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.