Department of Chemistry and Biochemistry, University of California, 5200 N. Lake Road, Merced, California 95343, United States.
J Org Chem. 2022 Jul 1;87(13):8492-8502. doi: 10.1021/acs.joc.2c00611. Epub 2022 Jun 16.
We report a new method for regioselective aromatic bromination using lactic acid derivatives as halogen bond acceptors with -bromosuccinimide (NBS). Several structural analogues of lactic acid affect the efficiency of aromatic brominations, presumably via Lewis acid/base halogen-bonding interactions. Rate comparisons of aromatic brominations demonstrate the reactivity enhancement available via catalytic additives capable of halogen bonding. Computational results demonstrate that Lewis basic additives interact with NBS to increase the electropositive character of bromine prior to electrophilic transfer. An optimized procedure using catalytic mandelic acid under aqueous conditions at room temperature was developed to promote aromatic bromination on a variety of arene substrates with complete regioselectivity.
我们报告了一种使用乳酸衍生物作为卤键受体与 - 溴代丁二酰亚胺（NBS）进行区域选择性芳基溴化的新方法。乳酸的几种结构类似物影响芳基溴化的效率，可能是通过路易斯酸碱卤键相互作用。芳基溴化的速率比较表明，通过能够形成卤素键的催化添加剂可提供反应性增强。计算结果表明，路易斯碱性添加剂与 NBS 相互作用，在亲电转移之前增加溴的正电性。在室温下的水相条件下，使用催化扁桃酸开发了一种优化的程序，以促进各种芳烃底物的芳基溴化，具有完全的区域选择性。
