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.

Access to Acyclic Z-Enediynes by Alkyne Trimerization: Cooperative Bimetallic Catalysis Using Air as the Oxidant.

Presented herein is a mild, operationally simple, mix-and-go procedure for the synthesis of acyclic trisubstituted Z-enediynes, from readily available terminal alkynes, in good yields. This method stems from a serendipitous discovery, and makes use of cooperative palladium/copper bimetallic catalysis and air as an oxidant to effect an intriguing alkyne trimerization to yield the valuable Z-enediyne moiety.