Reactive Pi-Complexes Of The Electron Rich Transition-Metal Complexes .11. Construction Of C4-Units From Alkynes In The Coordination Sphere Of Arene Iron Complexes

The highly reactive arene iron complex [(eta-4-toluene)(eta-6-toluene)iron] allows the formation of C4-units from alkynes below room temperature. By this route butadiene-, cyclobutadiene-, and ferracyclopentadiene(arene)iron complexes are accessible. Synthesis, structure and the properties of one example each are reported. Ferracyclopentadienes are potential intermediates for the catalytic cyclotrimerization of alkynes in the coordination sphere of arene iron complexes.