N-Heterocyclic Carbene/Ni Synergistically Catalyzed Allylation of Aldehydes with Morita-Baylis-Hillman Carbonates.

N-Heterocyclic carbene (NHC)/transition metal (TM) synergistic catalysis has predominantly utilized palladium as the TM catalyst. We report an NHC/Ni synergistically catalyzed Tsuji-Trost-type allylation of simple aldehydes. Morita-Baylis-Hillman (MBH) carbonates serve as allyl sources, providing access to multi-substituted β,γ-unsaturated ketones. The reaction is completely regio- and stereoselective, proceeding solely via β-attack on MBH carbonates and affording the alkenes with E stereoselectivity. Furthermore, the mass study provides evidence that the NHC also serves as a ligand for Ni.