ETUDE DE LA REACTION DE DIHYDROXYLATION DE PHOSPHONATES α,β-, β,γ- ET γ,δ-ETHYLENIQUES A L'AIDE D'HYDROPEROXYDES CATALYSEE PAR LE TETROXYDE D'OSMIUM: SPECIFICITE D'ACTION DE L'HYDROPEROXYDE DE TERTIOBUTYLE

Abstract

The catalytic cis dihydroxylation of alkenyl phosphonates using Osmium tetraoxide is reported. First, we confirm that the hydrogen peroxide-Osmium tetroxide system leads to the diol-ketol mixture. On the other hand, the use of the tert-butyl hydroperoxide-Osmium tetroxide system in presence of tetraethylammonium acetate overcomes the overoxidation reaction and good yields of threo dihydroxyalkyl phosphonates are obtained. The stereoselectivity of the reaction and the intramolecular cyclisation of these diols are briefly discussed.