Catalytic Deoxygenative Coupling of Aromatic Esters with Organophosphorus Compounds.

We have developed a deoxygenative coupling of aromatic esters with diarylphosphine oxides/dialkyl phosphonates under palladium catalysis. In this reaction, aromatic esters can work as novel benzylation reagents to give the corresponding benzylic phosphorus compounds. The key of this reaction is the use of phenyl esters, an electron-rich diphosphine as a ligand, and sodium formate as a hydrogen source. Arylcarboxylic acids were also applicable in this reaction using (Boc)O as an additive. Palladium/dcype worked to activate the acyl C-O bond of the ester and to support the reduction with sodium formate.