TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The drying agent is anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, or 4A molecular sieves. The reducing agent comprises lithium aluminum tetrahydride, potassium borohydride, lithium borohydride, sodium borohydride, or mixture of sodium borohydride and lithium chloride. The reduction promoter comprises lithium chloride, calcium chloride, aluminum trichloride, sodium cyanoborohydride, or sodium triacetoxyborohydride. The aqueous acidic solution includes hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, citric acid, nitric acid, acetic acid, or 1-6C-organic acid.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The esterification reaction comprises either dissolving ( plus minus )-2-azabicyclo(2.2.1)hept-5-en-3-one in methanol or ethanol at -10 degrees C to 10 degrees C, adding 1 equivalent of thionyl chloride to the obtained solution and then mixing until the reaction is completed, adding 0.6 equivalent of L-tartaric acid and 3 equivalents of water to the solution to adjust pH to 1.5-2.5, vacuum filtering the solution to obtain a filtrate, washing the filtrate with methanol or ethanol and then drying to obtain optically pure (1S,4R)-(-)-4-amino-cyclopent-2-enyl-methyl-L-tartaric acid, and adding 0.9 equivalent of D-tartaric acid to the filtrate to adjust the pH to 1.5-2.5, vacuum filtering the obtain solution to obtain a solid product, washing the solid product with ethanol or methanol and then drying to obtain optically pure (1R,4S)-(+)-4-amino-cyclopent-2-enyl-methyl-D-tartaric acid, or dissolving ( plus minus )-2-azabicyclo(2.2.1)hept-5-en-3-one in methanol or ethanol at -10 degrees C to 10 degrees C, adding 1 equivalent of thionyl chloride to the obtained solution and then mixing until the reaction is completed, adding 0.6 equivalent of D-tartaric and 3 equivalents of water to the solution to adjust pH to 1.5-2.5, vacuum filtering the solution to obtain a filtrate, washing the filtrate with methanol or ethanol and then drying to obtain optically pure (1R,4S)-(+)-4-amino-cyclopent-2-enyl-methyl-D-tartaric acid, and adding 0.9 equivalent of L-tartaric acid to the filtrate to adjust the pH to 1.5-2.5, vacuum filtering the obtain solution to obtain a solid product, washing the solid product with ethanol or methanol and then drying to obtain optically pure (1S,4R)-(-)-4-amino-cyclopent-2-enyl-methyl-L-tartaric acid. The amino protecting reaction comprises immersing (1S,4R)-(-)-4-amino-cyclopent-2-enyl-methyl-L-tartaric acid or (1R,4S)-(+)-4-amino-cyclopent-2-enyl-methyl-D-tartaric acid in ethyl acetate and then mixing, adjusting pH of the obtained solution to 7-8, adding 1 equivalent of di-tert-butyl dicarbonate to the solution, until reaction is completed, diluting the reacted solution with water, drying organic phase of the solution using a drying agent under reduced pressure and then distilling to obtain a residue, crystallizing the residue using a crystallization solvent to obtain optically pure (1S,4R)-4-amino-cyclopent-2-enyl-methyl ester or (1R,4S)-4-amino-cyclopent-2-enyl-methyl ester. The ester reduction reaction comprises dissolving (1S,4R)-4-amino-cyclopent-2-enyl-methyl ester or (1R,4S)-4-amino-cyclopent-2-enyl-methyl ester in a solvent to obtain ester solution, adding 1-5 equivalents of a reducing agent and 0.01-0.1 equivalents of reduction promoter to the ester solution and then mixing until the reaction is completed, quenching the solution with an aqueous acidic solution, drying the solution under reduced pressure, adding ethyl acetate and water to the solution and then stirring to separate organic phase of the solution, drying the organic phase of the solution using the drying agent under reduced pressure to obtain a residue, distilling the residue and then crystallizing using the crystallization solvent to obtain optically pure (1S,4R)-4-amino-cyclopent-2-enyl-methanol or (1R,4S)-4-amino-cyclopent-2-enyl-methanol. The preparation step is carried out at -10 degrees C to -80 degrees C. The removing step comprises dissolving (1S,4R)-4-amino-cyclopent-2-enyl-methanol or (1R,4S)-4-amino-cyclopent-2-enyl-methanol in 1-6C-alcohols, adding 1-5 equivalents of concentrated hydrochloric acid having a concentration of 37% and then stirring until the reaction is completed, drying the solution under reduced pressure to remove the solvent and volatiles and to obtain a residue, and crystallizing the residue and then drying.Preferred Components: The crystallization solvent comprises methylene chloride, ethyl acetate, methanol, ethanol, isopropanol, petroleum ether, n-hexane, n-heptane or toluene. The reduction reaction solvent includes tetrahydrofuran, or 1-6C-alcohols, preferably methanol, ethanol, propanol or isopropanol.