Radical addition reactions of phosphorus hydrides: Tuning the reactivity of phosphorus hydrides, the use of microwaves and Horner-Wadsworth-Emmons-type reactions

The reactivity of phosphorus hydrides in radical addition reactions are compared, and the substituents on phosphorus are shown to affect the efficiency of the reactions. The change in reactivity is attributed to the different bond dissociation energies of the P-H bonds, which have been calculated. Phosphorus hydrides with particularly weak P-H bonds are shown to undergo radical additions by microwave irradiation, in the absence of conventional initiators. These radical addition reactions produce phosphonothioates, phosphinothioates and phosphane sulfides, which react in HWE-type reactions, to afford substituted alkenes. (c) Wiley-VCH Verlag GmbH & Co.