REGIOSELECTIVE DIMETALLIERUNG VON AROMATEN. BEQUEMER ZUGANG ZU 2,2'-DISUBSTITUIERTEN BIPHENYLDERIVATEN

Article abstract of DOI:10.1016/S0022-328X(00)87089-8

Lithiation of biphenyl with 2.4 mol of n-butyllithium in the presence of TMEDA led directly to the 2,2'-dilithio derivative (I) in modest, but preparatively useful yields.I, in turn, was converted to a variety of products.The activation of the 2'-position of 2-lithiobiphenyl was shown directly by a separate experiment.MNDO calculations indicate stabilization in I by double bridging and in 2-lithiobiphenyl by intramolecular ? interaction of Li with the o-phenyl group.Similar interactions in substitution transition states rationalize the specificity of the reactions observed.