Highly enantioselective addition of diethylzinc to diphenylphosphinoyl imines under dual amino Alcohol/Halosilane mediation

Arylethylene-derived, enantiomerically pure amino alcohols have been evaluated as ligands for the dual-catalyzed (amino alcohol/halosilane) enantioselective addition of diethylzinc to diphenylphosphinoyl imines. Among them, the conformationally restricted 9-fluorenone-derived ligand 4c provides the highest enantioselectivities so far reported over a range of substrate imines.