Rhodium-zentrierte Bildung eines Cyclobutenyl-Liganden und Umlagerung in einen Cyclopentadienyl-Komplex / Rhodium-centered Formation of a Cyclobutenyl Ligand and Rearrangement to a Cyclopentadienyl Complex

Abstract

Abstract Cyclization of two diphenylacetylene molecules occurs if [(cod)RhCl] 2 (cod = 1.5-cyclooc-tadiene) is treated with methyllithium in the presence of tolane. The isolated (cod)Rh complex 2 contains an exo-methyl-tetraphenylcyclobutenyl ligand and was characterized by X-ray diffraction analysis. Thermolysis of 2 in acetonitrile causes ring expansion of the methylcyclobutenyl unit with formation of the tretraphenylcyclopentadienyl complex 3 together with 3-methyl-tet-raphenylcyclobutene. Mechanistic aspects are discussed as well as spectroscopic data of the new compounds.