Organocatalytic enantioselective conjugate addition to alkynones.
The first catalytic enantioselective addition of beta-dicarbonyl compounds to alkynones is presented. The conjugate addition proceeds in very high yields, giving a mixture of (Z)- and (E)-enones with up to 95% ee using the cinchona alkaloid [DHQ]2PHAL (5 mol %) as the catalyst. This organocatalytic enantioselective reaction has been further developed to a one-pot procedure to give the optically active (E)-enone adduct using first [DHQ]2PHAL (5 mol %), followed by Bu3P (10 mol %), as the catalysts.
Bella
Marco
M
Danish National Research Foundation: Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
Jørgensen
Karl Anker
KA