Samarium Diiodide-Induced Asymmetric Synthesis of Optically Pure Unsymmetrical Vicinal Diamines by Reductive Cross-Coupling of Nitrones with N-tert-Butanesulfinyl Imines

[reaction: see text] An efficient method for the preparation of optically pure unsymmetrical vicinal diamines by the SmI(2)-induced reductive cross-coupling of nitrones with chiral N-tert-butanesulfinyl imines was developed. This is the first successful example of the highly diastereoselective and enantioselective cross-coupling between two different imine species. It provides a straightforward access to enantiopure unsymmetrical vicinal diamines that are widely applicable in asymmetric synthesis.