A Stereospecific Synthesis of Dialkyl(Aryl)-2-Nitroeth-1-Enylphosphonates and their Reactions with Non-Carbon Nucleophiles

Abstract

Dialkyl l-alkyl(aryl)-2-nitroen-l-enylphosphonates (1) are the important intermediate for the synthesis of functionalized phosphonic acids owing to the presence of reactive alkene and nitrogroups. It was expected that nucleophilic addition and subsequent reduction would result 2-aminólkyl phosphonic acid derivatives. On the other hand, conversion of nitrogroup into silylnitronate as reactive 1,3-dipole provides new synthetic route to phosphoryl isoxazoles. Compounds 1 were prepared by treatment of dialkyl 1 -alkyl(aryl) -1 -hydroxy-2-nitrólkylphosphonates with thionyl chloride and pyridine. The dehydration process underwent stereospecifically providing exclusive E-ismers. An E2 reaction mechanism is suggested.