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].
Ramakrishna
T V V
TV
Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
Sharp
Paul R
PR