Studies on Organophosphorus Compounds XXVI. New Aspects on the Synthetic Study of Some Cyclic Esters of Alkylphosphonic Acids

Various methods for the synthesis of some cyclic esters of alkylphosphonic acids, namely 2-alkyl-1,3,2-dioxaphosphorinane-2-oxides and phosphepane-2-oxides were investigated. A dilution method based on the concurrent addition of alkylphosphonyl dichloride and glycol in the presence of triethylamine gave satisfactory results. Cyclic phosphonic ester with exocyclic bulky substituent on phosphorus was prepared with better yield by alcoholysis of tert-butyl phosphonyl dichloride with disodium glycolate. Phase transfer catalytic P-alkylation of cyclic phosphites proceeded smoothly in most cases. The dependence of ring size and structure of the exocyclic alkyl group on the spectroscopic behaviors of these compounds was evaluated.