Halogen Promoted Desulfurative Cleavage of Cyclopropylmethyl Thioethers and Amination of the Formed Cyclopropylcarbinyl Cations

Abstract

Cyclopropylmethyl sulfides react with N‐fluorosulfonimide (NFSI) or molecular iodine, enabling C–S cleavage to generate cyclopropylcarbinyl cations, which evolve through cyclopropane ring‐opening reactions into homoallyl cations suitable to react with nucleophiles present in the reaction media. This desulfurative cleavage of cyclopropylmethyl thioethers under non‐acidic conditions facilitates homoallylation of N‐based nucleophiles such as alkyl or aryl amines as well as sulfonimides through a one‐pot protocol in one or two steps depending on the nucleophile. The reaction is initiated by a halogen‐sulfur bond that causes C–S bond cleavage. Moreover, the reaction with iodine proceeds through homoallyl iodide intermediates.