Alcoholysis Versus Fission of the Ester Group During the Reaction of Dialkyl Phenylphosphonates in the Presence of Ionic Liquids

In the microwave-assisted alcoholysis of dialkyl phenylphosphonates performed in the presence of suitable ionic liquids, such as [bmim][BF₄] or [bmim][PF₆], affording the phosphonate with mixed alkoxy groups and the fully transesterified product, the fission of the phosphonate function to the ester-acid or diacid moiety was inevitable. Moreover, in the presence of [emim][HSO₄], the reaction could be performed to afford the phosphonic esteracid with a selectivity of 66% and the diacid with a selectivity of 97%. The ester-acids provided by the new protocol may be valuable intermediates.