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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

No abstract

No abstract

No abstract

Organo-phosphorus compounds S 0080Phosphonyl Radical Addition to Enol Ethers. The Stereoselective Synthesis of Cyclic Ethers. -Diethylphosphite or diethylthiophosphite readily undergo addition reactions to enol ethers allowing a regioselective synthesis of organophosphonates or phosphonothioates. Dienic substrates such as (VIII) and (X) are diastereoselectively converted to cyclic ethers under these conditions. The latter products include the derivative (XIc) which can be transformed to the racemic core tetrahydropyran (XII) of tetronomycin. -(JESSOP, C. M.; PARSONS*, A. F.; ROUTLEDGE, A.; IRVINE, D. J.; Tetrahedron Lett. 45 (2004) 26, 5095-5098; Dep. Chem., Univ. York, Heslington, York YO10 5DD, UK; Eng.) -Mais 40-174