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1.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7262-7266
A highly atom economical and stereoselective synthesis of tetrasubstituted α,β‐unsaturated amides was achieved by a Cp*CoIII‐catalyzed C−H alkenylation/directing group migration sequence. A carbamoyl directing group, which is typically removed after C−H functionalization, worked as an internal acylating agent and migrated onto the alkene moiety of the product. The directing group migration was realized with the Cp*CoIII catalyst, while a related Cp*RhIII catalyst did not promote the migration process. The product was further converted into two types of tricyclic compounds, one of which had fluorescent properties. 相似文献
2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(52):16777-16781
A mild, oxidant‐free, and selective Cp*CoIII‐catalyzed amidation of thioamides with robust dioxazolone amidating agents via C(sp3)−H bond activation to generate the desired amidated products is reported. The method is efficient and allows for the C−H amidation of a wide range of functionalized thioamides with aryl‐, heteroaryl‐, and alkyl‐substituted dioxazolones under the Cp*CoIII‐catalyzed conditions. The observed regioselectivity towards primary C(sp3)−H activation is supported by computational studies and the cyclometalation is proposed to proceed by means of an external carboxylate‐assisted concerted metalation/deprotonation mechanism. The reported method is a rare example of the use of a directing group other than the commonly used pyridine and quinolone classes for Cp*CoIII‐catalyzed C(sp3)−H functionalization and the first to exploit thioamides. 相似文献
3.
Cp*CoIII Catalyzed Site‐Selective CH Activation of Unsymmetrical O‐Acyl Oximes: Synthesis of Multisubstituted Isoquinolines from Terminal and Internal Alkynes
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Bo Sun Dr. Tatsuhiko Yoshino Prof. Dr. Motomu Kanai Prof. Dr. Shigeki Matsunaga 《Angewandte Chemie (International ed. in English)》2015,54(44):12968-12972
The synthesis of isoquinolines by site‐selective C? H activation of O‐acyl oximes with a Cp*CoIII catalyst is described. In the presence of this catalyst, the C? H activation of various unsymmetrically substituted O‐acyl oximes selectively occurred at the sterically less hindered site, and reactions with terminal as well as internal alkynes afforded the corresponding products in up to 98 % yield. Whereas the reactions catalyzed by the Cp*CoIII system proceeded with high site selectivity (15:1 to 20:1), use of the corresponding Cp*RhIII catalysts led to low selectivities and/or yields when unsymmetrical O‐acyl oximes and terminal alkynes were used. Deuterium labeling studies indicate a clear difference in the site selectivity of the C? H activation step under Cp*CoIII and Cp*RhIII catalysis. 相似文献
4.
Yudai Suzuki Bo Sun Dr. Ken Sakata Dr. Tatsuhiko Yoshino Prof. Dr. Shigeki Matsunaga Prof. Dr. Motomu Kanai 《Angewandte Chemie (International ed. in English)》2015,54(34):9944-9947
The unique reactivity of [Cp*CoIII] over [Cp*RhIII] was demonstrated. A cationic [Cp*CoIII] catalyst promoted direct dehydrative C? H allylation with non‐activated allyl alcohols, thus giving C2‐allylated indoles, pyrrole, and phenyl‐pyrazole in good yields, while analogous [Cp*RhIII] catalysts were not effective. The high γ‐selectivity and C2‐selectivity indicated that the reaction proceeded by directing‐group‐assisted C? H metalation. DFT calculations suggested that the γ‐selective substitution reaction proceeded by C? H metalation and insertion of a C? C double bond, with subsequent β‐hydroxide elimination. The [Cp*CoIII] catalyst favored β‐hydroxide elimination over β‐hydride elimination. 相似文献
5.
Yudai Suzuki Bo Sun Ken Sakata Tatsuhiko Yoshino Shigeki Matsunaga Motomu Kanai 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(34):10082-10085
The unique reactivity of [Cp*CoIII] over [Cp*RhIII] was demonstrated. A cationic [Cp*CoIII] catalyst promoted direct dehydrative C H allylation with non‐activated allyl alcohols, thus giving C2‐allylated indoles, pyrrole, and phenyl‐pyrazole in good yields, while analogous [Cp*RhIII] catalysts were not effective. The high γ‐selectivity and C2‐selectivity indicated that the reaction proceeded by directing‐group‐assisted C H metalation. DFT calculations suggested that the γ‐selective substitution reaction proceeded by C H metalation and insertion of a C C double bond, with subsequent β‐hydroxide elimination. The [Cp*CoIII] catalyst favored β‐hydroxide elimination over β‐hydride elimination. 相似文献
6.
Hideya Ikemoto Ryo Tanaka Dr. Ken Sakata Prof. Dr. Motomu Kanai Dr. Tatsuhiko Yoshino Prof. Dr. Shigeki Matsunaga 《Angewandte Chemie (International ed. in English)》2017,56(25):7156-7160
A highly atom economical and stereoselective synthesis of tetrasubstituted α,β-unsaturated amides was achieved by a Cp*CoIII-catalyzed C−H alkenylation/directing group migration sequence. A carbamoyl directing group, which is typically removed after C−H functionalization, worked as an internal acylating agent and migrated onto the alkene moiety of the product. The directing group migration was realized with the Cp*CoIII catalyst, while a related Cp*RhIII catalyst did not promote the migration process. The product was further converted into two types of tricyclic compounds, one of which had fluorescent properties. 相似文献
7.
Bo Sun Tatsuhiko Yoshino Motomu Kanai Shigeki Matsunaga 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(44):13160-13164
The synthesis of isoquinolines by site‐selective C H activation of O‐acyl oximes with a Cp*CoIII catalyst is described. In the presence of this catalyst, the C H activation of various unsymmetrically substituted O‐acyl oximes selectively occurred at the sterically less hindered site, and reactions with terminal as well as internal alkynes afforded the corresponding products in up to 98 % yield. Whereas the reactions catalyzed by the Cp*CoIII system proceeded with high site selectivity (15:1 to 20:1), use of the corresponding Cp*RhIII catalysts led to low selectivities and/or yields when unsymmetrical O‐acyl oximes and terminal alkynes were used. Deuterium labeling studies indicate a clear difference in the site selectivity of the C H activation step under Cp*CoIII and Cp*RhIII catalysis. 相似文献
8.
Unnatural Amino Acid Synthesis Enabled by the Regioselective Cobalt(III)‐Catalyzed Intermolecular Carboamination of Alkenes
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Andreas Lerchen Tobias Knecht Dr. Constantin G. Daniliuc Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2016,55(48):15166-15170
Herein, we report an unprecedented regioselective and entirely atom‐economic cobalt(III)‐catalyzed method for the non‐annulative, intermolecular carboamination of alkenes. The methodology enables the direct synthesis of unnatural amino acid derivatives and proceeds under redox‐neutral conditions with a completely regioselective C?C bond and C?N bond formation. Furthermore, this reaction exemplifies the inherently different mechanistic behavior of the Cp*CoIII catalyst and its Cp*RhIII counterpart, especially towards β‐H‐elimination. 相似文献
9.
Rahul K. Shukla Akshay M. Nair Salman Khan Chandra M. R. Volla 《Angewandte Chemie (International ed. in English)》2020,59(39):17042-17048
An efficient Cp*CoIII‐catalyzed C8‐dienylation of quinoline‐N‐oxides was achieved by employing allenes bearing leaving groups at the α‐position as the dienylating agents. The reaction proceeds by CoIII‐catalyzed C?H activation of quinoline‐N‐oxides and regioselective migratory insertion of the allene followed by a β‐oxy elimination, leading to overall dienylation. Site‐selective C?H activation was achieved with excellent selectivity under mild reaction conditions, and 30 mol % of a NaF additive was found to be crucial for the efficient dienylation. The methodology features high stereoselectivity, mild reaction conditions, and good functional‐group tolerance. C8‐alkenylation of quinoline‐N‐oxides was achieved in the case of allenes devoid of leaving groups as coupling partners. Furthermore, gram‐scale preparation and preliminary mechanistic experiments were carried out to gain insights into the reaction mechanism. 相似文献
10.
Nagaraju Barsu Md. Atiur Rahman Malay Sen Prof. Basker Sundararaju 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9135-9138
An efficient and external oxidant‐free, Cp*CoIII‐catalyzed C(sp3)?H bond amidation of 8‐methylquinoline, using oxazolone as an efficient amidating agent, is reported for the first time under mild conditions. The reaction is selective and tolerates a variety of functional groups. Based on previous reports and experimental results, the deprotonation pathway proceeds through an external base‐assisted concerted metalation and deprotonation process. 相似文献
11.
《Angewandte Chemie (International ed. in English)》2017,56(5):1381-1384
A combination of Cp*RhIII‐catalyzed C−H activation and Wagner–Meerwein‐type rearrangement was successfully achieved for the first time. Thus, bridged polycyclic molecules that are not readily accessible by other means were accessed under mild conditions with high efficiency (as low as 0.5 mol % Rh catalyst) in the coupling of N ‐phenoxyacetamide with 7‐azabenzonorbornadiene. 相似文献
12.
Dr. Tobias Gensch Dr. Michael J. James Toryn Dalton Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2018,57(9):2296-2306
C?H activation reactions with high catalyst turnover numbers are still very rare in the literature and 10 mol % is a common catalyst loading in this field. We offer a representative overview of efficient C?H activation catalysis to highlight this neglected aspect of catalysis development and inspire future effort towards more efficient C?H activation. Examples ranging from palladium catalysis, Cp*RhIII‐ and Cp*CoIII‐catalysis, the C?H borylation and silylation to methane C?H activation are presented. In these reactions, up to tens of thousands of catalyst turnovers have been observed. 相似文献
13.
Comparative Catalytic Activity of Group 9 [Cp*MIII] Complexes: Cobalt‐Catalyzed CH Amidation of Arenes with Dioxazolones as Amidating Reagents
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Juhyeon Park Prof. Dr. Sukbok Chang 《Angewandte Chemie (International ed. in English)》2015,54(47):14103-14107
A procedure for the [Cp*CoIII]‐catalyzed direct C? H amidation of arenes with dioxazolone has been developed. This reaction proceeds under straightforward and mild conditions with a broad range of substrates, including anilides. A comparative study on the catalytic activity of Group 9 [{Cp*MCl2}2] complexes revealed the unique efficiency of the cobalt catalyst. 相似文献
14.
Tobias Knecht Shobhan Mondal Jian‐Heng Ye Mowpriya Das Frank Glorius 《Angewandte Chemie (International ed. in English)》2019,58(21):7117-7121
Herein, we report the redox‐neutral, intermolecular, and highly branch‐selective amidation of allylic C?H bonds enabled by Cp*IrIII catalysis. A variety of readily available carboxylic acids were converted into the corresponding dioxazolones and efficiently coupled with terminal and internal olefins in high yields and selectivities. Mechanistic investigations support the formation of a nucleophilic IrIII–allyl intermediate rather than the direct insertion of an Ir–nitrenoid species into the allylic C?H bond. 相似文献
15.
HFIP‐Assisted C−H Functionalization by Cp*CoIII: Access to Key Reactive Cobaltacycles and Implication in Catalysis
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Jesús Sanjosé‐Orduna Dr. Juan Manuel Sarria Toro Dr. Mónica H. Pérez‐Temprano 《Angewandte Chemie (International ed. in English)》2018,57(35):11369-11373
Described here is a synthetic approach to access two of the most widely invoked cationic cobaltacycles in Cp*CoIII‐catalyzed C?H functionalization reactions by C?H activation. The unique stabilizing capability of MeCN was used to surmount the previously proposed reversible nature of the C?H metalation step. Moreover, it is revealed the boosting effect of 1,1,1,3,3,3‐hexafluoroisopropanol in the metalation step and in the reaction between N‐pyrimidinylindole and diphenylacetylene under catalytic conditions. 相似文献
16.
Rhodium(III)‐Catalyzed CC and CO Coupling of Quinoline N‐Oxides with Alkynes: Combination of CH Activation with O‐Atom Transfer
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Xueyun Zhang Zisong Qi Prof. Xingwei Li 《Angewandte Chemie (International ed. in English)》2014,53(40):10794-10798
[Cp*RhIII]‐catalyzed C? H activation of arenes assisted by an oxidizing N? O or N? N directing group has allowed the construction of a number of hetercycles. In contrast, a polar N? O bond is well‐known to undergo O‐atom transfer (OAT) to alkynes. Despite the liability of N? O bonds in both C? H activation and OAT, these two important areas evolved separately. In this report, [Cp*RhIII] catalysts integrate both areas in an efficient redox‐neutral coupling of quinoline N‐oxides with alkynes to afford α‐(8‐quinolyl)acetophenones. In this process the N? O bond acts as both a directing group for C? H activation and as an O‐atom donor. 相似文献
17.
Giulia Lavarda Daiki Shimizu Toms Torres Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2020,59(8):3127-3130
Peripherally metalated porphyrinoids are promising functional π‐systems displaying characteristic optical, electronic, and catalytic properties. In this work, 5‐(2‐pyridyl)‐ and 5,10,15‐tri(2‐pyridyl)‐BIII‐subporphyrins were prepared and used to produce cyclometalated subporphyrins by reactions with [Cp*IrCl2]2, which proceeded through an efficient C?H activation to give the corresponding mono‐ and tri‐IrIII complexes, respectively. While the mono‐IrIII complex was obtained as a diastereomeric mixture, a C3‐symmetric tri‐IrIII complex with the three Cp*‐units all at the concave side was predominantly obtained in a high yield of 90 %, which displays weak NIR phosphorescence even at room temperature in degassed CH2Cl2, differently from the mono‐IrIII complexes. 相似文献
18.
Cooperative Lewis Acid/Cp*CoIII Catalyzed C−H Bond Activation for the Synthesis of Isoquinolin‐3‐ones
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Dr. Ju Hyun Kim Steffen Greßies Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2016,55(18):5577-5581
A facile route toward the synthesis of isoquinolin‐3‐ones through a cooperative B(C6F5)3‐ and Cp*CoIII‐catalyzed C?H bond activation of imines with diazo compounds is presented. The inclusion of a catalytic amount of B(C6F5)3 results in a highly efficient reaction, thus enabling unstable NH imines to serve as substrates. 相似文献
19.
Unprecedented Dearomatized Spirocyclopropane in a Sequential Rhodium(III)‐Catalyzed C−H Activation and Rearrangement Reaction
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Dr. Xiaoming Wang Yingzi Li Tobias Knecht Dr. Constantin G. Daniliuc Prof. K. N. Houk Prof. Frank Glorius 《Angewandte Chemie (International ed. in English)》2018,57(19):5520-5524
An unprecedented dearomatized spirocyclopropane intermediate was discovered in a sequential Cp*RhIII‐catalyzed C?H activation and Wagner–Meerwein‐type rearrangement reaction. How the oxidative O?N bond is cleaved and the role of HOAc were uncovered in this study. Furthermore, a Cp*RhIII‐catalyzed dearomatization reaction of N‐(naphthalen‐1‐yloxy)acetamide with strained olefins was developed, affording a variety of spirocyclopropanes. 相似文献
20.
Sara Martínez de Salinas Jesús Sanjos‐Orduna Carlota Odena Sergio Barranco Jordi Benet‐Buchholz Mnica H. Prez‐Temprano 《Angewandte Chemie (International ed. in English)》2020,59(15):6239-6243
Herein, we disclose the synthesis of metallacyclic Cp*CoIII complexes containing weakly chelating functional groups. We have employed these compounds not only as an exceptional platform for accessing some of the most widely invoked transient intermediates in C?H functionalization processes but also as competent catalysts in different Cp*Co‐catalyzed transformations, including a benchmark coupling reaction. 相似文献