- Versatile Cp*Co(III)(LX) Catalyst System for Selective Intramolecular C-H Amidation Reactions
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Herein, we report the development of a tailored cobalt catalyst system of Cp*Co(III)(LX) toward intramolecular C-H nitrene insertion of azidoformates to afford cyclic carbamates. The cobalt complexes were easy to prepare and bench-stable, thus offering a convenient reaction protocol. The catalytic reactivity was significantly improved by the electronic tuning of the bidentate LX ligands, and the observed regioselectivity was rationalized by the conformational analysis and DFT calculations of the transition states. The superior performance of the newly developed cobalt catalyst system could be broadly applied to both C(sp2)-H and C(sp3)-H carbamation reactions under mild conditions.
- Chang, Sukbok,Jung, Hoimin,Kim, Dongwook,Lee, Jeonghyo,Lee, Jia,Park, Juhyeon
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supporting information
p. 12324 - 12332
(2020/08/06)
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- Visible-Light-Induced Intramolecular C(sp2)-H Amination and Aziridination of Azidoformates via a Triplet Nitrene Pathway
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Catalytic intramolecular C-H amination and aziridination reactions of o-allylphenyl azidoformates have been achieved under visible-light irradiation, providing a mild, clean, and efficient method for the synthesis of useful benzoxazolones and [5.1.0] bicyclic aziridines. Mechanistic studies suggest that a triplet nitrene acts as the reactive intermediate. The chemoselectivity of the reaction, with alkyl olefin aziridination ? electron deficient olefin aziridination ≈ C(sp2)-H amination ? C(sp3)-H amination was observed, which may be instructive in the development of an understanding of visible-light-induced triplet nitrene transformation reactions.
- Zhang, Yipin,Dong, Xunqing,Wu, Yanan,Li, Guigen,Lu, Hongjian
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supporting information
p. 4838 - 4842
(2018/08/24)
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- Preparation of chloroformates using bis(trichloromethyl)carbonate
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The synthesis of eight chloroformates using bis(trichloromethyl) carbonate(BTC) is reported. It has been found that the yields by this BTC method are improved over the earlier phosgene method, and sodium hydroxide is better than pyridine as catalyst for the preparation of phenyl chloroformate.
- Shi, Haibo,Hu, Weixiao,Sun, Yaquan
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p. 708 - 709
(2007/10/03)
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- Heat-sensitive recording materials and phenol compounds
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Heat-sensitive recording materials contain an electron-donating chromogenic compound and an electron-attracting compound. The recording materials also contain at least one compound represented by the following formula: STR1 wherein R1 and R3 mean a hydrogen atom or an alkyl, aralkyl or aryl group, R2 and R4 denote an alkyl, alkenyl, aralkyl or aryl group, X1, X2, Y1 and Y2 stand for an oxygen or a sulfur atom, and --Z1 -- and --Z2 -- are a specific aromatic group. Also provided are phenol compounds represented by the following formula: STR2 wherein R1, R2, X1 and Y1 have the same meanings as defined above; R5 and R6 are a hydrogen or halogen atom or an alkyl, alkoxy, aralkyl, aryl or hydroxyl group; p and q stand for an integer of 1-4; R5 and R6 may be either the same or different when p and q represent an integer of 2 or greater; and --Z3 -- means a specific divalent group.
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