Synthesis of 5-fluoro- and 5-bromoalkylisoxazoles via nitrosation of 1,1-dihalocyclopropanes with sulfur trioxide activated nitrosyl chloride

• Nitrosation of gem-bromofluorocyclopropanes is studied.
• A nitrosyl chloride sulfur trioxide adduct is used as a reagent.
• 5-fluoro- and 5-bromoalkylisoxazoles were synthesized.
• Fluorinated cyclopropanes exhibited excellent chemoselectivity for 5-fluoroisoxazoles.

A method for the synthesis of 5-fluoro- and 5-bromoalkylisoxazoles via nitrosation of alkylated gem-dihalocyclopropanes with a nitrosyl chloride sulfur trioxide adduct has been developed. In the case of bromofluorocyclopropanes the reaction proceeded with excellent chemoselectivity thus providing exclusively 5-fluoroisoxazoles.

Figure optionsDownload as PowerPoint slideA method for the synthesis of 5-fluoro- and 5-bromoalkylisoxazoles via nitrosation of alkylated gem-dihalocyclopropanes with a nitrosyl chloride sulfur trioxide adduct has been developed. In the case of bromofluorocyclopropanes the reaction proceeded with excellent chemoselectivity thus providing exclusively 5-fluoroisoxazoles.