Acetylene-Triggered Reductive Incorporation of Phosphine Chalcogenides into a Quinoline Scaffold: Toward S_N^HAr Reaction

Abstract

Quinolines react with acylacetylenes and secondary phosphine chalcogenides at 20-75 °C to afford N-acylvinyl-2(1)-chalcogenophosphoryldihydroquinolines in good and excellent yields. Unlike the pyridine-derived similar intermediates, which eliminate E-alkenes to give aromatic chalcogenophosphorylpyridines, thereby completing S_N^HAr reaction, with quinolines, the reaction stops at the formation of the above phosphorylated N-acylvinyl-dihydroquinolines, thus representing a pendant S_N^HAr process. This reaction opens a one-pot atom-economic single-step access to pharmaceutically targeted phosphorylated functionalized dihydroquinolines and isoquinolines.