)imines derivedfrom enolizable carbonyl compounds have been investigated. Three different procedures were studied: (i) the aza-Claisen condensation of ethyl-[N-(diethoxyphosphoryl)]-formimidate with enolizable ketones, (ii) the reaction between diethyl N-sulfinylphosphoramidate and aliphatic aldehydes, and (iii) the thermally induced reaction of diethyl phosphoramidate with ketonediethyl acetals