A Convenient Preparation of 3,3,3-Trifluoro-1-propynylamines and Their Lewis Acid Catalyzed Reaction with Carbonyl Compounds Leading to (Z)-α-(Trifluoromethyl)-α,β-unsaturated Amides¹

N,N-Dialkyl(3,3,3-trifluoro-1-propynyl)amines were readily prepared by a three-step procedure starting from commercially available 2,2,3,3,3-pentafluoropropanol. These fluorinated alkynylamines reacted smoothly with a variety of aldehydes or ketones in the presence of a catalytic amount of Lewis acid and molecular sieves 4Å at ambient temperature to produce the corresponding α-(trifluoromethyl)-α,β-unsaturated amides in good to excellent yields with high Z-stereoselectivity.