Palladium-catalyzed heck reaction on 1-alkoxy-1,3-dienes:: A regioselective γ-arylation of α,β-unsaturated carbonyl compounds

[GRAPHICS] alpha,beta-Unsaturated acetals afford, in the presence of the LIC-KOR superbase, 1-alkoxybuta-1,3-dienes. These substrates cross couple with aryl derivatives in the presence of Pd catalyst (Heck conditions) in a regio- and stereoselective mode. With dialkyl acetals, the reaction affords arylated dienes; on the other hand, in the case of 1,3-dioxane derivatives, the final outcome of the process formally corresponds to the direct gamma-arylation reaction of the starting alpha,beta-unsaturated material.