Direct Catalytic Enantioselective Vinylogous Aldol Reaction of Allyl Ketones to Pyrazole-4,5-diones.

The first catalytic enantioselective vinylogous nucleophilic addition to pyrazole-4,5-diones is reported. Using quinine-derived bifunctional tertiary amino-amide as the catalyst, this direct aldol reaction of allyl ketones is shown to proceed exclusively in γ- and E-selective manner to generate pyrazolone derivatives, bearing an oxygen-containing quaternary stereogenic center, in good yields with moderate to high enantioselectivities (up to 97:3 er).