Geminal bis(sulfoximine)s: Synthesis and applications in asymmetric catalysis

A number of C-2-symmetrical geminal bis(sulfoximine)s have been prepared for the first time and used as ligands in boron-mediated reductions of acetophenone and copper complex-catalyzed 1,4-additions of diethylzinc to 2-cyclohexenone. The copper complex of bis(sulfoximine) 46 was found to be highly active in this type of reaction, furnishing the addition product in nearly quantitative yield even at - 90degreesC. From the reaction of bis(sulfoximine) 42 with Cu(OTf)(2) a copper complex was isolated and characterized by X-ray structural analysis. A mixture of SES-Cl and NaN3 in acetonitrile was found to behave like SES-N-3 in FeCl2-mediated iminations of sulfoxides, affording the corresponding sulfoximines with complete retention of the sulfur configuration.