Enantioselective Friedel-Crafts Alkylation of Indoles with β,γ-Unsaturated α-Ketoesters Catalyzed by New Copper(I) Catalysts.

New Cu(I) catalysts are effective in enantioselective Friedel-Crafts alkylation of a variety of indoles with different β,γ-unsaturated α-ketoesters. A control study shows that such a catalyst system is less sensitive to air, and the reactions can be carried out without special cares such as glovebox operation or moisture/oxygen-free conditions. Preliminary computation results suggest that there exists π-π stacking between the substrate and the catalyst, and such an interaction seems to play a role in stabilizing the reaction intermediate and enhancing the stereoselectivity of the reactions.

Enantioselective Michael addition of malonates to β,γ-unsaturated α-ketoesters catalysed by Cu(II) complexes bearing binaphthyl-proline hybrid ligands.

High yields (up to 96%) and high ee (up to 92%) were achieved for chiral copper(II) complex-catalysed enantioselective Michael addition of malonates to β,γ-unsaturated-α-ketoesters. The chiral ligands took advantage of both the binaphthyl and the proline moieties, and substituents with different electronic and steric features could be tolerated. The reactions could be carried out under mild conditions, and a gram scale reaction could be realised without the loss of yield and enantioselectivity.