Synthesis of 3‑Sulfonylamino Quinolines from 1‑(2-Aminophenyl) Propargyl Alcohols through a Ag(I)-Catalyzed Hydroamination, (2 + 3) Cycloaddition, and an Unusual Strain-Driven Ring Expansion

We describe herein a silver-catalyzed
conversion of 1-(2-aminophenyl)-propargyl
alcohols to 4-substituted 3-tosylaminoquinolines using TsN3 as an amino surrogate. Controlled reactions reveal the pathway consisting
of Ag­(I)-catalyzed 5-exo-dig cyclization,
catalyst-free (2 + 3) cycloaddition, and ring-expansive rearrangement
via nitrogen expulsion. As a support study, we show that the cyclic
enamines in similar conditions produce amidines via a C–C bond
migration.