Sulfonyl Ketenimines as Key Intermediates in One-Pot Synthesis ofN-Sulfonyl-2-alkaneimidoyl Selenocyanates

A synthesis of fuctionalized 2-amino-3-cyano pyrroles from terminal alkynes, sulfonyl azides and phenacylmalononitriles

A new strategy for the construction of functionalized 2-amino-3-cyano pyrroles has been developed. The reactions involved a copper-catalyzed azide-alkyne cycloaddtion reaction between terminal alkynes and sulfonyl azides followed by generation of N-sulfonoketenimine intermediates. Interception of these reactive ketenimines by phenacylmalononitriles in the presence of copper(I) iodide and Et₃N afforded the expected products. The reaction proceeded smoothly in THF at ambient temperature to afford the target compounds in 70-92% yields and excellent regioselectivity. Evidence for the structure of a typical product is obtained from single-crystal X-ray analyses.

Copper-catalyzed three-component cascade reaction of alkynes, sulfonyl azides and simple aldehydes/ketones

A copper-catalyzed dimethylzinc-promoted three-component cascade reaction of alkynes, sulfonyl azides, and simple aldehydes or ketones is described, which delivers polysubstituted olefins expeditiously in one pot under mild conditions.