Development and application of a palladium-​catalyzed enantioselective conjugate addition

Abstract

The first enantioselective palladium-catalyzed, asym. construction of all-carbon quaternary stereocenters via 1, 4-addn. of arylboronic acids to cyclic, β-substituted enones is reported. A wide range of arylboronic acids and cyclic enones are reacted utilizing a catalyst prepd. from palladium(II) trifluoroacetate and a chiral pyridinooxazoline ligand to yield enantioenriched products bearing benzylic stereocenters. Recently, this methodol. has been expanded to support the reaction of heterocyclic chromone and 4-quinolone conjugate acceptors. Notably, this transformation is insensitive to air or moisture, providing a practical and operationally simple method of synthesizing enantioenriched stereocenters. The application of this reaction toward the total syntheses of members of the taiwaniaquinone sesquiterpenoid family of natural products is discussed