New approaches to β-trifluoromethylated enone derivatives

β-Trifluoromethylated enaminones 1 were prepared stereospecifically or high stercoselectively in 31–92% yields from the reaction of Weinreb amides with trifluoropropynyl lithium, followed by quenching with H2O in the presence of amine derivatives. β-Trifluoromethylated enaminone 1a was reacted with aryl or alkynyl Grignard reagents to give Michael addition products 5 at 0 °C, whereas addition–elimination adducts, β-aryl (or alkynyl)-β-trifluoromethylated enones 6, were obtained stereospecifically in 50–92% yields after stirring at room temperature for several hours.