Simons R Thomas, Nandakumar Meganathan, Kwon Kitae, Ayer Suraj K, Venneti Naresh M, Roizen Jennifer L
Department of Chemistry, Duke University, Box 90346, Durham, North Carolina 27708, United States.
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States.
J Am Chem Soc. 2023 Feb 13. doi: 10.1021/jacs.2c13409.
Site-selective functionalization of unactivated C(sp)-H centers is challenging because of the ubiquity and strength of alkyl C-H bonds. Herein, we disclose a position-selective C(sp)-C(sp) cross-coupling reaction. This process engages C(sp)-H bonds and aryl bromides, utilizing catalytic quantities of a photoredox-capable molecule and a nickel precatalyst. Using this technology, selective C-H functionalization arises owing to a 1,6-hydrogen atom transfer (HAT) process that is guided by a pendant alcohol-anchored sulfamate ester. These transformations proceed directly from N-H bonds, in contrast to previous directed, radical-mediated, C-H arylation processes, which have relied on prior oxidation of the reactive nitrogen center in reactions with nucleophilic arenes. Moreover, these conditions promote arylation at secondary centers in good yields with excellent selectivity.
由于烷基C-H键的普遍性和强度，未活化的C(sp)-H中心的位点选择性官能团化具有挑战性。在此，我们公开了一种位置选择性C(sp)-C(sp)交叉偶联反应。该过程涉及C(sp)-H键和芳基溴化物，利用催化量的具有光氧化还原能力的分子和镍预催化剂。使用该技术，由于由侧链醇锚定的氨基磺酸酯引导的1,6-氢原子转移（HAT）过程，实现了选择性C-H官能团化。与先前的定向、自由基介导的C-H芳基化过程相反，这些转化直接从N-H键开始，先前的这些过程在与亲核芳烃的反应中依赖于反应性氮中心的预先氧化。此外，这些条件能以良好的产率和优异的选择性促进仲中心的芳基化。
