The Diels‐Alder reaction of 1‐aminovinylphosphonate esters has been studied for the first time as a suitable procedure leading to quaternary carbocyclic α‐aminophosphonates. The reaction is influenced by steric effects at the phosphonate functionality (bulky groups hinder the reaction) and electronic effects at the amino group (electron‐withdrawing substituents increase the reaction rate). The exo/endo ratio is constant, and no influence of the solvent is observed. The experimental results have been rationalized by DFT methods.

A versatile procedure for the synthesis of dehydrophos derivatives along with the effects of structural variations on bioactivity is reported.

Within this work an efficient procedure for the synthesis of the vinyl phosphonate tripeptide dehydrophos is described. This procedure constitutes a significant improvement over previously described strategies, since critical transformations in the synthesis of dehydrophos were carried out in only two synthetic steps, with higher yields and under smooth conditions. Thus, the dehydrophosphoalanine residue was generated by means of the Horner–Wadsworth–Emmons reaction of formaldehyde with a peptide bearing an aminomethylbis(phosphonate) moiety, whereas deprotection of the N‐terminal position of the thus‐obtained dehydrophosphonopeptide and partial hydrolysis of the dimethyl phosphonate residue took place simultaneously. In addition, we confirmed that the chiral integrity of the leucine residue was preserved throughout these transformations.