- Catalytic Decarboxylative C?N Formation to Generate Alkyl, Alkenyl, and Aryl Amines
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Transition-metal-catalyzed sp2 C?N bond formation is a reliable method for the synthesis of aryl amines. Catalytic sp3 C?N formation reactions have been reported occasionally, and methods that can realize both sp2 and sp3 C?N formation are relatively unexplored. Herein, we address this challenge with a method of catalytic decarboxylative C?N formation that proceeds through a cascade carboxylic acid activation, acyl azide formation, Curtius rearrangement and nucleophilic addition reaction. The reaction uses naturally abundant organic carboxylic acids as carbon sources, readily prepared azidoformates as the nitrogen sources, and 4-dimethylaminopyridine (DMAP) and Cu(OAc)2 as catalysts with as low as 0.1 mol % loading, providing protected alkyl, alkenyl and aryl amines in high yields with gaseous N2 and CO2 as the only byproducts. Examples are demonstrated of the late-stage functionalization of natural products and drug molecules, stereospecific synthesis of useful α-chiral alkyl amines, and rapid construction of different ureas and primary amines.
- Zhang, Yipin,Ge, Xia,Lu, Hongjian,Li, Guigen
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supporting information
p. 1845 - 1852
(2020/12/01)
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- 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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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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p. 4838 - 4842
(2018/08/24)
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- Copper(I)-Catalyzed Synthesis of 1,4-Disubstituted 1,2,3-Triazoles from Azidoformates and Aryl Terminal Alkynes
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The copper(I)-catalyzed azide-alkyne cycloaddition reaction has been extensively studied and widely applied in organic synthesis. However, the formation of 1,2,3-triazoles with electron-deficient azide has been a challenging problem. In this report, we ha
- Lee, Heejin,Lee, Jae Kyun,Min, Sun-Joon,Seo, Hyeonglim,Lee, Youngbok,Rhee, Hakjune
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p. 4805 - 4811
(2018/04/26)
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- Cesium Carboxylate-Promoted Iridium Catalyzed C-H Amidation/Cyclization with 2,2,2-Trichloroethoxycarbonyl Azide
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An Ir(III)-catalyzed direct C-H amidation/cyclization of benzamides using 2,2,2-trichloroethoxycarbonyl azide (TrocN3) as the aminocarbonyl source is reported. With the aid of cesium carboxylate, the reactions proceed efficiently and with high regioselectivity, producing various functionalized quinazoline-2,4(1H,3H)-diones, which are important building blocks and key synthetic intermediates for biologically and medicinally important compounds. During the reactions, two new C-N bonds were formed by breaking C-H and N-H bonds sequence.
- Zhang, Tao,Wang, Zhen,Hu, Xuejiao,Yu, Meng,Deng, Tianning,Li, Guigen,Lu, Hongjian
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p. 4898 - 4905
(2016/07/06)
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- A facile synthesis of azidoformate via chloroformate
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This work synthesized chloroformates by slowly adding alcohols into a suspension of trichloromethyl chloroformate, instead of phosgene, along with activated charcoal in tetrahydrofuran. This chloroformylation yielded chloroformates in near quantitative yield. The subsequent reaction between chloroformates and sodium azide in dry acetone produced azidoformates in a high yield.
- Wu, Pei-Lin,Su, Chia-Hao,Gu, Yi-Jeng
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p. 271 - 274
(2007/10/03)
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- A PARTICULARLY CONVENIENT ONE-POT SYNTHESIS OF N-ALKOXYCARBONYL, N-ACYL AND N-AROYL SUBSTITUTED IMINOPHOSPHORANES; IMPROVED PREPARATION OF AZIDOFORMATES, AROYL AND ALKANOYL AZIDES; AN ALTERNATIVE ROUTE TO COMPLEX AMIDES
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Chloroformates and acid chlorides react smoothly with sodium azide in acetone at 0 deg C, forming azidoformates, aroyl and alkanoyl azides in very high yield.With triphenylphosphine or other phosphines present in the reaction mixture, the forming azides are intercepted, leading directly to the corresponding N-alkanoyl, N-aroyl, N-alkoxycarbonyl, and N-aryloxycarbonyliminophosphoranes.N-acyliminophosphoranes react with n-butyllithium forming anions which react readily with electrophiles, e.g., carbonyl compounds, forming highly substituted iminophosphoranes.The phosphonium group is effortlessly removed from the latter compounds by acid hydrolysis forming the corresponding amides in high yield.Key words: Synthesis; iminophosphoranes; aroyl azides; alkanoyl azides; complex amides.
- Froeyen, Paul
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p. 161 - 172
(2007/10/02)
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