Copper-Catalyzed Intermolecular Carbosulfonylation of Alkynes to Access Functionalized Eight-Membered Tetrahydroazocines

A copper-catalyzed tandem sulfonylation-cyclization of 3- aza -1,7-enynes with sulfonyl chlorides was developed for the efficient synthesis of sulfonylated eight-membered tetrahydroazocines in good yields and with excellent functional group compatibility. The regio - and chemoselective addition of sulfonyl radicals onto the alkynes of the tertiary enamide moiety triggers a cascade reaction followed by 8- endo cyclization, resulting in the generation of tetrahydroazocine derivatives. This transformation demonstrated a novel and efficient pathway to form eight-membered azocines, accompanied by the incorporation of a useful sulfone group.