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.
Nat Commun. 2021 Sep 27;12(1):5657. doi: 10.1038/s41467-021-25696-z.
Remote functionalization of alkenes via chain walking has generally been limited to C(sp)-H bonds α and β to polar-functional units, while γ-C(sp)-H functionalization through controlled alkene transposition is a longstanding challenge. Herein, we describe NiH-catalyzed migratory formal hydroamination of alkenyl amides achieved via chelation-assisted control, whereby various amino groups are installed at the γ-position of aliphatic chains. By tuning olefin isomerization and migratory hydroamination through ligand and directing group optimization, γ-selective amination can be achieved via stabilization of a 6-membered nickellacycle by an 8-aminoquinoline directing group and subsequent interception by an aminating reagent. A range of amines can be installed at the γ-C(sp)-H bond of unactivated alkenes with varying alkyl chain lengths, enabling late-stage access to value-added γ-aminated products. Moreover, by employing picolinamide-coupled alkene substrates, this approach is further extended to δ-selective amination. The chain-walking mechanism and pathway selectivity are investigated by experimental and computational methods.
通过链行走对烯烃进行远程官能化通常仅限于 C(sp)-H 键 α 和 β 与极性官能单元,而通过受控烯烃易位实现的 γ-C(sp)-H 官能化则是一个长期存在的挑战。在此,我们描述了通过螯合辅助控制实现的 NiH 催化烯基酰胺的迁移形式氢胺化,其中各种氨基被安装在脂肪链的γ-位。通过通过配体和导向基团优化来调节烯烃异构化和迁移氢胺化,可以通过 8-氨基喹啉导向基团稳定 6 元镍环并随后由胺化试剂捕获来实现γ-选择性胺化。通过实验和计算方法研究了链行走机制和途径选择性。通过实验和计算方法研究了链行走机制和途径选择性。