Hindered α,β,γ,δ-dienones have been shown to react with aryl iodides in the presence of the [Pd(OAc) 2(PPh 3) 2]-trialkylammonium formate reagent to give mainly 1,4-conjugate addition type products. The α,β,γ,δ-dienones were prepared through reaction of the corresponding vinyl triflates with α,β-enones in the presence of Pd(OAc) 2, K 2CO 3, and tetrabutylammonium chloride at room temperature.