Rhodium-Catalyzed Asymmetric Arylation of <i>N</i>-(<i>tert</i>-Butanesulfinyl)imines with Sodium Tetraarylborates

A diastereoselective rhodium-catalyzed arylation of <i>N-</i>(<i>tert</i>-butanesulfinyl)­imines with sodium tetraarylborates is described. This method is general for constructing various chiral α-branched amines and 2-substituted pyrrolidines with high diastereoselectivity. A practical asymmetric approach to access chiral amines has been developed involving the use of air-stable Rh catalysts and reagents and in the absence of an external ligand.