Asymmetric α-Pentadienylation of ß-Ketocarbonyls and Aldehydes by Synergistic Pd/Chiral Primary Amine Catalysis

Direct alkylation with skipped enynes or cyclopropropylacetylenes represents an ideal process for the installation of pentadienyl group in terms of atom- and step-economy. The development of catalytic asymmetric versions has been frequently pursued and most of the successes have been achieved with enolizable aldehydes. We herein describe a synergistic chiral primary amine/Pd catalysis for asymmetric a-pentadienylation of ss-ketocarbonyls and aldehydes with skipped enynes or cyclopropropylacetylenes. The reaction features the construction of acyclic all-carbon quaternary centers with high enantioselectivity, and good functional group tolerance and scalability.