Regioselective Heck arylation of alpha-substituted allylic alcohols by aryl bromides was achieved by Pd-DPPP catalysis in ionic liquids, affording a beta/gamma ratio of up to 78/22 in the case of the coupling of 1-bromonaphthalene with but-1-en-3-ol. In addition to the effects of both ligands and reaction media, the regiocontrol toward the formation of branched products was significantly affected by the steric properties of allylic alcohols; with the increasing bulkiness of the substituent on allylic alcohol, the beta/gamma regioselectivity decreased. For comparison, arylation by aryl triflates in a molecular solvent was also demonstrated, which showed the same trend in regioselectivity. (c) 2007 Elsevier B.V. All rights reserved.