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1.
Understanding the Mechanisms of Unusually Fast HH,CH,and CC Bond Reductive Eliminations from Gold(III) Complexes 下载免费PDF全文
A. Nijamudheen Sharmistha Karmakar Prof. Dr. Ayan Datta 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14650-14658
Carbon–carbon bond reductive elimination from gold(III) complexes are known to be very slow and require high temperatures. Recently, Toste and co‐workers have demonstrated extremely rapid C?C reductive elimination from cis‐[AuPPh3(4‐F‐C6H4)2Cl] even at low temperatures. We have performed DFT calculations to understand the mechanistic pathway for these novel reductive elimination reactions. Direct dynamics calculations inclusive of quantum mechanical tunneling showed significant contribution of heavy‐atom tunneling (>25 %) at the experimental reaction temperatures. In the absence of any competing side reactions, such as phosphine exchange/dissociation, the complex cis‐[Au(PPh3)2(4‐F‐C6H4)2]+ was shown to undergo ultrafast reductive elimination. Calculations also revealed very facile, concerted mechanisms for H?H, C?H, and C?C bond reductive elimination from a range of neutral and cationic gold(III) centers, except for the coupling of sp3 carbon atoms. Metal–carbon bond strengths in the transition states that originate from attractive orbital interactions control the feasibility of a concerted reductive elimination mechanism. Calculations for the formation of methane from complex cis‐[AuPPh3(H)CH3]+ predict that at ?52 °C, about 82 % of the reaction occurs by hydrogen‐atom tunneling. Tunneling leads to subtle effects on the reaction rates, such as large primary kinetic isotope effects (KIE) and a strong violation of the rule of the geometric mean of the primary and secondary KIEs. 相似文献
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Dr. Richard D. Adams Dr. Vitaly Rassolov Yuen Onn Wong 《Angewandte Chemie (International ed. in English)》2014,53(41):11006-11009
The electronically unsaturated dirhenium complex [Re2(CO)8(µ‐AuPPh3)(µ‐Ph)] ( 1 ) was obtained from the reaction of [Re2(CO)8{µ‐η2‐C(H)?C(H)nBu}(µ‐H)] with [Au(PPh3)Ph]. The bridging {AuPPh3} group was replaced by a bridging hydrido ligand to yield the unsaturated dirhenium complex [Re2(CO)8(µ‐H)(µ‐Ph)] ( 2 ) by reaction of 1 with HSnPh3. Compound 2 reductively eliminates benzene upon addition of NCMe at 25 °C. The electronic structure of 2 and the mechanism of the reductive elimination of the benzene molecule in its reaction with NCMe were investigated by DFT computational analyses. 相似文献
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Alexandre Genoux Jorge A. Gonzlez Estíbaliz Merino Cristina Nevado 《Angewandte Chemie (International ed. in English)》2020,59(41):17881-17886
A new family of phosphine‐ligated dicyanoarylgold(III) complexes has been prepared and their reactivity towards reductive elimination has been studied in detail. Both, a highly positive entropy of activation and a primary 12/13C KIE suggest a late concerted transition state while Hammett analysis and DFT calculations indicate that the process is asynchronous. As a result, a distinct mechanism involving an asynchronous concerted reductive elimination for the overall C(sp2)?C(sp)N bond forming reaction is characterized herein, for the first time, complementing previous studies reported for C(sp3)?C(sp3), C(sp2)?C(sp2), and C(sp3)?C(sp2) bond formation processes taking place on gold(III) species. 相似文献
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Inside Cover: Reversible 1,1‐Hydroboration: Boryl Insertion into a CN Bond and Competitive Elimination of HBR2 or RH (Angew. Chem. Int. Ed. 18/2015) 下载免费PDF全文
Deng‐Tao Yang Soren K. Mellerup Xiang Wang Dr. Jia‐Sheng Lu Prof. Dr. Suning Wang 《Angewandte Chemie (International ed. in English)》2015,54(18):5264-5264
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Cover Picture: Unusual Nitrile–Nitrile and Nitrile–Alkyne Coupling of FcCN and FcCCCN (Chem. Eur. J. 11/2014) 下载免费PDF全文
Lisanne Becker Frank Strehler Marcus Korb Dr. Perdita Arndt Dr. Anke Spannenberg Dr. Wolfgang Baumann Prof. Dr. Heinrich Lang Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):2969-2969
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Inside Cover: Ru‐Catalysed CH Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies (Chem. Eur. J. 14/2015) 下载免费PDF全文
Carina Sollert Karthik Devaraj Dr. Andreas Orthaber Dr. Paul J. Gates Dr. Lukasz T. Pilarski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5258-5258
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Inside Cover: Kinetic Resolution of Allyl Fluorides by Enantioselective Allylic Trifluoromethylation Based on Silicon‐Assisted CF Bond CleavageZ308071 (Angew. Chem. Int. Ed. 2/2014) 下载免费PDF全文
Takayuki Nishimine Kazunobu Fukushi Naoyuki Shibata Hiromi Taira Etsuko Tokunaga Akihito Yamano Dr. Motoo Shiro Prof. Dr. Norio Shibata 《Angewandte Chemie (International ed. in English)》2014,53(2):332-332
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Gold(I)‐Catalyzed Addition of Silylacetylenes to Acylsilanes: Synthesis of Indanones by CH Functionalization through a Gold(I) Carbenoid 下载免费PDF全文
Jairo González Dr. Javier Santamaría Prof. Dr. Alfredo Ballesteros 《Angewandte Chemie (International ed. in English)》2015,54(46):13678-13681
A gold(I)‐catalyzed synthesis of indanones from trimethylsilylacetylenes and acylsilanes is presented. The reaction is initiated through a synergistic acylsilane activation–gold acetylide formation and involves consecutive alkyne σ‐gold(I) addition, π‐activation, and 1,2‐migration of a silyl group. Studies performed on the reaction mechanism allowed to establish the nature of the silyl migrating group and invoke the participation of a gold(I) carbenoid intermediate. The reaction is completed by a gold(I) C? H functionalization step. 相似文献
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Inside Cover: Catalytic Asymmetric Functionalization of Aromatic CH Bonds by Electrophilic Trapping of Metal‐Carbene‐Induced Zwitterionic Intermediates (Angew. Chem. Int. Ed. 48/2014) 下载免费PDF全文
Shikun Jia Dr. Dong Xing Dan Zhang Prof. Dr. Wenhao Hu 《Angewandte Chemie (International ed. in English)》2014,53(48):12974-12974
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Intermolecular CH Bond Activation by a Cationic Iridium(III) Dichloride Phenanthroline Complex 下载免费PDF全文
Christopher A. Swift Dr. Scott Gronert 《Angewandte Chemie (International ed. in English)》2015,54(22):6475-6478
It is demonstrated that a cationic iridium(III) dichloride phenanthroline complex is capable of C? H activation and H/D exchange. It can cleave benzylic and unactivated secondary C? H bonds, but exhibits unique selectivity when compared to similar systems that have been studied in the condensed phase. Gas‐phase rate constants and kinetic isotope effects are reported for a variety of substrates and the analysis is supported by DFT calculations at the M06/QZVP level. 相似文献
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Inside Cover: tert‐Butyl Nitrite Mediated Regiospecific Nitration of (E)‐Azoarenes through Palladium‐Catalyzed Directed CH Activation (Chem. Eur. J. 32/2014) 下载免费PDF全文
Biju Majhi Debasish Kundu Dr. Sabir Ahammed Prof. Dr. Brindaban C. Ranu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9818-9818
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Pablo Morán‐Poladura Dr. Eduardo Rubio Prof. Dr. José M. González 《Angewandte Chemie (International ed. in English)》2015,54(10):3052-3055
The cycloisomerization reaction of 1‐(iodoethynyl)‐2‐(1‐methoxyalkyl)arenes and related 2‐alkyl‐substituted derivatives gives the corresponding 3‐iodo‐1‐substituted‐1H‐indene under the catalytic influence of IPrAuNTf2 [IPr=1,3‐bis(2,6‐diisopropyl)phenylimidazol‐2‐ylidene; NTf2=bis(trifluoromethanesulfonyl)imidate]. The reaction takes place in 1,2‐dichloroethane at 80 °C, and the addition of ttbp (2,4,6‐tri‐tert‐butylpyrimidine) is beneficial to accomplish this new transformation in high yield. The overall reaction implies initial assembly of an intermediate gold vinylidene upon alkyne activation by gold(I) and a 1,2‐iodine‐shift. Deuterium labeling and crossover experiments, the magnitude of the recorded kinetic primary isotopic effect, and the results obtained from the reaction of selected stereochemical probes strongly provide support for concerted insertion of the benzylic C? H bond into gold vinylidene as the step responsible for the formation of the new carbon–carbon bond. 相似文献
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Back Cover: Silver‐Catalyzed Coupling of Two CH Groups and One‐Pot Synthesis of Tetrasubstituted Furans,Thiophenes, and Pyrroles (Chem. Eur. J. 32/2015) 下载免费PDF全文
Shuai Mao Xue‐Qing Zhu Ya‐Ru Gao Dong‐Dong Guo Prof. Dr. Yong‐Qiang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11612-11612
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Inside Cover: Superionic Conduction in Co‐Vacant P2‐NaxCoO2 Created by Hydrogen Reductive Elimination (Chem. Asian J. 10/2016) 下载免费PDF全文
Dr. Kenichi Kato Dr. Hidetaka Kasai Dr. Akihiro Hori Prof. Dr. Masaki Takata Prof. Dr. Hiroshi Tanaka Prof. Dr. Susumu Kitagawa Akira Kobayashi Dr. Nobuki Ozawa Prof. Dr. Momoji Kubo Dr. Hidekazu Arikawa Prof. Dr. Tatsuya Takeguchi Dr. Masaaki Sadakiyo Prof. Dr. Miho Yamauchi 《化学:亚洲杂志》2016,11(10):1465-1465
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Inside Back Cover: A Gold(I)‐Catalyzed Domino Coupling of Alcohols with Allenes Enables the Synthesis of Highly Substituted Indenes (Chem. Eur. J. 41/2016) 下载免费PDF全文
Alexander Preinfalk Dr. Antonio Misale Prof. Dr. Nuno Maulide 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14755-14755