- Cobalt(II)-Catalyzed [5+2] C?H Annulation of o-Arylanilines with Alkynes: An Expedient Route to Dibenzo-[b,d]azepines
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The first example of CoCl2-catalyzed formal [5+2] oxidative annulation of o-arylanilines with alkynes was developed, giving access to various important imine-containing dibenzo-[b,d]azepine scaffolds through sequential C?C/C?N bond formation. The reaction employs catalytic amount of manganese and oxygen as cooxidants, and features a broad substrate scope. Preliminary mechanistic studies suggested that C?H activation is involved in the rate-determining step. Moreover, both internal and terminal alkynes are well tolerated in this transformation. Besides, a regioselective migratory insertion was observed when using terminal alkynes as substrates. (Figure presented.).
- Ling, Fei,Xie, Zhen,Chen, Jiachen,Ai, Chongren,Shen, Haiwei,Wang, Ze,Yi, Xiao,Zhong, Weihui
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p. 3094 - 3101
(2019/05/21)
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- Metal-Oxidant-Free Cobalt-Catalyzed C(sp2)-H Carbonylation of ortho-Arylanilines: An Approach toward Free (NH)-Phenanthridinones
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A traceless directing group assisted Co-catalyzed C(sp2)-H carbonylation of ortho-arylanilines for the synthesis of free (NH)-phenanthridinones in metal-based-oxidant-free fashion was accomplished. This protocol employs diisopropyl azodicarboxylate as the CO source and oxygen as the sole oxidant, and provides good yields with various functional tolerance. The methodology has been applied for the total synthesis of PARP inhibitor PJ-34. Furthermore, the kinetic isotopic effect experiments reveal the C-H bond cleavage probably occurred in the rate-determining step.
- Ling, Fei,Zhang, Chaowei,Ai, Chongren,Lv, Yaping,Zhong, Weihui
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p. 5698 - 5706
(2018/05/23)
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- Synthesis of carbazoles by copper-catalyzed intramolecular C-H/N-H coupling
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A Cu-catalyzed intramolecular C-H amination for the synthesis of carbazoles has been developed. The key to success is the installation of the picolinamide-based directing group, which is spontaneously removed after the coupling event. The Cu catalysis proceeded smoothly under Pd- and I(III)-free conditions, and its mild oxidation aptitude enables the rapid and concise construction of heteroatom-incorporated carbazole core π-systems.
- Takamatsu, Kazutaka,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 2892 - 2895
(2014/06/23)
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