Choppin S, Gros P, Fort Y
Synthèse Organique et Réactivité, UMR CNRS-UHP 7565, Faculté des Sciences, Université Henri Poincaré-NancyI, BP 239, 54506, Vandoeuvre-Les-Nancy, France.
Org Lett. 2000 Mar 23;2(6):803-805. doi: 10.1021/ol005538o.
The reaction of 2-chloropyridine with alkylithium generally results in nucleophilic addition leading to the loss of chlorine atom while exclusive directed ortho metalation is obtained using LDA. Herein it is shown that the BuLi-Me(2)N(CH(2))(2)OLi (BuLi-LiDMAE) superbase promotes an unprecedented regioselective C-6 lithiation. The method was successfully applied to the preparation of potentially useful chlorinated pyridinic and bis-heterocyclic synthons.
2-氯吡啶与烷基锂的反应通常会导致亲核加成，从而导致氯原子的损失，而使用LDA则可实现专一的邻位金属化。本文表明，丁基锂-二甲基氨基乙氧基锂（BuLi-LiDMAE）超强碱能促进前所未有的区域选择性C-6锂化反应。该方法已成功应用于制备潜在有用的氯化吡啶和双杂环合成子。
