Metal-free synthesis of N-vinyl sulfoximines via DABCO-participated Michael addition of terminal carbonyl alkynes with N-chlorosulfoximines

A new method has been developed to prepare N-vinyl sulfoximines via a DABCO-participated Michael addition of carbonyl alkynes with N-chlorosulfoximines in the absence of metal. Various N-chlorosulfoximines and carbonyl alkynes were used as substrates in this novel protocol successfully, and only the corresponding (E)-N-vinyl sulfoximines were afforded in moderate yields. The establishment of this new synthetic method that featured good compatibility with air and high efficiency as well as the avoidance of transition metal would provide an alterative access to functional N-vinyl sulfoximines under green and simple conditions.