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1.
Enantioselective CH Bond Functionalization Triggered by Radical Trifluoromethylation of Unactivated Alkene 下载免费PDF全文
Peng Yu Jin‐Shun Lin Lei Li Sheng‐Cai Zheng Ya‐Ping Xiong Li‐Jiao Zhao Prof. Dr. Bin Tan Prof. Dr. Xin‐Yuan Liu 《Angewandte Chemie (International ed. in English)》2014,53(44):11890-11894
An asymmetric unactivated alkene/C? H bond difunctionalization reaction for the concomitant construction of C? CF3 and C? O bonds was realized by using a Cu/Brønsted acid cooperative catalytic system, thus providing facile access to valuable chiral CF3‐containing N,O‐aminals with excellent regio‐, chemo‐, and enantioselectivity. Mechanistic studies revealed that this reaction may proceed by an unprecedented 1,5‐hydride shift involving activation of unactivated alkenes and a radical trifluoromethylation to initiate subsequent enantioselective functionalization of C? H bonds. Control experiments also suggested that chiral Brønsted acid plays multiple roles and not only controls the stereoselectivity but also increases the reaction rate through activation of Togni’s reagent. 相似文献
2.
Transition Metal‐Catalyzed Carbonylative CH Bond Functionalization of Arenes and C(sp3)H Bond of Alkanes 下载免费PDF全文
Sandip T. Gadge Prashant Gautam Bhalchandra M. Bhanage 《Chemical record (New York, N.Y.)》2016,16(2):835-856
In this article, we present the progress made in the area of carbonylative C? H functionalization, with special emphasis on arenes and alkanes. The importance of directing group assistance and C? H functionalization using CO surrogates is also included. The budding development in the area of transition metal‐catalyzed C(sp3)? H activation makes us feel it necessary to file a summary on the past, as well as current, contributions and a prospective outlook on the transition metal‐catalyzed carbonylative transformation of C? H bonds, which is the focus of this review. 相似文献
3.
Dr. Dajian Zhu Dr. Guoqiang Yang Jian He Ling Chu Dr. Gang Chen Dr. Wei Gong Dr. Ke Chen Dr. Martin D. Eastgate Prof. Dr. Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2015,54(8):2497-2500
2,4,6‐Trimethoxypyridine is identified as an efficient ligand for promoting a Pd‐catalyzed ortho‐C? H amination of both benzamides and triflyl‐protected benzylamines. This finding provides guidance for the development of ligands that can improve or enable PdII‐catalyzed C? H activation reactions directed by weakly coordinating functional groups. 相似文献
4.
M. Sc. Keshav Raghuvanshi Karsten Rauch Prof. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1790-1794
Intermolecular C?H acyloxylations of phenols with removable directing groups were accomplished with a versatile ruthenium catalyst. Specifically, a cationic ruthenium(II) complex, formed in situ, enabled the chemoselective C?H oxygenations of a broad range of substrates. The catalyst proved tolerant of synthetically valuable functional groups, and the substrate scope included both (hetero)aromatic and, the more challenging, aliphatic carboxylic acids. The proposed reaction mechanism involves a reversible C?H ruthenation and an oxidatively induced C?O‐bond‐forming reductive elimination. 相似文献
5.
Mechanistic Study on Rh‐Catalyzed Stereoselective CC/CH Activation of tert‐Cyclobutanols 下载免费PDF全文
Dr. Haizhu Yu Dr. Chen Wang Yimeng Yang Prof. Zhi‐Min Dang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3839-3848
A mechanistic study was performed on the Rh‐catalyzed stereoselective C?C/C?H activation of tert‐cyclobutanols. The present study corroborated the previous proposal that the reaction occurs by metalation, β‐C elimination, 1,4‐Rh transfer, C?O insertion, and a final catalyst‐regeneration step. The rate‐determining step was found to be the 1,4‐Rh transfer step, whereas the stereoselectivity‐determining step did not correspond to any of the aforementioned steps. It was found that both the thermodynamic stability of the product of the β‐C elimination and the kinetic feasibility of the 1,4‐Rh transfer and C?O insertion steps made important contributions. In other words, three steps (i.e., β‐C elimination, 1,4‐Rh transfer, and C?O insertion) were found to be important in determining the configurations of the two quaternary stereocenters. 相似文献
6.
Palladium‐Catalyzed Construction of Heteroatom‐Containing π‐Conjugated Systems by Intramolecular Oxidative CH/CH Coupling Reaction 下载免费PDF全文
Kenta Saito Dr. Prasanna Kumara Chikkade Prof. Dr. Motomu Kanai Prof. Dr. Yoichiro Kuninobu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(23):8365-8368
Synthesis of heteroatom‐containing ladder‐type π‐conjugated molecules was successfully achieved via a palladium‐catalyzed intramolecular oxidative C?H/C?H cross‐coupling reaction. This reaction provides a variety of π‐conjugated molecules bearing heteroatoms, such as nitrogen, oxygen, phosphorus, and sulfur atoms, and a carbonyl group. The π‐conjugated molecules were synthesized efficiently, even in gram scale, and larger π‐conjugated molecules were also obtained by a double C?H/C?H cross‐coupling reaction and successive oxidative cycloaromatization. 相似文献
7.
Dr. Brian N. Laforteza Kelvin S. L. Chan Prof. Dr. Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2015,54(38):11143-11146
The commonly used para‐nitrobenzenesulfonyl (nosyl) protecting group is employed to direct the C? H activation of amines for the first time. An enantioselective ortho‐C? H cross‐coupling between nosyl‐protected diarylmethylamines and arylboronic acid pinacol esters has been achieved utilizing chiral mono‐N‐protected amino acid (MPAA) ligands as a promoter. 相似文献
8.
Diaryliodoniums by Rhodium(III)‐Catalyzed CH Activation: Mild Synthesis and Diversified Functionalizations 下载免费PDF全文
Dr. Fang Xie Zhipeng Zhang Dr. Xinzhang Yu Guodong Tang Prof. Dr. Xingwei Li 《Angewandte Chemie (International ed. in English)》2015,54(25):7405-7409
Diaryliodonium salts play an increasingly important role as an aryl source. Reported is the first synthesis of diaryliodoniums by rhodium(III)‐catalyzed C? H hyperiodination of electron‐poor arenes under chelation assistance. This C? I coupling reaction occurred at room temperature with high regio‐selectivity and functional‐group compatibility. Subsequent diversified nucleophilic functionalization of a diaryliodonium allowed facile construction of C? C, C? N, C? O, C? S, C? P and C? Br bonds, and in all cases the initial functionalization occurred at the arene containing the chelating‐group. 相似文献
9.
Unexpected Cyclization of Tritylamines Promoted by Copper Salt through CH and CN Bond Cleavages to Produce Acridine Derivatives 下载免费PDF全文
Ryosuke Morioka Dr. Koji Hirano Prof. Dr. Tetsuya Satoh Prof. Dr. Masahiro Miura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12720-12724
Herein, we demonstrate that tritylamines undergo an unprecedented copper‐mediated cyclization involving the cleavages of two C?H bonds and one C?N bond to give 9‐arylacridine derivatives. This kind of acridines is of interest due to their biological properties and their unique optical and electro‐ and photochemical properties. Some of obtained acridine derivatives exhibit intense fluorescence in the solid state. 相似文献
10.
M. Sc. Fanzhi Yang Karsten Rauch M. Sc. Katharina Kettelhoit Prof. Dr. Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2014,53(42):11285-11288
Versatile ruthenium(II) complexes allow for site‐selective C? H oxygenations with weakly‐coordinating aldehydes. The challenging C? H functionalizations proceed with high chemoselectivity by rate‐determining C? H metalation. The new method features an ample substrate scope, which sets the stage for the step‐economical preparation of various bioactive heterocycles. 相似文献
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Dr. Yaxi Yang Dr. Wei Hou Lihuai Qin Dr. Juanjuan Du Huijin Feng Dr. Bing Zhou Dr. Yuanchao Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):416-420
The rhodium‐catalyzed intermolecular direct C?H thiolation of arenes with aryl and alkyl disulfides was developed for the first time to provide a convenient route to aryl thioethers. This strategy is compatible with many different directing groups and exhibits excellent functional group tolerance. More significantly, mono‐ or dithiolation can be selectively achieved, thus providing a straightforward way for selective preparation of aryl thioethers and dithioethers. 相似文献
13.
Copper(I)‐Catalyzed Alkylation of Polyfluoroarenes through Direct CH Bond Functionalization 下载免费PDF全文
Shuai Xu Guojiao Wu Fei Ye Xi Wang Huan Li Xia Zhao Dr. Yan Zhang Prof. Dr. Jianbo Wang 《Angewandte Chemie (International ed. in English)》2015,54(15):4669-4672
The copper(I)‐catalyzed alkylation of electron‐deficient polyfluoroarenes with N‐tosylhydrazones and diazo compounds has been developed. This reaction uses readily available starting materials and is operationally simple, thus representing a practical method for the construction of C(sp2)? C(sp3) bonds with polyfluoroarenes through direct C? H bond functionalization. Mechanistically, copper(I) carbene formation and subsequent migratory insertion are proposed as the key steps in the reaction pathway. 相似文献
14.
Ruthenium(II)‐Catalyzed Synthesis of Isochromenes by CH Activation with Weakly Coordinating Aliphatic Hydroxyl Groups 下载免费PDF全文
Sachiyo Nakanowatari Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5409-5413
Cationic ruthenium(II) complexes have been employed for the highly effective oxidative annulation of alkynes with benzyl alcohols to deliver diversely decorated isochromenes. The hydroxyl‐directed C?H/O?H functionalization process proceeded efficiently under an atmosphere of air. Detailed mechanistic studies were indicative of a kinetically relevant C?H metalation. 相似文献
15.
Amidines for Versatile Ruthenium(II)‐Catalyzed Oxidative CH Activations with Internal Alkynes and Acrylates 下载免费PDF全文
Jie Li Dr. Michael John Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5403-5408
Cationic ruthenium complexes derived from KPF6 or AgOAc enabled efficient oxidative C?H functionalizations on aryl and heteroaryl amidines. Thus, oxidative annulations of diversely decorated internal alkynes provided expedient access to 1‐aminoisoquinolines, while catalyzed C?H activations with substituted acrylates gave rise to structurally novel 1‐iminoisoindolines. The powerful ruthenium(II) catalysts displayed a remarkably high site‐, regio‐ and, chemoselectivity. Therefore, the catalytic system proved tolerant of a variety of important electrophilic functional groups. Detailed mechanistic studies provided strong support for the cationic ruthenium(II) catalysts to operate by a facile, reversible C?H activation. 相似文献
16.
Copper/Silver‐Mediated Direct ortho‐Ethynylation of Unactivated (Hetero)aryl CH Bonds with Terminal Alkyne 下载免费PDF全文
Yue‐Jin Liu Yan‐Hua Liu Xue‐Song Yin Wen‐Jia Gu Prof. Dr. Bing‐Feng Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):205-209
A copper/silver‐mediated oxidative ortho‐ethynylation of unactivated aryl C?H bonds with terminal alkyne has been developed. The reaction uses the removable PIP directing group and features broad substrate scope, high functional‐group tolerance, and compatibility with a wide range of heterocycles, providing an efficient synthesis of aryl alkynes. This procedure highlights the potential of copper catalysts to promote unique, synthetically enabling C?H functionalization reactions that lie outside of the current scope of precious metal catalysis. 相似文献
17.
Silver‐Catalyzed Oxidative Activation of Benzylic CH Bonds for the Synthesis of Difluoromethylated Arenes 下载免费PDF全文
Peng Xu Shuo Guo Liyan Wang Prof. Dr. Pingping Tang 《Angewandte Chemie (International ed. in English)》2014,53(23):5955-5958
A mild and catalytic method to form difluoromethylated arenes through the activation of benzylic C? H bonds has been developed. Utilizing AgNO3 as the catalyst, various arenes with diverse functional groups undergo activation/fluorination of benzylic C? H bonds with commercially available Selectfluor reagent as a source of fluorine in aqueous solution. The reaction is operationally simple and amenable to gram‐scale synthesis. 相似文献
18.
Catalytic Borylation of SCF3‐Functionalized Arenes by Rhodium(I) Boryl Complexes: Regioselective CH Activation at the ortho‐Position 下载免费PDF全文
Dipl.‐Chem. Sabrina I. Kalläne Prof. Dr. Thomas Braun 《Angewandte Chemie (International ed. in English)》2014,53(35):9311-9315
An unprecedented reaction pathway for the borylation of SCF3‐containing arenes using [Rh(Bpin)(PEt3)3] (pin=pinacolato) is reported. Catalytic processes were developed and the functionalizations proceed under mild reaction conditions. The C? H activations occur with a unique regioselectivity for the position ortho to the SCF3 group, which apparently serves as directing group. Borylated SCF3 compounds can serve as versatile building blocks. 相似文献
19.
Dr. Margaret L. Scheuermann David W. Boyce Prof. Kyle A. Grice Prof. Werner Kaminsky Prof. Stefan Stoll Prof. William B. Tolman Prof. Ole Swang Prof. Karen I. Goldberg 《Angewandte Chemie (International ed. in English)》2014,53(25):6492-6495
[Pd(P(Ar)(tBu)2)2] ( 1 , Ar=naphthyl) reacts with molecular oxygen to form PdII hydroxide dimers in which the naphthyl ring is cyclometalated and one equivalent of phosphine per palladium atom is released. This reaction involves the cleavage of both C? H and O? O bonds, two transformations central to catalytic aerobic oxidizations of hydrocarbons. Observations at low temperature suggest the initial formation of a superoxo complex, which then generates a peroxo complex prior to the C? H activation step. A transition state for energetically viable C? H activation across a Pd? peroxo bond was located computationally. 相似文献
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