Reactions of Group 4 Metallocene Bis(trimethylsilyl)-acetylene Complexes with Nitriles and Isonitriles

This Review summarizes reactions of Group 4 metallocene bis(trimethylsilyl)acetylene complexes with nitriles and isonitriles. Selected examples of reactions of Group 4 metallocene alkyne complexes of the type Cp'M-2-(eta(2)-Me3SiC2SiMe3) with different nitriles and isonitriles are described following the general L-M-S principle, in which stoichiometric and catalytic reactions are influenced by ligands L, metals M, and substrate substituents S. The influence of all these parameters is highlighted. The basic reactions with nitriles and in some cases with isonitriles were investigated in detail and are summarized. Selected further reactions of the products again depend on L, M, and S. Most interesting feature for this is the formation of mono- and polynuclear 1-metalla-2,5-diazacyclopenta-2,4-dienes, which show great potential for the synthesis of complex heterocycles.