Conversion of Cyclic Phosphorothioates into Halophosphates and Neutral Phosphorus Esters and Amides

Cyclic phosphorus esters and amides in the 1,3,2-dioxaphosphorinane-2-one series are usually obtained by the condensation of a diol with a suitable phosphorus oxyhalide. In the case of dissymetric diols the formation of two diastereoisomeric products, epimeric at phosphorus, can be expected. This procedure failed or proceeded with low yields when applied to the preparation of cyclic phosphates which would lead to the formation of sterically strained dioxaphosphorinane ring.1