Unnatural amino acids are key structural motifs of peptidomimetics,peptides and many other pharmaceutically compounds[1].Generally,unnatural amino acids can be obtained by chemical and enzymatic resolutions of the racemates or through asymmetric synthesis.While considering the widespread availability of natural amino acids,an attractive approach from the viewpoint of atom economy would be to use them as substrates and perform direct C–H activation to access their unnatural counterparts[2].Therein an efficient protocol for Pd(II)-catalyzed directed arylation of amino acids derivatives by using 1,2,3-triazole as removable directing group has been developed.The protocol could be applied to synthesis some unnatural amino acids which cant be obtained by asymmetric hydrogenation in synthetically useful yields and possesses several attributes,including compatibility with a variety of functional groups.