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
在TME
DA的存在下,
联苯与2.4摩尔
正丁基锂的
锂化反应可直接产生2,2'-二
硫代衍
生物(I),但可用于制备。反过来,我被转换为多种产品。通过单独的实验直接显示了2-
锂硫代
联苯的2'-位置的活化。MNDO计算表明,通过双桥联反应,I稳定;通过Li与邻苯基的分子内π相互作用,2-Lithiobiphenyl稳定。取代过渡态中的相似相互作用使观察到的反应的特异性合理化。