ChemInform Abstract: Synthesis of 5-Fluoro- and 5-Bromoalkylisoxazoles via Nitrosation of 1,1-Dihalocyclopropanes with Sulfur Trioxide Activated Nitrosyl Chloride

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.