Method for synthesizing 2-fluorocyclopropane carboxylic acid

Abstract

Disclosed is a new method for synthesizing 2-fluorocyclopropanecarboxylic acid comprising: 1) performing reaction of 1,1-dichloro-1-fluoroethane with thiophenol in the presence of an alkali, to produce a phenyl sulfide intermediate; 2) performing oxidation reaction of the phenyl sulfide intermediate with Oxone; 3) performing elimination reaction of the product of Step 2) in the presence of an alkali, to obtain 1-fluoro-1-benzenesulfonyl ethylene; 4) performing addition reaction of the 1-fluoro-benzenesulfonyl ethylene with ethyl diazoacetate in the presence of a catalyst, to obtain a cyclopropane intermediate; 5) performing elimination reaction of the cyclopropane intermediate in the presence of an alkali before acidification, to obtain 2-fluorocyclopropanecarboxylic acid. Herein, the synthetic route is short, used materials are bulk commodities, and raw materials are inexpensive and readily available. The process can be safely scaled up by replacing commonly used mCPBA reagents with Oxone. Further, reaction yield is improved, production cost is greatly reduced, and operation is simplified.

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