C–H Functionalization of Isoquinoline with Phosphites and Phosphine Chalcogenides

A simple and efficient method was developed for the synthesis of synthetically challenging 2-[(trifluoromethyl)sulfonyl]-1-phosphoryl-1,2-dihydroisoquinolines and 1-phosphorylisoquinolines, which involves preliminary activation of isoquinoline with trifluoromethanesulfonic anhydride, treatment of the corresponding triflate with phosphorus-containing compounds, and subsequent aromatization of the obtained σ H -adducts by elimination of the triflate moiety under basic conditions. The yields of 1,2-dihydroisoquinoline derivatives were up to 67%, and the yields of the aromatization step were up to 81%.