Base-promoted cascade haloamination/β-elimination of alkenyl thianthrenium salts: access to ( Z )-β-chloroenamines

(Z)-β-Halo-enamines are widely found in natural products and drugs and are used in organic synthesis. However, accessing these molecules requires nucleophilic hydroaminations of 1-haloalkynes with amines. Herein, we report a catalyst-free, oxidant-free, base-promoted cascade chloramination/β-elimination of alkenyl thianthrenium salts with N-chlorosulfonamides, yielding (Z)-β-chloro-enamine products via π-π interactions. This reaction features mild reaction conditions, good functional group compatibility, excellent stereoselectivity, and high atom economy.