- Deoxygenative Amination of Azine-N-oxides with Acyl Azides via [3 + 2] Cycloaddition
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A transition-metal-free deoxygenative C-H amination reaction of azine-N-oxides with acyl azides is described. The initial formation of an isocyanate from the starting acyl azide via a Curtius rearrangement can trigger a [3 + 2] dipolar cycloaddition of polar N-oxide fragments to generate the aminated azine derivative. The applicability of this method is highlighted by the late-stage and sequential amination reactions of complex bioactive compounds, including quinidine and fasudil. Moreover, the direct transformation of aminated azines into various bioactive N-heterocycles illustrates the significance of this newly developed protocol.
- Ghosh, Prithwish,Han, Sang Hoon,Han, Sangil,Kim, Dongeun,Kim, In Su,Kim, Saegun,Kwon, Na Yeon,Mishra, Neeraj Kumar
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p. 2476 - 2485
(2020/03/13)
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- Visible Light-Induced Regioselective Cycloaddition of Benzoyl Azides and Alkenes to Yield Oxazolines
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Visible light catalysis allows the regioselective synthesis of oxazolines in high yields. The mild photosensitized manifold leverages the intermolecular formation of oxazolines with a wide functional group tolerance on both benzoyl azides and alkenes part
- Bellotti, Peter,Brocus, Julien,El Orf, Fatima,Selkti, Mohamed,K?nig, Burkhard,Belmont, Philippe,Brachet, Etienne
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supporting information
p. 6278 - 6285
(2019/05/24)
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- Palladium-Catalyzed One-Pot Synthesis of N -Sulfonyl, N -Phosphoryl, and N -Acyl Guanidines
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An efficient palladium-catalyzed cascade reaction of azides with isonitrile and amines is presented; it offers an alternative facile approach toward N -sulfonyl-, N -phosphoryl-, and N -acyl-functionalized guanidines in excellent yield. These series of substituted guanidines exhibit potential biological and pharmacological activities. In addition, the less reactive intermediate benzoyl carbodiimide could be isolated by silica gel column flash chromatography in moderate yield.
- Qiao, Guanyu,Zhang, Zhen,Huang, Baoliang,Zhu, Liu,Xiao, Fan,Zhang, Zhenhua
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supporting information
p. 330 - 340
(2018/01/12)
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- Iridium(III)-Catalyzed Selective and Mild C-H Amidation of Cyclic N-Sulfonyl Ketimines with Organic Azides
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A general protocol for iridium catalyzed direct C?H amidation of cyclic N-sulfonyl ketimines using sulfonyl, acyl and aryl azides as nitrogen source is reported herein. The reaction takes place at room temperature with acyl and aryl azides, while an elevated temperature needed with sulfonyl azides to furnish aminated sultams in excellent yields with complete chemo and regioselectivity, thus providing a robust and environmentally benign process to the synthesis of aminosultams. (Figure presented.).
- Maraswami, Manikantha,Chen, Gang,Loh, Teck-Peng
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supporting information
p. 416 - 421
(2017/11/13)
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- Visible light sensitization of benzoyl azides: Cascade cyclization toward oxindoles: Via a non-nitrene pathway
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Visible light sensitization of benzoyl azides was examined in reaction with N-phenylmethacrylamides to afford biologically important oxindoles and spirooxindoles via a cascade cyclization under mild reaction conditions. Mechanistic studies suggested a non-nitrene pathway, where triplet benzoyl azides act as the reactive intermediate.
- Bagal, Dattatraya B.,Park, Sung-Woo,Song, Hyun-Ji,Chang, Sukbok
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supporting information
p. 8798 - 8801
(2017/08/09)
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- Unprecedented Transformation of a Directing Group Generated in Situ and Its Application in the One-Pot Synthesis of 2-Alkenyl Benzonitriles
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An unprecedented protocol for the transformation of benzoyl azides into benzonitrile derivatives via iminophosphoranes generated in situ is described. The strategy was successfully applied to the de-novo synthesis of 2-alkenylated benzonitrile derivatives from benzoyl azides through ortho CH activation/alkenylation followed by subsequent rearrangement. The salient features of this protocol involve incorporation of two important functionalities through cyanation and olefination in one pot under mild reaction conditions by using a less expensive Ru catalyst. The mechanism was established by isolating and characterising (using 31PNMR) an intermediate with two ortho functionalities, iminophosphorane and olefin, under specific reaction conditions. Directly functional! Cyanation and olefination was accomplished in one pot from benzoyl azides through an unprecedented directing group transformation. The method generates benzonitriles and can be used for the synthesis of 2-alkenylated benzonitrile derivatives (see scheme).
- Kumar, Ravi,Arigela, Rajesh K.,Kundu, Bijoy
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p. 11807 - 11812
(2015/08/11)
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- Orthogonal reactivity of acyl azides in C-H activation: Dichotomy between C-C and C-N amidations based on catalyst systems
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The dual reactivity of acyl azides was utilized successfully in C-H activation by the choice of catalyst systems: while selective C-C amidation was achieved under thermal Rh catalysis, a Ru catalyst was found to mediate direct C-N amidation also highly se
- Shin, Kwangmin,Ryu, Jaeyune,Chang, Sukbok
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supporting information
p. 2022 - 2025
(2014/05/06)
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- The challenge of palladium-catalyzed aromatic azidocarbonylation: From mechanistic and catalyst deactivation studies to a highly efficient process
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Azidocarbonylation of iodoarenes with CO and NaN3, a novel Heck-type carbonylation reaction, readily occurs in an organic solvent-H 2O biphasic system to furnish aroyl azides at room temperature and 1 atm. The reaction is catalyzed by Xantphos-Pd and exhibits high functional group tolerance. The catalyst deactivation product, [(Xantphos)PdI2], can be reduced in situ with PMHS to Pd(0) to regain catalytic activity. In this way, the catalyst loading has been lowered to 0.2% without any losses in selectivity at nearly 100% conversion to synthesize a series of aroyl azides in 80-90% isolated yield on a gram scale. Alternatively, the ArCON3 product can be used without isolation for further transformations in situ, e.g., to isocyanates, ureas, benzamides, and iminophosphoranes. A detailed experimental and computational study has identified two main reaction pathways for the reaction. For both routes, Ar-I oxidative addition to Pd(0) is the rate-determining step. In the presence of CO in excess, the Ar-I bond is activated by the less electron-rich Pd center of a mixed carbonyl phosphine complex. Under CO-deficient conditions, a slightly lower energy barrier pathway is followed that involves Ar-I oxidative addition to a more reactive carbonyl-free (Xantphos)Pd0 species. Mass transfer in the triphasic liquid-liquid-gas system employed for the reaction plays an important role in the competition between these two reaction channels, uniformly leading to a common aroyl azido intermediate that undergoes exceedingly facile ArCO-N 3 reductive elimination. Safety aspects of the method have been investigated.
- Miloserdov, Fedor M.,McMullin, Claire L.,Belmonte, Marta Martinez,Benet-Buchholz, Jordi,Bakhmutov, Vladimir I.,Macgregor, Stuart A.,Grushin, Vladimir V.
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supporting information
p. 736 - 752
(2014/03/21)
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- Ir(III)-catalyzed mild C-H amidation of arenes and alkenes: An efficient usage of acyl azides as the nitrogen source
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Reported herein is the development of the Ir(III)-catalyzed direct C-H amidation of arenes and alkenes using acyl azides as the nitrogen source. This procedure utilizes an in situ generated cationic half-sandwich iridium complex as a catalyst. The reaction takes place under very mild conditions, and a broad range of sp2 C-H bonds of chelate group-containing arenes and olefins are smoothly amidated with acyl azides without the intervention of the Curtius rearrangement. Significantly, a wide range of reactants of aryl-, aliphatic-, and olefinic acyl azides were all efficiently amidated with high functional group tolerance. Using the developed approach, Z-enamides were readily accessed with a complete control of regio- and stereoselectivity. The developed direct amidation proceeds in the absence of external oxidants and releases molecular nitrogen as a single byproduct, thus offering an environmentally benign process with wide potential applications in organic synthesis and medicinal chemistry.
- Ryu, Jaeyune,Kwak, Jaesung,Shin, Kwangmin,Lee, Donggun,Chang, Sukbok
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supporting information
p. 12861 - 12868
(2013/09/23)
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- Palladium-catalyzed aromatic azidocarbonylation
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Aryl iodides smoothly react with NaN3 and CO in the presence of a Pd/Xantphos catalyst to give aroyl azides (ArCON3) in 75-92 % yield. The reaction occurs under mild reaction conditions (1 atm, 20-50 °C) and exhibits high functional-group tolerance. (Xantphos=9,9-dimethyl-4,5- bis(diphenylphosphino)xanthene)
- Miloserdov, Fedor M.,Grushin, Vladimir V.
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supporting information; experimental part
p. 3668 - 3672
(2012/05/20)
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- Rapid construction of isatin derivatives via addition of bis(alkylthio)carbenes to aryl isocyanates
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Thermally induced cyclization between bis(alkylthio)carbenes, derived from the corresponding oxadiazolines, and substituted aryl isocyanates provides access to a variety of isatin derivatives with good efficiency.
- Rigby, James H.,Danca, M. Diana
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p. 6891 - 6894
(2007/10/03)
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