Why do silanes reduce electron-rich phosphine oxides faster than electron-poor phosphine oxides?

Abstract

Organophosphine-mediated reactions that generate PO-bonded byproducts can be transformed into catalytic processes by reducing the R₃PO byproduct back to PR₃in situ with a silane. DFT calculations explain why the most readily reduced phosphine oxides are those incorporating electron-rich (e.g. alkyl) substituents rather than electron-deficient (e.g. aryl) substituents.