Selective Synthesis of Polysubstituted Dihydroquinolines and α,β-Unsaturated Amidines by a Catalytic Reaction of Ynamides with Ketimines

Abstract

Ynamides reacted with benzophenone imines in the presence of triflic imide as a catalyst. Ynamides bearing a sulfonamide moiety gave the corresponding 2-amino-3,4-dihydroquinolines selectively in good to high yields. In contrast, yne-carbamates gave the corresponding α,β-unsaturated amidines exclusively. These methods permit simple preparation of sterically crowded polysubstituted quinolines and α,β-unsaturated amidines.