Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea.
J Am Chem Soc. 2021 Feb 24;143(7):3003-3012. doi: 10.1021/jacs.1c00549. Epub 2021 Feb 8.
Site-selective C-H functionalization in chemical feedstocks is a challenging and useful reaction in the broad field of chemical research. Here, we report a modular photochemical platform for the site-selective C-H pyridylation of unactivated hydrocarbons via the unique synergistic effects of triplet excited anthraquinone and an amidyl radical-based reverse hydrogen atom transfer (RHAT) agent. The selective pyridylation of tertiary and secondary C(sp)-H bonds in abundant chemical feedstocks was achieved by employing various -aminopyridinium salts in a highly selective fashion, thus providing a new catalytic system for the direct construction of high-value-added compounds under ambient reaction conditions. Moreover, this operationally simple protocol is applicable to a variety of linear-, branched-, and cyclo-alkanes and more complex molecules with high degrees of site selectivity under visible-light conditions, which provides rapid and straightforward access to versatile synthons for upgrading feedstocks under mild, metal-free reaction conditions.
在化学研究的广阔领域中，化学原料的位点选择性 C-H 功能化是一项具有挑战性和实用性的反应。在这里，我们报告了一种模块化的光化学平台，用于通过三重态激发蒽醌和基于酰胺基自由基的反向氢原子转移 (RHAT) 试剂的独特协同作用，对未活化烃进行位点选择性 C-H 吡啶化。通过以高选择性的方式使用各种 -氨吡啶鎓盐，实现了丰富化学原料中叔 C(sp)-H 和仲 C(sp)-H 键的选择性吡啶化，从而为在环境反应条件下直接构建高附加值化合物提供了新的催化体系。此外，该操作简单的方案适用于多种直链、支链和环烷烃以及更复杂的分子，在可见光条件下具有高的位点选择性，为在温和、无金属反应条件下升级原料提供了快速而直接的途径，得到多功能的合成子。
