Abstract Through the use of [PdCl (C 3 H 5)] 2/cis, cis, cis-1, 2, 3, 4-tetrakis ( diphenylphosphinomethyl) cyclopentane as a catalyst, a range of aryl bromides undergo Heck reaction with ethyleneglycol vinylether to give regioselectively protected arylacetaldehydes in good yields. The β-arylation products were obtained in the range 93- 98% selectivity with electron-poor aryl bromides. Furthermore, this catalyst can be used at ...