Phase Transfer of Enantiopure Werner Cations into Organic Solvents: An Overlooked Family of Chiral Hydrogen Bond Donors for Enantioselective Catalysis

Werner complexes go organic! When orange aqueous solutions of [Co(1,2-diamine)3]X3 (X=I, Cl) are treated with solutions of NaBArf in CH2Cl2 (1:3 mol ratio), the aqueous phases decolorize (see scheme) and [Co(1,2-diamine)3](BArf)3⋅nH2O can be isolated from the CH2Cl2 phases (78–89 %). The ethylenediamine complex can catalyze enantioselective Michael additions, presumably by an outer-coordination-sphere mechanism involving hydrogen bonding.