Palladium-Catalyzed Reaction of Aryl Bromides with 7-Hydroxy-1,3-Dienes

Palladium-catalyzed reaction of aryl bromides with 7-hydroxy-1,3-dienes proceeded in different reaction paths depending on the structure of the starting substrates. With cyclic 7-hydroxy-1,3-dienes, the reaction proceeded via insertion of the olefin into the Pd−O bond of a postulated Pd(Ar)(OR)-olefin complex to give a (η 1 -allyl)palladium intermediate, which underwent η 1 −η 3 −η 1 allylic rearrangement followed by C−C bond-forming reductive elimination to afford overall 1,4-alkoxyarylation products, while with acyclic 7-hydroxy-1,3-dienes, the reaction produced 1,2-alkoxyarylation products under the same reaction conditions. The 1,2-alkoxyarylation products resulted from insertion of the olefin into either the Pd−C or the Pd−O bond of the postulated Pd(Ar)(OR)-olefin complex followed by reductive elimination.