Tris(1,2-diphenylethylenediamine)cobalt(III) Complexes: Chiral Hydrogen Bond Donor Catalysts for Enantioselective α-Aminations of 1,3-Dicarbonyl Compounds

The enantiopure salt Delta-[Co((S,S)-dpen)(3)](3+)2Cl(-)B(C6F5)(4)(-) is an effective hydrogen bond donor catalyst for additions of 1,3-dicarbonyl compounds to di-tert-butyl azodicarboxylate in the presence of N-methylmotpholine (1.0:1.0:0.10) in CH3CN at 0 degrees C, as illustrated with educts derived from five- or six-membered ring ketones (99-88% yields, >99-91% ee) and cycloheptanone (94%, 72% ee) as well as 2-cyanoryclopentanone (92%, 45% ee) and an acyclic system (98%, >99% ee).