A Chiral Disulfoxide Ligand for the Efficient Rhodium-Catalyzed 1,2-Addition of Arylboroxines to N-Tosylarylimines

Enantiomerically pure diarylmethylamines are important building blocks in active pharmaceutical ingredients. Herein, we report a rhodium precatalyst with a chiral disulfoxide ligand that effects the 1,2-addition of arylboroxines to aromatic imines to give high yields and high enantioselectivities of these products. The present paper describes a system that is very simple, where the ease of synthesis of the chiral ligand is combined with low catalyst loadings and reaction conditions that do not need any additives or external base.