Background: The asymmetric Michael-Henry cascade reaction of 1,2-dione with nitroolefins
is an important method for the preparation of chiral bicycle[3,2,1] octane derivatives, which are useful
intermediates for the synthesis of biologically active bicyclo octane skeletal compounds. However, limited
success has been achieved so far for ionic liquid supported (ILS) chiral ligands in transition metal
catalyzed asymmetric cascade reactions.
Methods: The catalyst was generated in situ by the combination of ammonium ILS diamine 6b ligand
(3 mol%) with metal salt Ni(OAc)2 (3 mol%) in a solvent dimethylformamide. Then the substrates 1,2-
cyclohexadione and nitroolefin were added and the reaction mixture was stirred at room temperature for
Results: The ammonium ILS diamines were successfully utilized as chiral ligands in Ni(II)-catalyzed
asymmetric Michael-Henry cascade reactions between 1,2-cyclohexadione and nitroolefins at room
temperature. High yields (80-98%), high diastereoselectivities (up to 47:1) and enantioselectivities (84-
94% ee) were observed for the various bicyclo [3,2,1] octane derivatives containing many functional
Conclusion: 1,2-cyclohexadione underwent asymmetric Michael-Henry cascade reaction with nitroolefins
in the presence of ammonium ILS diamine/Ni(II) catalyst to give the bicyclo [3,2,1] octane derivatives
in high yields with ee ranging from 84-94%. Furthermore, the catalytic system is recyclable.