Iminophosphoranes in heterocyclic chemistry. A simple one-pot synthesis of dihydropyrimidines and pyrimidines

The condensation of N-triphenylphosphoraniliden-benzamidine with acyclic α,β-unsaturated aldehydes produces dihydropyrimidines in good to high yields. The methodology has been extended to alicyclic and heterocyclic aldehydes.