Catalytic versus stoichiometric coupling of alkynes with trimethylvinylsilane mediated by zirconocene

Trimethylvinylsilane and disubstituted alkynes underwent coupling reactions in the presence of the lanthanide-originated zirconocene equivalent. Both reactions, stoichiometric and catalytic in zirconium, could be carried out; in the latter case the addition of a stoichiometric amount of AlCl3 was needed. The catalytic cycle involving bimetallic polarization and a transmetallation step has been proposed.