Synthesis of Alkylphosphonates via α, β -Unsaturated or α -Chloroalkylphosphonates from α -Hydroxyalkylphosphonates

Abstract

The chlorination of diethyl 1-hydroxyethylphosphonate, 1-hydroxybutylphosphonate, and α -hydroxybenzylphosphonate with thionyl chloride in the presence of pyridine gave the corresponding α -chloroalkylphosphonates in moderate yields. However, similar treatment of diethyl α -hydroxyphosphonates obtained from ketones and diethyl phosphite gave α, β -unsaturated phosphonates. Theses products were almost quantitatively converted into the saturated compounds by catalytic hydrogenation in ethanol using Raney nickel as catalyst. The results are given in the Table 1. This method seems to be useful for preparation of s-alkylphosphates which are di cult to obtain by the Mi6haelis-Arbuzov reaction and the Michaelis-Becker reaction.