Reaction of Zirconocene−Carboryne Precursor with Alkynes: An Efficient Route to Zirconacyclopentenes Incorporating a Carboranyl Unit

Reaction of zirconocene−carboryne precursor Cp 2 Zr(μ-Cl)(μ-C 2 B 10 H 10 )Li(OEt 2 ) 2 with various kinds of alkynes R 1 C≡CR 2 in refluxing toluene gives the monoinsertion products 1,2-[Cp 2 ZrC(R 1 )═C(R 2 )]-1,2-C 2 B 10 H 10 in good to very high isolated yields with very good chemo- and regioselectivity. This reaction offers an efficient route to zirconacyclopentenes incorporating a carboranyl unit, a carborane version of zirconacyclopentadienes. All complexes have been fully characterized by various spectroscopic techniques and single-crystal X-ray analyses.