We studied the influence of acetic acid concentration on the deamination and dephosphonylation of the adduct resulting of the nucleophilic reaction between adequate α-metalated phosphonate and imminium salt, to enhance the yield of such reactions in order to access efficiently a lot of unsymmetrical TTF derivatives. A mechanism is proposed for the formation of TTF, including steps, i 1 to i 7 . The potential concurrent formation of phosphonate 1 and other by-products is also discussed.