An unsymmetrical approach to the synthesis of bismethylene triphosphate analogues.

A protected, unsymmetrical bismethylene triphosphate analogue was prepared by sequential Michaelis-Arbuzov reactions on ethyl bis(halomethyl)phosphinates. This species was monodeprotected at one of the terminal phosphonate groups in high yield. The resulting monodeprotected compound was used to achieve the first syntheses of the bismethylene triphosphate analogues of UTP and CTP.