Direct Enantioselective α‐Allylation of Unfunctionalized Cyclic Ketones with Alkynes through Pd‐Amine Cooperative Catalysis

The first direct enantioselective α‐allylation of unfunctionalized cyclic ketones using alkynes as an economical choice of reagent is reported. This transformation uses a simple procedure with commercially available palladium, chiral bisphosphine ligand and chiral amine catalysts, and affords valuable ketones with a α‐tertiary stereocenter in good to high enantiopurity. In this transformation, a chiral palladium complex containing the ( S )‐DIFLUORPHOS ligand catalyzes the isomerization of alkynes into an electrophilic allylpalladium species, which is attacked by the enamine generated in situ from the condensation of ( R )‐prolinol with the ketone substrate.