Abstract: The overall goal of organic synthesis is to synthesize target molecules with cheap raw materials, the shortest and most reasonable synthetic route, and the highest yield. Amino functional groups exist in many physiologically active compounds. The protection strategy of amino groups is very important for the personnel conducting synthetic work, especially the selective protection of amine compounds. In this experiment, copper nanoparticles prepared by students are used to catalyze the selective protection of the amino group of 3-amino-1-propanol by (Boc)₂O to prepare N-Boc-3-amino-1-propanol in high yield, and without by-products. The experiment guides undergraduates to apply chemical selectivity to the design of green synthetic route. Compared with the traditional method of using Boc to protect amino groups, this experiment has so many advantages, such as recyclable catalyst, solvent free, stirred at room temperature, short reaction time, and high yield.