The Expedient and Regioselective Metalation of Unprotected Biphenyl-2-, -3-, and -4-carboxylic Acids
作者:David Tilly、Subhendu S. Samanta、Anne-Sophie Castanet、Asish De、Jacques Mortier
DOI:10.1002/ejoc.200500469
日期:2006.1
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)