Abstract The selective Heck arylation of acrolein diethyl acetal catalysed by [Pd (NH 3) 4] Cl 2 in the presence of RAME-β-CD in water as solvent is described. Depending on the base (ie NaOAc or HN (i-Pr) 2) good to high selectivity's towards, respectively, the cinnamaldehydes 2 or the 3-arylpropionic esters 1 were achieved. The results support that depending on the base different palladium intermediate complexes are formed. Using ...