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
Heterogeneously Porous γ-MnO<sub>2</sub>-Catalyzed Direct Oxidative Amination of Benzoxazole through CH Activation in the Presence of O<sub>2</sub>
作者:Provas Pal、Arnab Kanti Giri、Harshvardhan Singh、Subhash Chandra Ghosh、Asit Baran Panda
DOI:10.1002/asia.201402057
日期:2014.9
Oxidative amination of azoles through catalyticCHbond activation is a very important reaction due to the presence of 2‐aminoazoles in several biologically active compounds. However, most of the reported methods are performed under homogeneous reaction conditions using excess reagents and additives. Herein, we report the heterogeneous, porous γ‐MnO2‐catalyzed direct amination of benzoxazole with
Merging the ring opening of benzoxazoles with secondary amines and an iron-catalyzed oxidative cyclization towards the environmentally friendly synthesis of 2-aminobenzoxazoles
作者:Daqian Xu、Wenfang Wang、Chengxia Miao、Qiaohong Zhang、Chungu Xia、Wei Sun
DOI:10.1039/c3gc41206g
日期:——
A facile and environmentally friendly method was developed through merging the ring opening of benzoxazoles with secondary amines and an iron-catalyzed oxidative cyclization towards the synthesis of 2-aminobenzoxazoles. In the oxidative cyclization step, with catalytic amounts of FeCl and aqueous H2O2 as a green oxidant, highly desirable 2-aminobenzoxazoles were isolated in excellent yields of up to 97%. A plausible radical process is proposed for the oxidative cyclization on the basis of mechanistic studies.
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</sup>Bu<sub>4</sub>NI-catalyzed direct amination of benzoxazoles with tertiary amines using TBHP as oxidant under microwave irradiation
Abstract A facile, efficient, and practical method for nBu4NI-catalyzed direct C–H amination of benzoxazoles with tertiary amines has been developed. The system could be performed in the absence of metal catalyst and only requires tert-butyl hydroperoxide as oxidant under microwave irradiation. A variety of substituted benzoxazol-2-amines were synthesized with moderate to good yield.
In this article, a facile, efficient and practical method for Ni-catalyzed directC–H amination of benzoxazole with secondary amines has been developed. This procedure requires Ni(OAc)2·4H2O as catalyst, TBHP as oxidant and acid as the additive. A variety of substituted benzoxazol-2-amines were synthesized in moderate to good yields.