Study of the three-component reactions of 2 alkynylbenzaldehydes, aniline and dialkyl phosphites - the significance of the catalyst system

New, practical approaches for the synthesis of α-amino (2-alkynylphenyl)-methylphosphonates and 1,2-dihydroisoquinolin-1-ylphosphonates were developed. By the propylphosphonic anhydride (T3P®)-mediated Kabachnik-Fields reaction of 2 alkynylbenzaldehydes, aniline and dialkyl phosphites, α-amino (2-alkynylphenyl)-methylphosphonates were obtained selectively in high yields. The method developed is a simple operation and did not require a chromatographic sep-aration, since the products could be isolated from the reaction mixture by a simple extraction. At the same time, 2,3-disubstituted-1,2-dihydroisoquinolin-1-ylphosphonates could be prepared effectively from the same kinds of starting materials (2-alkynylbenzaldehydes, aniline and dialkyl phosphites) at 60 °C in a short reaction time by changing the catalyst for CuCl. Therefore, it was proved that the catalyst system applied played a crucial role in respect of the reaction outcome