Diarylprolinol as a Ligand for Enantioselective Alkynylation of Cyclic Imines

An easily accessible prolinol derived ligand, (S)-bis(3,5-bis(trifluoromethyl)phenyl)(pyrrolidin-2-yl)methanol, has been efficiently applied in the catalytic enantioselective addition of terminal alkynes to cyclic imines using dimethylzinc (Me2Zn) under mild reaction conditions. The developed catalytic system led to chiral propargylic sulfamidates with high yields (up to 97%) and excellent enantioselectivities (up to 97% ee).