Aminochlorination of Alkenes with CFBSA

A novel catalyst-free aminochlorination of alkenes was developed by the direct addition of alkenes to N-chloro-N-fluorobenzenesulfonamide (CFBSA). The reaction produces 2-chloro-3-fluoramino and 3-chloro-2-fluoroamino adducts in 1,2-dichloroethane under reflux and dichloromethane at room temperature, respectively, in a regioselective manner. The electronic and steric effects of the fluorine atom of CFBSA have proven to be crucial for the reactivity and regioselectivity. A variety of transformations have been achieved to form 2-chloroenamines, chloroamines, aziridines and N-phenylbenzenesulfonamides under different conditions. Notably, the N-F bond in the adducts formed could be a useful handle for further transformations to useful compounds in organic synthesis.