- Synthesis of Acyl Phosphoramidates Employing a Modified Staudinger Reaction
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A one-step synthesis of acyl phosphoramidates from a variety of functionalized acyl azides has been developed employing trimethylsilyl chloride as an activating agent in a modified Staudinger reaction. The methodology was further adapted to include the in situ generation of the acyl azides from a diverse selection of carboxylic acids and hydrazide starting synthons. The reaction scope was extended to include the synthesis of imidodiphosphates and the natural product Microcin C.
- Currie, Iain,Sleebs, Brad E.
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supporting information
p. 464 - 468
(2021/02/03)
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- Direct conversion of carboxylic acids to various nitrogen-containing compounds in the one-pot exploiting curtius rearrangement
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Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.
- Kumar, Arun,Kumar, Naveen,Sharma, Ritika,Bhargava, Gaurav,Mahajan, Dinesh
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p. 11323 - 11334
(2019/09/10)
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- Synthesis of Acyl Azides from 1,3-Diketones via Oxidative Cleavage of Two C-C Bonds
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A metal-free PhI(OAc)2-mediated method for the synthesis of acyl azides through oxidative cleavage of 1,3-diketones is described. This method is shown to have a broad substrate scope, providing a useful tool for multiproduct synthesis in a single procedure. A possible reaction pathway is proposed based on mechanistic studies.
- Yu, Tian-Yang,Zheng, Zhao-Jing,Dang, Tong-Tong,Zhang, Fang-Xia,Wei, Hao
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p. 10589 - 10594
(2018/09/06)
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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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- Visible light C-H amidation of heteroarenes with benzoyl azides
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Benzoyl azides were used for the direct and atom economic C-H amidation of electron rich heteroarenes in the presence of phosphoric acid, a photocatalyst and visible light. Hetero-aromatic amides are obtained in good yields at very mild reaction conditions with dinitrogen as the only by-product. The reaction allows the use of aryl-, heteroaryl- or alkenyl acyl azides and has a wide scope for heteroarenes, including pyrroles, indole, furan, benzofuran and thiophene giving good regio-selectivities and yields.
- Brachet,Ghosh,Ghosh,K?nig
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supporting information
p. 987 - 992
(2015/02/19)
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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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- 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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- Reinterpretation of curved hammett plots in reaction of nucleophiles with aryl benzoates: Change in rate-determining step or mechanism versus ground-state stabilization
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A kinetic study is reported for the reaction of the anionic nucleophiles OH-, CN-, and N3- with aryl benzoates containing substituents on the benzoyl as well as the aryloxy moiety, in 80 mol % H2O-20 mol % dimethyl sulfoxide at 25.0 °C. Hammett log k vs σ plots for these systems are consistently nonlinear. However, a possible traditional explanation in terms of a mechanism involving a tetrahedral intermediate with curvature resulting from a change in rate-determining step is considered but rejected. The proposed explanation involves ground-state stabilization through resonance interaction between the benzoyl substituent and the electrophilic carbonyl center in the two-stage mechanism. Accordingly, the data are nicely accommodated on the basis of the Yukawa-Tsuno equation, which gives linear plots for all three nuceophiles. Literature reports of the mechanism of acyl transfer processes are reconsidered in this light.
- Um, Ik-Hwan,Han, Hyun-Joo,Ahn, Jung-Ae,Kang, Swan,Buncel, Erwin
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p. 8475 - 8480
(2007/10/03)
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