subjected to site-selective electrophilic substitution. The remote C2′-position is attacked by the superbasic mixture of n-butyllithium and potassium tert-butoxide (LICKOR, 3.5 equiv.) in THF or benzene at 20–60 °C. The resulting dianion cyclizes to give the fluorenone skeleton. The metalation reactions of biphenyl-3- and -4-carboxylic acids are also described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
未保护的
联苯-2-
羧酸可以在与
羧酸盐相邻的位置用
仲丁基锂完全
金属化,然后可以进行位点选择性亲电取代。在 20–60 °C 的 THF 或苯中,
正丁基锂和
叔丁醇钾(LICKOR,3.5 当量)的超碱性混合物会攻击远程 C2' 位。所得二价阴离子环化得到
芴酮骨架。还描述了
联苯-3-和-4-
羧酸的
金属化反应。(© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)