text: The main area of application is the synthesis of synthetically challenging organic structures such as macrocycles and heterometallacycles. Rosenthal's reagent allows the selective preparation of these compounds with high yields.
  Currently, Rosenthals reagent is often used instead of Negishis reagent (1-butene)zirconocene to generate zirconocene fragments as it offers a number of compelling advantages. Unlike Negishis reagent, Rosenthals reagent is stable at room temperature and can be stored indefinitely under an inert atmosphere. A much more precise control over the stoichiometry of reactions is possible, especially because the instable (1-butene)zirconocene cannot be formed quantitatively. Stoichiometric and catalytic reactions can be performed and influenced by the use of different ligands, metals and substrate substituents. While for titanium complexes, a dissociative reaction mechanism has been observed, zirconium complexes favor an associative pathway. The combination of these organometallic complexes with different suitable substrates (e.g. carbonyl compounds, acetylenes, imines, azoles, etc.) often leads to novel bond types and reactivities. A particularly interesting aspect is the novel C–C coupling reaction of nitriles to form precursors for the realization of so far unknown heterometallacycles. As main side products of coupling reactions with Rosenthal's reagent, pyridine and bis(trimethylsilyl)acetylene are obtained. These compounds are soluble and volatile, and therefore easy to remove from the product mixture.