- One-Pot Tandem ortho-Naphthoquinone-Catalyzed Aerobic Nitrosation of N-Alkylanilines and Rh(III)-Catalyzed C-H Functionalization Sequence to Indole and Aniline Derivatives
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The nitroso group served as a traceless directing group for the C-H functionalization of N-alkylanilines, ultimately removed after functioning either as an internal oxidant or under subsequent reducing conditions. The unique ability of o-NQ catalysts to aerobically oxidize the N-alkylanilines without using solvents and stoichiometric amounts of oxidants has rendered the new opportunity to develop the telescoped catalyst systems without a need for directly handling the hazardous N-nitroso compounds.
- Si, Tengda,Kim, Hun Young,Oh, Kyungsoo
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p. 1152 - 1163
(2021/01/14)
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- Rhodium-catalyzed tandem acylmethylation/annulation ofN-nitrosoanilines with sulfoxonium ylides for the synthesis of substituted indazoleN-oxides
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An atom-economical protocol for synthesizing indazoleN-oxides from readily availableN-nitrosoanilines and sulfoxonium ylides through the rhodium(iii)-catalyzed C-H activation and cyclization reaction is described here. This protocol employs nitroso as a traceless directing group. The transformation features powerful reactivity, tolerates various functional groups, and proceeds with moderate to good yields under an ambient atmosphere, providing a straightforward approach to access structurally diverse and valuable indazoleN-oxide derivatives. Importantly, this new annulation process represents a hitherto unobserved reactivity pattern for theN-nitroso group.
- Cui, Xin-F,Huang, Guo-Sh
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supporting information
p. 4014 - 4018
(2020/06/09)
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- Rh(iii)-catalyzed, hydrazine-directed C-H functionalization with 1-alkynylcyclobutanols: A new strategy for 1: H -indazoles
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Rh(iii)-catalyzed coupling of phenylhydrazines with 1-alkynylcyclobutanols was realized through a hydrazine-directed C-H functionalization pathway. This [4+1] annulation, based on the cleavage of a Csp-Csp triple bond in alkynylcyclobutanol, provides a new pathway to prepare diverse 1H-indazoles under mild reaction conditions. This journal is
- Zhang, Lei,Chen, Junyu,Chen, Xiahe,Zheng, Xiangyun,Zhou, Jian,Zhong, Tianshuo,Chen, Zhiwei,Yang, Yun-Fang,Jiang, Xinpeng,She, Yuan-Bin,Yu, Chuanming
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supporting information
p. 7415 - 7418
(2020/07/15)
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- Cp?Rh(iii) catalyzed: Ortho -halogenation of N -nitrosoanilines by solvent-controlled regioselective C-H functionalization
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We present a novel, efficient, and regioselective method for the rhodium-catalyzed direct C-H ortho-halogenation of anilines that involves a removable N-nitroso directing group. This method featured mild reaction conditions, wide substrate scope, good functional group tolerance and satisfactory yields. To maintain the high ortho-regioselectivity and conversion, increasing the steric hindrance of the solvent was critical. Preliminary mechanistic studies suggest that C-H activation may be involved in the rate-determining step.
- Peng, Qiujun,Hu, Jian,Huo, Jiyou,Yuan, Hongshun,Xu, Lanting,Pan, Xianhua
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p. 4471 - 4481
(2018/06/29)
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- Rhodium-catalyzed oxidative C-H/C-H cross-coupling of aniline with heteroarene: N-nitroso group enabled mild conditions
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The development of transition metal-catalyzed oxidative C-H/C-H cross-coupling between two (hetero)arenes to forge aryl-heteroaryl motifs under mild conditions is an appealing yet challenging task. Herein, we disclose a rhodium-catalyzed oxidative C-H/C-H cross-coupling reaction of an N-nitrosoaniline with a heteroarene under mild conditions. The judicious choice of the N-nitroso group as a directing group enables heightened reactivity. The coupled products could be transformed expediently to (2-aminophenyl)heteroaryl skeletons.
- He, Shuang,Tan, Guangying,Luo, Anping,You, Jingsong
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supporting information
p. 7794 - 7797
(2018/07/25)
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- Highly selective sp3 C-N bond activation of tertiary anilines modulated by steric and thermodynamic factors
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A highly selective sp3 C-N cleavage of tertiary anilines was achieved using the TBN/TEMPO catalyst system. When N,N-diaklylanilines (alkyl, benzyl) were employed, the N-CH3 bond was selectively cleaved via radical C-H activation. Moreover, when the allyl group was installed, totally reverse selectivity was observed. It is worth noting that the solvent effect is also crucial to obtain high reaction efficiency and selectivity.
- Jia, Xiaodong,Li, Pengfei,Shao, Yu,Yuan, Yu,Ji, Honghe,Hou, Wentao,Liu, Xiaofei,Zhang, Xuewen
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supporting information
p. 5568 - 5574
(2017/12/06)
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- Palladium-catalyzed ortho-acylation of N-Nitrosoanilines with α-oxocarboxylic acids: A convenient method to synthesize N-Nitroso ketones and indazoles
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An efficient and mild protocol for regioselective synthesis of N-Nitroso aryl ketones by palladium-catalyzed direct acylation of arenes using N-Nitroso as directing groups is described. This reaction proceeded smoothly and could tolerate a variety of functional groups. Moreover, this chemistry offers a convenient access to a range of indazoles.
- Zhang, Liang,Wang, Zhe,Guo, Peiyu,Sun, Wei,Li, Ya-Min,Sun, Meng,Hua, Chengwen
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supporting information
p. 2511 - 2514
(2016/05/24)
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- Copper(II)-catalyzed oxidative N-nitrosation of secondary and tertiary amines with nitromethane under an oxygen atmosphere
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The combination of a catalytic amount of Cu(OTf)2 and less than a stoichiometric amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under an O2 atmosphere effectively promoted the N-nitrosation of both secondary aromatic/aliphatic amines and tertiary aromatic amines with nitromethane (CH3NO2) leading to the preparation of N-nitrosamine derivatives.
- Sakai, Norio,Sasaki, Minoru,Ogiwara, Yohei
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p. 11638 - 11641
(2015/07/15)
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- Palladium-catalyzed oxidative C-H bond acylation of N-nitrosoanilines with toluene derivatives: A traceless approach to synthesize N-alkyl-2-aminobenzophenones
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A palladium-catalyzed cascade cross-coupling of N-nitroso-anilines and toluene derivatives for the direct synthesis of N-alkyl-2-aminobenzophenones is described. N-nitroso groups in anilines can act as the traceless directing groups while toluene derivatives can serve as effective acyl precursors under mild reaction conditions.
- Wu, Yinuo,Feng, Ling-Jun,Lu, Xiao,Kwong, Fuk Yee,Luo, Hai-Bin
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supporting information
p. 15352 - 15354
(2015/01/08)
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- Rhodium(III)-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate for cycloaddition/fragmentation synthesis of indazoles
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RhIII-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate allows subsequent construction of indazoles, a privileged heterocycle scaffold in synthetic chemistry, through the exploitation of reactivity between the directing group and installed group. The formal [2+2] cycloaddition/fragmentation reaction pathway identified herein, a unique reactivity pattern hitherto elusive for the N-nitroso group, emphasizes the importance of forward reactivity analysis in the development of useful C-H functionalization-based synthetic tools. The synthetic utility of the protocol is demonstrated with the synthesis of a tri-cyclic-fused ring system. The diversity of covalent linkages available for the nitroso group should enable the extension of the genre of reactivity reported herein to the synthesis of other types of heterocycles.
- Chen, Jinsen,Chen, Pei,Song, Chao,Zhu, Jin
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supporting information
p. 14245 - 14249
(2015/02/05)
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- Iodide-catalyzed synthesis of N-nitrosamines via C-N cleavage of nitromethane
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An iodide-catalyzed process to synthesize N-nitrosamines has been developed using TBHP as the oxidant. The mild catalytic system succeeded in cleaving the carbon-nitrogen bond in nitromethane. This methodology uses commercially available, inexpensive catalysts and oxidants and has a wide substrate scope and operational simplicity.
- Zhang, Jie,Jiang, Jiewen,Li, Yuling,Wan, Xiaobing
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p. 11366 - 11372
(2013/12/04)
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- Rhodium(III)-catalyzed indole synthesis using N-N bond as an internal oxidant
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We report herein a Rh(III)-catalyzed cyclization of N-nitrosoanilines with alkynes for streamlined synthesis of indoles. The synthetic protocol features a distinct internal oxidant, N-N bond, as a reactive handle for catalyst turnover, as well as a hitherto tantalizingly elusive intermolecular redox-neutral manifold, predicated upon C-H activation, for the formation of a five-membered azaheterocycle. The compatibility of seemingly dichotomous acidic and basic conditions ensures reaction versatility for multifarious synthetic contexts. The tolerance of an array of auxiliary functional groups potentially permits predefined, programmable substitution patterns to be incorporated into the indole scaffold. Comprehensive mechanistic studies, under acidic condition, support [RhCp*]2+ as generally the catalyst resting state (switchable to [RhCp*(OOCtBu)]+ under certain circumstance) and C-H activation as the turnover-limiting step. Given the variety of covalent linkages available for the nitroso group, this labile functionality is likely to be harnessed as a generic handle for strikingly diverse coupling reactions.
- Liu, Baoqing,Song, Chao,Sun, Chao,Zhou, Shuguang,Zhu, Jin
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supporting information
p. 16625 - 16631
(2013/12/04)
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- N-Dealkylation-N-nitrosation of Tertiary Aromatic Amines by n-Butyl Nitrite
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N,N-Dialkyl aromatic amines with a variety of ring substituents are N-dealkylated and N-nitrosated efficiently by n-butyl nitrite/ammonium chloride/water at reflux temperature.Ring nitrosation was never observed, but minor amounts of m- and p-nitro amines and/or nitrosamines were formed in some cases.Ring nitration is rather a reaction of the initial substrate than a process occurring on formed nitrosamines.The leaving propensities of the initial N-substituents to yield nitrosamines were in the order benzyl >> methyl >> alkyl.Key Words: Nitrosamines; N-Dealkylation; N-Nitrosation; C-Nitration; Alkyl nitrite.
- Verardo, Giancarlo,Giumanini, Angelo G.,Strazzolini, Paolo
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p. 7845 - 7852
(2007/10/02)
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- AROMATIC TERTIARY AMINES AND n-BUTYL NITRITE
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The reaction between alkyl nitrites, particularly n-butyl nitrite, and tertiary aromatic amines under a variety of experimental conditions promptly yielded products of N-dealkylation-N-nitrosation, ring nitration, ipso-substitution and, occasionally, combinations of these processes.Aminoethers were detected as final products and intermediates on the way to N-nitrosations.Reaction pathways are suggested for some of the observed behaviours on the basis of experimental evidences whereas other alternatives are discarded.
- Varardo, Giancarlo,Giumanini, Angelo G.,Strazzolini, Paolo
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p. 4303 - 4332
(2007/10/02)
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