Naphthalenes, Isoquinolines, and a Benzazocine from Zirconocene−Copper-Mediated Coupling of Benzocyclobutadiene with Nitriles and Alkynes

[reaction: see text] Commercially available 1-bromobenzocyclobutene is a potentially useful synthon particularly with the application of organometallic methodology. Here we show that it is readily converted into Cp(2)Zr(benzocyclobutadiene), which couples with alkynes or nitriles giving five-membered zirconacycles. Treatment of these alkyne- or nitrile-derived zirconacycles with CuCl yields substituted naphthalenes, isoquinolines, or in the presence of MeO(2)C-CC-CO(2)Me, a 3-benzazocine containing an eight-membered ring [corrected].