Copper-Catalyzed Rearrangement of (Z)-Propynal Hydrazones via N-N Bond Cleavage

Propynal hydrazones are successfully converted to the corresponding 3-aminoacrylonitriles in the presence of copper catalysts in good to high yields. As an example, (Z)-N-(hex-2-ynylidene)morpholin-4-amine reacted in the presence of 10 mol % Cu(OAc)(2) in acetonitrile at 25 degrees C to afford (E)-3-morpholinohex-2-enenitrile ((E)-2 h) in 77% yield via C-N bond formation and subsequent beta-elimination involving cleavage of N-N and C-H bonds.