Preparation process of (S)-nicotine

The invention discloses a preparation process for synthesizing (S)-nicotine, and belongs to the field of chemical synthesis. The novel (S)-nicotine synthesis method provided by the invention comprises the following steps: by taking 4-(3-pyridyl)-4-oxobutyraldehyde as an initial raw material and dichloro as a solvent, reacting with L-phenylalanine under the catalysis of acetic acid to generate a compound I; under the action of a Cu/ZnFe catalyst, hydrogen is introduced into the compound I by taking dichloromethane as a solvent, and the nicotine derivative is generated through hydrogenation; the method comprises the following steps: by taking palladium on carbon as a catalyst and dichloromethane as a solvent, carrying out hydrogenation reaction on a nicotine derivative, filtering palladium on carbon, adding formaldehyde, taking sodium borohydride as a reducing agent, reacting to generate nicotine, and purifying to obtain (S)-nicotine with the yield of 85.9% and the purity of 99.2%. 本发明公开了一种合成(S)-烟碱的制备工艺，属于化学合成领