall synthetic route. In light of the recent advances in photochemistry, using photons as a reagent can provide better alternatives for phosphorylations by unlocking radical mechanisms and providing interesting redox pathways. This review will showcase the different photomediated phosphorylation procedures available for converting C–H bonds into C–P(V) bonds.1 Introduction1.1 Organophosphorus Compounds1.2 Phosphorylation: Construction of C–P(V) Bonds1.3 Photochemistry as an Alternative to Classical Phosphorylations2 Ionic Mechanisms Involving Nucleophilic Additions3 Mechanisms Involving Radical Intermediates3.1 Mechanisms Involving Reactive Carbon Radicals3.2 Mechanisms Involving Phosphorus Radicals3.2.1 Photoredox: Direct Creation of Phosphorus Radicals3.2.2 Photoredox: Indirect Creation of Phosphorus Radicals3.2.3 Dual Catalysis3.3 Photolytic Cleavage4 Conclusion and Outlook