The Expedient and Regioselective Metalation of Unprotected Biphenyl??2??,??3??, and??4??carboxylic Acids

D Tilly, SS Samanta, AS Castanet…

Index: Tilly, David; Samanta, Subhendu S.; Castanet, Anne-Sophie; De, Asish; Mortier, Jacques European Journal of Organic Chemistry, 2006 , # 1 p. 174 - 182

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Citation Number: 17

Abstract

Abstract Unprotected biphenyl-2-carboxylic acid can be cleanly metalated with sec- butyllithium at the position adjacent to the carboxylate and can then be 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 ...