A synthesis of 2-aminobenzoxazoles from the parent C-H compound is described. The procedure involves deprotonation at the 2-position of the benzoxazole and quenching the intermediate organolithium species with a halogen electrophile. The 2-halobenzoxazole is then treated in the same pot with an amine nucleophile to afford the desired product. The substrate scope and selectivity of the reaction are presented. The method is operationally simple and provides access to a variety of amine products bearing additional nucleophilic heteroatoms. (C) 2011 Elsevier Ltd. All rights reserved.
Catalyst- and Reagent-Free Electrochemical Azole C−H Amination
作者:Youai Qiu、Julia Struwe、Tjark H. Meyer、João C. A. Oliveira、Lutz Ackermann
DOI:10.1002/chem.201802832
日期:2018.9.3
Catalyst‐ and chemical oxidant‐free electrochemical azole C−H aminations were accomplished via cross‐dehydrogenative C−H/N−H functionalization. The catalyst‐free electrochemical C−H amination proved feasible on azoles with high levels of efficacy and selectivity, avoiding the use of stoichiometric oxidants under ambient conditions. Likewise, the C(sp3)−H nitrogenation proved viable under otherwise
Direct Copper-Catalyzed C-H Monofluoroalkylation of Benzoxazoles with 1-Fluoro-1-haloalkanes
作者:Wei Li、Andrii Varenikov、Mark Gandelman
DOI:10.1002/ejoc.201901929
日期:2020.6.8
Copper‐catalyzed cross‐coupling reaction allowed the first directC–Hmonofluoroalkylation of benzoxazole with 1‐fluoro‐1‐haloalkanes, which bear β‐hydrogens and no directing groups in vicinity to the reaction center.
Pd/Cu-Catalyzed C–H/C–H Cross Coupling of (Hetero)Arenes with Azoles through Arylsulfonium Intermediates
作者:Ze-Yu Tian、Zeng-Hui Lin、Cheng-Pan Zhang
DOI:10.1021/acs.orglett.1c01322
日期:2021.6.4
A highly efficient method for the selective formal C–H/C–H cross-coupling of azoles and (hetero)arenes was established through arylsulfonium intermediates under transition-metal catalysis, which produced a variety of 2-(hetero)aryl azoles in good to excellent yields. Advantages of the reaction included mildness, a good functional group tolerance, a wide range of substrates, a high regio- and chemoselectivity
Asymmetric Alkyl and Aryl/Azolation of Alkenes via a Single Cu(I) Complex
作者:Xiaodong Ma、Guozhu Zhang
DOI:10.1021/acscatal.0c05576
日期:2021.5.7
The copper-catalyzed, highly enantioselective alkyl and aryl/azolation of alkenes is reported. The employment of the chiral carbazole-based bisoxazoline (Cbzbox) ligand is critical to the success of this chemistry. Anionic tridentate ligands improve the reducibility of copper complexes, facilitating alkyl/aryl radical generation and providing good enantiocontrol in the azolation. The three-component
A catalytic asymmetric alkylation of azoles with secondary 1‐arylalkyl bromides through direct C−H functionalization is reported. Under blue‐light photoexcitation, a copper(I)/carbazole‐based bisoxazoline (CbzBox) catalytic system exhibits good reactivity and high stereoselectivity, thus offering an efficient strategy for the construction of chiral alkyl azoles. These reactions proceed at low temperature