Bis(dimethylvinylene) pyrophosphate

BIS(DIMETHYLVINYLENE) PYROPHOSPHATE is a phosphorylating agent; selective for primary alcohols over secondary alcohols, especially in the presence of  triethylamine; used for the preparation of various unsymmetrical phosphodiesters; precursor of the more reactive  phosphorylating agents 4,5-dimethyl-2-chloro-2-oxo-1,3,2-dioxaphosphole and 4,5-dimethyl-2-(1′-imidazolyl)-2- oxo-1,3,2-dioxaphosphole.

BIS(DIMETHYLVINYLENE) PYROPHOSPHATE can be prepared from 4,5-dimethyl-2-methoxy-2-oxo-1,3,2-dioxaphosphole (1) by treatment with  pyridine in benzene to form the salt (2), followed by reaction with phosgene in benzene (eq 1). The solid (3) is recrystallized from CH2Cl2/hexanes.