1-(N-Acylamino)-1-triphenylphosphoniumalkylphosphonates: General synthesis and prospects for further synthetic applications

A general approach for the synthesis of 1-(N-acylamino)-1-triphenylphosphoniumalkylphosphonates from readily accessible alkyl imidate hydrochlorides has been developed. The three-step synthesis involves acylation of the imidate hydrochloride with an acyl chloride, the Michaelis–Becker-like addition of diethyl phosphite to the N–acylimidate and subsequent nucleophilic substitution of the ethoxy group of the 1–ethoxyphosphonate derivative with triphenylphosphonium tetrafluoroborate. 1–(N–Acylamino)-1-triphenylphosphoniumalkylphosphonates were demonstrated to be promising intermediates for further synthetic transformations toward α-functionalized derivatives of α–aminophosphonic acids and α,β-dehydro-α-aminophosphonates.