- Access to Branched Allylarenes via Rhodium(III)-Catalyzed C-H Allylation of (Hetero)arenes with 2-Methylidenetrimethylene Carbonate
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A rhodium(III)-catalyzed C-H allylation of (hetero)arenes by using 2-methylidenetrimethylene carbonate as an efficient allylic source has been developed for the first time. Five different directing groups including oxime, N-nitroso, purine, pyridine, and pyrimidine were compatible, delivering various branched allylarenes bearing an allylic hydroxyl group in moderate to excellent yields.
- Zhang, Shang-Shi,Zheng, Yi-Chuan,Zhang, Zi-Wu,Chen, Shao-Yong,Xie, Hui,Shu, Bing,Song, Jia-Lin,Liu, Yan-Zhi,Zeng, Yao-Fu,Zhang, Luyong
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supporting information
p. 5719 - 5723
(2021/08/16)
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- Direct Oxygenation of C-H Bonds through Photoredox and Palladium Catalysis
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This report presents the oxygenation of C-H bonds via the merger of photocatalysis and Pd catalysis. Herein, we describe the utilization of a photocatalyst to oxidize an organopalladium(II) intermediate to high-valent PdIII or PdIV intermediates, which promotes the formation of C-O bonds. The demonstrated method works efficiently with various directing groups, such as oxime ether and benzothiazole. The applicability of this direct C-O bond formation method is shown by synthesizing several metal complexes of 2-(benzo[d]thiazol-2-yl)phenol that can be used in organic light-emitting diodes and pharmaceuticals.
- Paul, Amrita,Shah, Sk. Sheriff,Shee, Maniklal,Singh, Amit Kumar,Singh, N. D. Pradeep
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p. 3426 - 3439
(2020/03/23)
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- Regio-Divergent C—H Alkynylation with Janus Directing Strategy via Ir(III) Catalysis
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Directing strategy has been extensively exploited to maintain activity and selectivity for the rapid access to functionalized molecules and pharmaceutical targets. However, ‘one-to-one’ activation model was usually achieved through traditional directing strategy. Herein, we achieved ‘one-to-two’ activation model by slight modification of simple and practical ketoxime and amide functionality. With judicious choice of directing groups, Csp3—H and Csp2—H bond alkynylation reaction, and more significantly, dehydrogenative Csp3—H alkynylation, were realized, enabling the regio-divergent late-stage modifications of pharmaceuticals.
- Li, Xianwei,Liang, Guangxin,Shi, Zhang-Jie
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supporting information
p. 929 - 934
(2020/06/02)
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- Nitrate promoted mild and versatile Pd-catalysed C(sp2)-H oxidation with carboxylic acids
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A nitrate-promoted Pd-catalysed mild cross-dehydrogenative C(sp2)-H bond oxidation of oximes or azobenzenes with diverse carboxylic acids has been developed. In contrast to the previous catalytic systems, this protocol features mild conditions (close to room temperature for most cases) and a broad substrate scope (up to 64 examples), thus constituting a versatile method to directly prepare diverse O-aryl esters. Moreover, the superiority of the nitrate additive in this mild transformation was further determined by experimental and computational evidence.
- Hao, Hong-Yan,He, Yu-Ting,Lou, Shao-Jie,Luo, Gen,Mao, Yang-Jie,Xiong, Xue,Xu, Dan-Qian,Xu, Zhen-Yuan
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supporting information
p. 6732 - 6737
(2020/09/21)
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- Rhodium(III)-Catalyzed Oxidative Annulation of Ketoximes with Sulfonamide: A Direct Approach to Indazoles
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A rhodium(III)-catalyzed intermolecular C-H amination of ketoxime and iodobenzene diacetate-enabled N-N bond formation in the synthesis of indazoles has been developed. A variety of functional groups were well tolerated, providing the corresponding produc
- Wang, Ning,Liu, Lingling,Xu, Wentao,Zhang, Mengye,Huang, Zhibin,Shi, Daqing,Zhao, Yingsheng
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supporting information
(2019/01/21)
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- Rhodium(III)-Catalyzed Oxidative Annulation of Ketoximes with Sulfonamide: A Direct Approach to Indazoles
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A rhodium(III)-catalyzed intermolecular C-H amination of ketoxime and iodobenzene diacetate-enabled N-N bond formation in the synthesis of indazoles has been developed. A variety of functional groups were well tolerated, providing the corresponding products in moderate to good yields. Moreover, the nitro-substituted ketoximes are well compatible in this reaction, leading to the corresponding products in moderate to good yields.
- Wang, Ning,Liu, Lingling,Xu, Wentao,Zhang, Mengye,Huang, Zhibin,Shi, Daqing,Zhao, Yingsheng
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supporting information
p. 365 - 368
(2019/01/24)
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- Reusable Palladium Nanoparticles Catalyzed Oxime Ether Directed Mono Ortho-Hydroxylation under Phosphine Free Neutral Condition
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An efficient, reusable and stable binaphthyl stabilized Pd-nanoparticles (Pd-BNP) catalyzed the direct ortho-C?H hydroxylation of acetophenone oxime ethers under neutral and phosphine ligand-free condition has been developed. A readily available, economic, safe and greener oxidant oxone has been used in this direct ortho-hydroxylation. The scope of the reaction has been studied with various acetophenone oxime ethers including electron rich to electron deficient system and the reaction afforded only mono hydroxylated products in a highly regioselective manner. Several control experiment results confirmed that the oxone is the hydroxyl source. The Pd-BNP catalyst has been reused up to five times. The heterogeneous test confirmed that the reaction is catalyzed by the heterogeneous Pd-BNP catalyst. (Figure presented.).
- Saha, Rajib,Perveen, Naziya,Nihesh, Naorem,Sekar, Govindasamy
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supporting information
p. 510 - 519
(2018/12/11)
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- Catalyst-Controlled [3 + 2] and [4 + 2] Annulations of Oximes with Propargyl Alcohols: Divergent Access to Indenamines and Isoquinolines
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Rhodium(III)- and iridium(III)-catalyzed C-H activation of oximes and coupling with propargyl alcohols is discussed. Depending on the catalyst, the reaction pathway switched between [3 + 2] and [4 + 2] annulations, thus giving divergent access to indenami
- Gong, Wanchun,Zhou, Zhi,Shi, Jingjing,Wu, Bo,Huang, Biyun,Yi, Wei
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supporting information
p. 182 - 185
(2018/01/17)
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- Palladium-Catalyzed C(sp2)-H Acetoxylation via Electrochemical Oxidation
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Palladium-catalyzed arene C(sp2)-H acetoxylation has emerged as a powerful tool to construct a carbon-oxygen (C-O) bond. However, the requirement of stoichiometric chemical oxidants for this transformation possesses a significant disadvantage.
- Li, Yi-Qian,Yang, Qi-Liang,Fang, Ping,Mei, Tian-Sheng,Zhang, Dayong
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supporting information
p. 2905 - 2908
(2017/06/07)
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- Synthesis of 2-fluorocholine aryl carbonyl compounds
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The invention provides a method for synthesizing 2-fluoroarylcarbonyl compounds, which comprises the following steps: converting arylcarbonyl compounds into corresponding carbonyl oxime ether compounds, mildly implementing aryl hydrocarbon chain direct fluoridation of high-selectivity oximido substituent group ortho-position in the presence of a palladium catalyst, a fluoridation reagent and additives, and finally, rehydrolyzing oxime ethers under the action of acid to obtain the 2-fluoroarylcarbonyl compounds. The fluoridation method has the advantages of mild reaction conditions, high substrate adaptability, high fluoridation selectivity and the like, is simple to operate, and has higher application research value.
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Paragraph 0050
(2017/02/09)
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- NHPI and palladium cocatalyzed aerobic oxidative acylation of arenes through a radical process
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The NHPI and palladium cocatalyzed radical oxidative acylation of arenes with aldehydes and alcohols as acyl equivalents via selective C-H functionalization has been described. Molecular oxygen, the most environmentally friendly oxidant, was used as the terminal oxidant in this catalytic cycle.
- Liang, Yu-Feng,Wang, Xiaoyang,Tang, Conghui,Shen, Tao,Liu, Jianzhong,Jiao, Ning
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supporting information
p. 1416 - 1419
(2016/01/25)
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- B(C6F5)3-catalyzed hydrogenation of oxime ethers without cleavage of the N-O bond
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The hydrogenation of oximes and oxime ethers is usually hampered by N-O bond cleavage, hence affording amines rather than hydroxylamines. The boron Lewis acid B(C6F5)3 is found to catalyze the chemoselective hydrogenation
- Mohr, Jens,Oestreich, Martin
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supporting information
p. 13278 - 13281
(2015/01/16)
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- Direct C-H amination of arenes with alkyl azides under rhodium catalysis
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New horizons in the utility of azides: The rhodium-catalyzed intermolecular direct C-H amination of arenes with alkyl azides provides a convenient route to N-alkyl anilines (see scheme; DG=directing group). Alkyl azides with a wide range of functional groups reacted readily with various substrates, including benzamides, aromatic ketones, and flavones. Copyright
- Shin, Kwangmin,Baek, Yunjung,Chang, Sukbok
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supporting information
p. 8031 - 8036
(2013/08/23)
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- [Cp*RhCl2]2-catalyzed ortho-C-H bond amination of acetophenone o-methyloximes with primary N-chloroalkylamines: Convenient synthesis of N-alkyl-2-acylanilines
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Rh(iii)-catalyzed aromatic C-H amination of acetophenone o-methyloximes with primary N-chloroalkylamines was developed, and the arylamine products were obtained in up to 92% yield. The reaction probably involves rate-limiting electrophilic C-H bond cleavage (kH/kD = 2).
- Ng, Ka-Ho,Zhou, Zhongyuan,Yu, Wing-Yiu
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supporting information
p. 7031 - 7033
(2013/09/02)
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- Rhodium(III)-catalyzed intermolecular direct amination of aromatic C-H bonds with N-chloroamines
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A Rh(III)-catalyzed direct aromatic C-H amination is achieved using N-chloroamines as a reagent. Furthermore, we also developed a one-pot amination protocol involving in situ chlorination of the secondary amines. The catalytic amination operates at mild conditions with excellent functional group tolerance and regioselectivity.
- Ng, Ka-Ho,Zhou, Zhongyuan,Yu, Wing-Yiu
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supporting information; experimental part
p. 272 - 275
(2012/02/04)
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- Rhodium-catalyzed intermolecular amidation of arenes with sulfonyl azides via chelation-assisted C-H bond activation
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We report the direct amidation of arene C-H bonds using sulfonyl azides as the amino source to release N2 as the single byproduct. The reaction is catalyzed by a cationic rhodium complex under external oxidant-free conditions in the atmospheric environment. A broad range of chelate group-containing arenes are selectively amidated with excellent functional group tolerance, thus opening a new avenue to practical intermolecular C-N bond formation.
- Kim, Ji Young,Park, Sae Hume,Ryu, Jaeyune,Cho, Seung Hwan,Kim, Seok Hwan,Chang, Sukbok
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supporting information; experimental part
p. 9110 - 9113
(2012/07/14)
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- Rh(III)-catalyzed oxidative coupling of unactivated alkenes via C-H activation
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Oxime directed aromatic C-H bond activation and oxidative coupling to alkenes is reported using a cationic Rh(III) catalyst. Significantly, the method can be used to oxidatively couple unactivated, aliphatic alkenes.
- Tsai, Andy S.,Brasse, Mikael,Bergman, Robert G.,Ellman, Jonathan A.
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supporting information; experimental part
p. 540 - 542
(2011/03/23)
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- Direct sequential C-O and C-C formation via double sp2 C-H bond activations to construct 6H-benzo[c]chromen-6-ones
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A new method for the direct ortho acyloxylation of sp2 C-H bond with various carboxylic acids was developed. A novel strategy to synthesize 6H-benzo[c]chromen-6-one derivatives was designed via Pd-catalyzed double activations of adjacent spsup
- Sun, Chang-Liang,Liu, Jia,Wang, Yang,Zhou, Xiao,Li, Bi-Jie,Shi, Zhang-Jie
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supporting information; experimental part
p. 883 - 886
(2011/06/17)
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- Pd-catalyzed ortho-C-H acylation/cross coupling of aryl ketone O-methyl oximes with aldehydes using tert-butyl hydroperoxide as oxidant
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A Pd-catalyzed protocol for direct C-H bond acylation by cross coupling of aryl ketone oximes and aldehydes using tert-butyl hydroperoxide (TBHP) as oxidant was developed. With oximes as a directing group for the C-H activation, the coupling with aldehydes was achieved with remarkable regioselectivity. The acylation reactions exhibit excellent functional group tolerance, and both aliphatic and heteroaromatic aldehydes can be effectively coupled to the oximes.
- Chan, Chun-Wo,Zhou, Zhongyuan,Chan, Albert S. C.,Yu, Wing-Yiu
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supporting information; experimental part
p. 3926 - 3929
(2010/11/19)
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- One-pot synthesis of oxime ethers from benzaldehyde or acetophenone, hydroxylamine salt, potassium hydroxide, and alkyl halides
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Oxime ethers were synthesized in one-pot reaction from benzaldehyde or acetophenone, hydroxylamine hydrogen chloride, alkyl halides and KOH in aqueous DMSO. The reactions were completed in 15-50 min with yields in 80-96%.
- Li, Chunbao,Zhang, Hang,Cui, Yi,Zhang, Shuanming,Zhao, Zheyuan,Choi, Michael C. K.,Chan, Albert S. C.
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p. 543 - 546
(2007/10/03)
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- Reaction of Oximes with Dimethyl Carbonate: A New Entry to 3-Methyl-4,5-disubstituted-4-oxazolin-2-ones
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The reaction of ketone oximes with dimethyl carbonate (DMC) carried out in an autoclave at 180-190 deg C and in the presence of K2CO3 yields 3-methyl-4,5-disubstituted-4-oxazolin-2-ones.The reaction can be applied to both aliphatic and aromatic ketone oximes, provided that a methylene group be present near the C=N bond.Nonoptimized yields range from 22 to 48percent.The reaction seems to be a sigmatropic rearrangement where DMC plays a key role in causing the initial N-methylation of the oximes.
- Marques, C. A.,Selva, M.,Tundo, P.,Montanari, F.
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p. 5765 - 5770
(2007/10/02)
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- The Geometry of Displacements at Nonstereogenic Atoms: The Formal Displacement of Alkoxide from Alkoxyamines by Organolithium Reagents
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Amination of organolithium regents can be achieved by reaction with methyllithium-alkoxyamines.Details of the methodology and analysis of the reaction mechanism are presented.Reactions of methyl-, ethyl-, n-butyl-, sec-butyl-, tert-butyl-, phenyl-, and (o-methoxyphenyl)lithium with methyllithium-methoxyamine give the corresponding amines, isolated as the benzamides, in yields of 71-97percent.Lower yields are obtained with o-lithio-N,N-diisopropylbenzamide, 4-lithiodibenzothiophene, n-butylmagnesium bromide, and phenylmagnesium bromide.Reactions of n-butyl, sec-butyl-, tert-butyl-, and phenyllithium with methyllithium-N-methylmethoxyamine provide the corresponding N-methyl-amines, isolated as the benzamides, in yields of 30-70percent.Retention of the N-methyl group in these reactions is considered to rule out a nitrene intermediate.Involvement of a lithium alkoxyamide is suggested by the formation and substitution of that species by two different routes.Dilithiation of N-methoxy-N-amine (17) gives, after an intramolecular reaction and addition of acetyl chloride, N-acetylindoline, in 78percent yield.Dilithiation of N-methyl-N-amine (19) gives N-methyl-N-acetamide (20), after rection with acetyl chloride.The nitrogen transfer in this conversion is shown by a double labeling experiment to be intermolecular.This results is taken to suggest that the bond angles required for displacement cannot be achieved in a six-membered ring, and the mechanism of the reaction involves a complex in which displacement occurs via an SN2-like transition state.The exocyclic-endocyclic intramolecular-intermolecular test is noted to provide a general approach for determination of the geomatry of reactions at nonstereogenic centers.
- Beak, Peter,Basha, Anwer,Kokko, Bruce,Loo, DeKai
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p. 6016 - 6023
(2007/10/02)
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