Stereoselective Synthesis of Functionalized 1,3-Enynes through Recyclable Copper(I)-Catalyzed Three-Component Reaction of Terminal Alkynes, Diazoesters and Aldehydes

A highly efficient heterogeneous copper(I)-catalyzed three-component coupling of terminal alkynes, diazoesters and aldehydes has been achieved by using 10 mol% of copper(I) iodide complex [N,N-CuI-MCM-41] anchored on 2-aminoethylamino-modified mesoporous material MCM-41 as the catalyst under mild conditions, delivering a wide variety of 2-alkoxycarbonyl-substituted (E)-1,3-enynes in mostly good to high yields with excellent stereoselectivity. The heterogenized copper(I) complex can be facilely prepared from inexpensive reagents by using a simple procedure and exhibits a remarkably higher catalytic activity than CuI, and can be recycled more than ten times without a significant drop in its catalytic efficiency. This protocol represents the first example of heterogeneous copper-catalyzed stereoselective construction of functionalized 1,3-enynes from simple and commercially available starting materials.