Department of Chemistry, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
J Am Chem Soc. 2014 Oct 15;136(41):14389-92. doi: 10.1021/ja508469u. Epub 2014 Oct 3.
Transformations that selectively functionalize aliphatic C-H bonds hold significant promise to streamline complex molecule synthesis. Despite the potential for site-selective C-H functionalization, few intermolecular processes of preparative value exist. Herein, we report an approach to unactivated, aliphatic C-H bromination using readily available N-bromoamide reagents and visible light. These halogenations proceed in useful chemical yields, with substrate as the limiting reagent. The site selectivities of these radical-mediated C-H functionalizations are comparable (or superior) to the most selective intermolecular C-H functionalizations known. With the broad utility of alkyl bromides as synthetic intermediates, this convenient approach will find general use in chemical synthesis.
选择性官能化脂肪族 C-H 键的转化在简化复杂分子合成方面具有重要意义。尽管 C-H 官能化具有潜在的选择性，但很少有具有制备价值的分子间过程存在。在此，我们报告了一种使用易得的 N-溴代酰胺试剂和可见光进行未活化的脂肪族 C-H 溴化的方法。这些卤化反应以有用的化学收率进行，以底物为限制试剂。这些自由基介导的 C-H 官能化的位点选择性与已知的最选择性的分子间 C-H 官能化相当（或更优）。由于烷基溴化物作为合成中间体的广泛用途，这种方便的方法将在化学合成中得到广泛应用。
