Stereoselective approach for preparation of α-difluoromethyl α-propargylamines has been developed.1,2-Addition of lithium acetylides to diverse chiral difluoromethylated (S)-N-tert-butanesulfinyl ketimines by using Ti(oipr)4 as catalyst and THF as solvent afforded N-tert-butanesulfinarrfides in good to excellent yields (51-93％) and good diastereoselectivities (dr.85:15 to 93:7).The Ntert-butanesulfinyl group can be readily cleaved under mild acidic condition (4 mol/L HC1 in dioxane) to provide the corresponding α-difluoromethyl α-propargylamine in excellent yields (90-95％).