Formation of new phosphates from aldehydes by a DBU-catalysed phospha-Brook rearrangement in a polar solvent

Addition of dialkylphosphites to aromatic aldehydes (Pudovik reaction) by treatment with a base results in two different possible reaction pathways depending on the solvent used. Apolar solvents give the normal Pudovik adduct, whereas the use of DBU in a polar solvent allows the formation of a phosphate ester via phospha-Brook rearrangement of the intermediate hydroxyphosphonate.