A Two‐Step Sequence to Ethyl α‐Fluorocyclopropanecarboxylates Through MIRC Reaction of Ethyl Dichloroacetate and Highly Regioselective Fluorination. Issue 32 (24th September 2013)

• Record Type: Journal Article
• Authors: Zhang, Min; Gong, Yuefa; Wang, Weizhou
• Is Part Of: European journal of organic chemistry. Issue 32(2013)
• Page Start: 7372
• Page End: 7381
• Publication Date: 2013-09-24
• Subjects: Synthetic methods -- Fluorine -- Small‐ring systems -- Elimination -- Nucleophilic addition; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201300978
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: A two‐step sequence to ethyl α‐fluorocyclopropanecarboxylates has been developed. Ethyl α‐chlorocyclopropanecarboxylates were first obtained through a Michael‐initiated ring closure reaction of terminal electron‐deficient olefins with ethyl 2, 2‐dichloroacetate under mild basic conditions. Subsequent smooth conversion into the corresponding monofluorinated analogues in good yields was through a halogen exchange reaction with potassium bifluoride. Further investigation clearly demonstrated that potassium bifluoride in this reaction system played a dual role of base and nucleophilic reagent. This is the first successful example reported hitherto for producing ethyl α‐fluorocyclopropanecarboxylate directly through fluorination of its chlorinated analogue with alkali bifluoride. Abstract : A convenient two‐step method to prepare ethyl α‐fluorocyclopropanecarboxylates has been developed. Ethyl α‐chlorocycloproanecarboxylates were obtained through Michael‐initiated ring closure reactions under mild reaction conditions in good yields before being smoothly converted into the corresponding monofluorinated analogues through halogen exchange reactions with potassium bifluoride in good yields. The reaction mechanism was also investigated.