Catalytic Conjugate Addition of Allyl Groups to Styryl-Activated Enones

Conjugate addition of pinacolato(allyl)boron to benzylidenealkylidene ketones is remarkably facile when catalyzed by Ni(0) and Pd(0) complexes. Simple enones are inert to the reaction conditions, suggesting a significant activating effect by the auxiliary benzylidene unit. A comparison of different catalysts and substrates is provided, as is a mechanistic rationale, and an example of asymmetric catalysis.