Organic Letters 2003-03-20

Naphthalenes, isoquinolines, and a benzazocine from zirconocene-copper-mediated coupling of benzocyclobutadiene with nitriles and alkynes.

T V V Ramakrishna, Paul R Sharp

Index: Org. Lett. 5(6) , 877-9, (2003)

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Abstract

[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].