New efficient method for the stereoselective synthesis of alpha-(trifluoromethyl)-alpha,beta-unsaturated amides. Lewis acid-catalyzed reaction of 3,3,3-trifluoro-1-propynylamine with carbonyl compounds

N,N-Dibutyl-(3,3,3-trifluoro-1-propynyl)amine, prepared readily by the dehy drofluorination of N,N-dibutyl-(2,2,3,3,3-pentafluoropropyl)amine with lith ium diisopropylamide at room temperature, smoothly reacted with a variety o f aldehydes and ketones in the presence of a catalytic amount of Lewis acid and molecular sieves 4A at ambient temperature to give the corresponding a lpha-(trifluoromethyl)-alpha,beta-unsaturated amides in good to excellent y ields with high Z stereoselectivity.