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

Abstract

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.