Synthesis of Sterically Hindered Biaryls by Zr‐Mediated Co‐cyclotrimerization of Alkynes

Abstract

Abstract Treatment of zirconacyclopentadienes with ortho ‐substituted arylpropynoates in the presence of stoichiometric amounts of CuCl or NiBr 2 (PPh 3 ) 2 represents a novel approach to the synthesis of biaryls, formed in good yields. The CuCl‐mediated reaction proceeded through two reaction mechanisms, also affording Dewar benzenes together with the corresponding biaryls. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)