condensation of functional phosphonates bearing strongly withdrawing groups (RO)2P(O)CH2Z1 with dimethylformamide dimethyl acetal gives corresponding β-functional, β-phosphonic enamines (RO)2P(O)C(Z)=CHNMe22. Acid or basic hydrolysis of the enamines frequently gives the free aldehyde (RO)2P(O)CH(Z)—CHO 3. We show that the enamines can be used with success for the synthesis of heterocycles like, pyrazoles