1-acetoxyvinyl phosphonates: Facile synthesis via catalytic acylation of dialkyl phosphites

A new and facile method of synthesis of 1‐acetoxyvinyl phosphonates (2) has been found. Dialkyl phosphites react readily with acetic anhydride in acetonitrile solution in the presence of catalysts to produce 2 and acylphosphonates (1) as a minor product. The most efficient catalysts are metal compounds of variable valency: iron(II), iron(III), and cobalt(II) chlorides. The same compounds catalyze transformation of 1 into 2 in an acetonitrile solution of acetic anhydride.