Preparation method of tembotrione

The present invention relates to a tembotrione preparation method, which adopts a one-pot method to prepare tembotrione, and specifically comprises: adding an organic alkali, a reaction solvent, 2-chloro-3-(2, 2, 2-trifluoroethoxy) methyl-4-methylsulfonylbenzoic acid and a Carter condensing agent into a reaction container, and carrying out a heating reflux reaction for 3-5 h to generate an active ester intermediate; and after the reaction liquid containing the active ester intermediate is cooled, adding 1, 3-cyclohexanedione and acetone cyanohydrin, and carrying out condensation rearrangement reaction to generate tembotrione. According to the invention, a one-pot synthesis process is adopted, the use of dimethyl sulfoxide is avoided, and compared with the traditional process, the method has the advantages of greenness, environmental protection, low safety risk, high yield and good purity, and is more suitable for industrial production. 本发明涉及环磺酮的制备方法，采用一锅法制备环磺酮，具体包括如下步骤：将有机碱、反应溶剂、2-氯-3-(2,2,2-三氟乙氧基)甲基-4-甲磺酰基苯甲