ChemInform Abstract: Dinuclear Zinc Catalyzed Asymmetric Tandem Michael Addition/Acetalization Reactions of Cyclic Diketones and β,γ-Unsaturated α-Ketoesters.

The chiral complex generated in situ from diethylzinc and a bispyrrolidine ligand efficiently catalyzes the reaction of diketones (I) and (IV) with various α-ketoesters (II) to give chromene derivatives in high yields with an enantiomeric excess up to 96%. [ABSTRACT FROM AUTHOR]