The Synthesis of<i>N,N</i>-Bis(dialkoxyphosphinoylmethyl)- and<i>N,N</i>-Bis(diphenylphosphinoylmethyl)glycine Esters by the Microwave-Assisted Double Kabachnik-Fields Reaction
The condensation of a glycine ester, two equivalents of paraformaldehyde, and the same quantity of a dialkyl phosphite or diphenylphosphine oxide afforded the title compounds as new bis(phospha-Mannich) products under microwave (MW) conditions at 100 degrees C. The dialkoxyphosphinoylmethyl derivatives were synthesized under solvent-free conditions, whereas the diphenylphosphinoylmethyl derivatives