Copper-catalyzed three-component spiroannulation: modular access to 1,3,7,8-tetraazaspiro[4.4]nona-3,6-dienes via a metal-free and subsequent Cu( ii ) relay strategy

A one-pot cyclization of β , γ -unsaturated hydrazones followed by Cu-catalyzed [3+2] cycloaddition with oximes and nitriles gives 1,3,7,8-tetraazaspiro[4.4]nona-3,6-dienes under air.