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

Abstract 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 Introduction 1.1 Organophosphorus Compounds 1.2 Phosphorylation: Construction of C–P(V) Bonds 1.3 Photochemistry as an Alternative to Classical Phosphorylations 2 Ionic Mechanisms Involving Nucleophilic Additions 3 Mechanisms Involving Radical Intermediates 3.1 Mechanisms Involving Reactive Carbon Radicals 3.2 Mechanisms Involving Phosphorus Radicals 3.2.1 Photoredox: Direct Creation of Phosphorus Radicals 3.2.2 Photoredox: Indirect Creation of Phosphorus Radicals 3.2.3 Dual Catalysis 3.3 Photolytic Cleavage 4 Conclusion and Outlook