Regioselective Alkylacylation of 1,3-Dienes by Merging -Heterocyclic Carbene Catalysis with Photoinduced Palladium Catalysis.

Herein, we develop a dual catalytic platform for the 1,2- or 1,4-alkylacylation reaction of 1,3-dienes with readily available alkyl halides and aldehydes by merging -heterocyclic carbene catalysis with photoinduced palladium catalysis. A series of β,γ-unsaturated ketones are obtained in good to high yields. Mechanistic studies suggest that this reaction involves a radical process. The direct synthesis of flavanone from salicylaldehyde exemplified the potential capability of this dual catalytic platform.