Institute of Organic Chemistry, University of Münster , 48149 Münster, Germany.
J Am Chem Soc. 2014 Oct 8;136(40):13999-4002. doi: 10.1021/ja507940k. Epub 2014 Sep 29.
Helical chirality and selective anion-binding processes are key strategies used in nature to promote highly enantioselective chemical reactions. Although enormous efforts have been made to develop simple helical chiral systems and thus open new possibilities in asymmetric catalysis and synthesis, the efficient use of synthetic oligo- and polymeric helical chiral catalysts is still very challenging and rather unusual. In this work, structural unique chiral oligotriazoles have been developed as C-H bond-based anion-binding catalysts for the asymmetric dearomatization of N-heteroarenes. These rotational flexible catalysts adopt a reinforced chiral helical conformation upon binding to a chloride anion, allowing high levels of chirality transfer via a close chiral anion-pair complex with a preformed ionic substrate. This methodology offers a straightforward and potent entry to the synthesis of chiral (bioactive)heterocycles with added synthetic value from simple and abundant heteroarenes.
螺旋手性和选择性阴离子结合过程是自然界中用于促进高度对映选择性化学反应的关键策略。尽管已经做出了巨大的努力来开发简单的螺旋手性体系，从而为不对称催化和合成开辟新的可能性，但有效利用合成的低聚和聚合物螺旋手性催化剂仍然非常具有挑战性，而且相当不常见。在这项工作中，开发了结构独特的手性寡三唑作为基于 C-H 键的阴离子结合催化剂，用于 N-杂芳烃的不对称去芳构化。这些可旋转的柔性催化剂在与氯离子结合时采用增强的手性螺旋构象，允许通过与预形成的离子底物形成紧密的手性阴离子对配合物进行高水平的手性转移。该方法为从简单且丰富的杂芳烃中合成具有附加合成价值的手性（生物活性）杂环化合物提供了一种直接且有效的途径。
