Economical synthesis of tert-butyl (S)-3-aminopyrrolidine-1-carboxylate from L-aspartic acid

3-Aminopyrrolidine building block was used as the intermediate for many pharmaceutically active substances. Starting from L-aspartic acid, optically active (S)-tert-butyl-3-aminopyrrolidine-1-carboxylate was synthesized, and the reaction conditions were optimized in each step. The procedure of each step was discussed in detail and could be useful for the industrial preparation. This process was featured by readily available starting material, mild reaction conditions, easy work-up, and economy.