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Organomagnesium‐Catalyzed Isomerization of Terminal Alkynes to Allenes and Internal Alkynes 下载免费PDF全文
Dr. Raphaël Rochat Koji Yamamoto Michael J. Lopez Haruki Nagae Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8112-8120
Organomagnesium complexes 2 were synthesized from N,N‐dialkylamineimine ligands 1 and dibenzylmagnesium by benzylation of the imine moiety. 3‐Aryl‐1‐propynes reacted with 2 to form the corresponding tetraalkynyl complexes, which acted as catalysts for the transformation of these terminal alkynes into allenes and further to internal alkynes under mild conditions. To the best of our knowledge, this example is the first of an organomagnesium‐catalyzed isomerization of alkynes. Notably, the reactions proceeded through temporally separated autotandem catalysis, thus allowing the isolation of the allene or internal alkyne species in good yields. Mechanistic experiments suggested that the catalytically active tetraalkynyl complexes consist of a tautomeric mixture of alkynyl‐, allenyl‐, and propargylmagnesium species. 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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Zinc‐Catalyzed Dehydrogenative Cross‐Coupling of Terminal Alkynes with Aldehydes: Access to Ynones 下载免费PDF全文
Shan Tang Li Zeng Yichang Liu Prof. Aiwen Lei 《Angewandte Chemie (International ed. in English)》2015,54(52):15850-15853
Because of the lack of redox ability, zinc has seldom been used as a catalyst in dehydrogenative cross‐coupling reactions. Herein, a novel zinc‐catalyzed dehydrogenative C(sp2)? H/C(sp)? H cross‐coupling of terminal alkynes with aldehydes was developed, and provides a simple way to access ynones from readily available materials under mild reaction conditions. Good reaction selectivity can be achieved with a 1:1 ratio of terminal alkyne and aldehyde. Various terminal alkynes and aldehydes are suitable in this transformation. 相似文献
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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: New Concepts for Designing d10‐M(L)n Catalysts: d Regime,s Regime and Intrinsic Bite‐Angle Flexibility (Chem. Eur. J. 36/2014) 下载免费PDF全文
Lando P. Wolters Dr. Willem‐Jan van Zeist Prof. Dr. F. Matthias Bickelhaupt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11234-11234
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Rhodium‐Catalyzed Annulative Coupling of 3‐Phenylthiophenes with Alkynes Involving Double C‐H Bond Cleavages 下载免费PDF全文
Tomonori Iitsuka Dr. Koji Hirano Prof. Dr. Tetsuya Satoh Prof. Dr. Masahiro Miura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):385-389
Double C?H bond activation took place efficiently upon treatment of 3‐phenylthiophenes with alkynes in the presence of a rhodium catalyst and a copper salt oxidant to form the corresponding naphthothiophene derivatives. Dehydrogenative coupling with alkenes was also found to occur on the phenyl moiety rather than the thiophene ring. These reactions provide straightforward synthetic methods for π‐conjugated molecules involving a thiophene unit from readily available, simple building blocks. 相似文献
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Cover Picture: Palladium–N‐Heterocyclic Carbene (NHC)‐Catalyzed Asymmetric Synthesis of Indolines through Regiodivergent C(sp3)H Activation: Scope and DFT Study (Chem. Eur. J. 46/2014) 下载免费PDF全文
Dmitry Katayev Dr. Evgeny Larionov Dr. Masafumi Nakanishi Dr. Céline Besnard Prof. Dr. E. Peter Kündig 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):14905-14905
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Back Cover: Total Synthesis of 7‐ and 8‐Oxygenated Pyrano[3,2‐a]carbazole and Pyrano[2,3‐a]carbazole Alkaloids via Boronic Acid‐Catalyzed Annulation of the Pyran Ring (Chem. Eur. J. 28/2014) 下载免费PDF全文
Dr. Konstanze K. Julich‐Gruner Dr. Olga Kataeva Dr. Arndt W. Schmidt Prof. Dr. Hans‐Joachim Knölker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8808-8808
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Rhodium‐Catalyzed (5+1) Annulations Between 2‐Alkenylphenols and Allenes: A Practical Entry to 2,2‐Disubstituted 2H‐Chromenes 下载免费PDF全文
Noelia Casanova Andrés Seoane Prof. José L. Mascareñas Dr. Moisés Gulías 《Angewandte Chemie (International ed. in English)》2015,54(8):2374-2377
Readily available alkenylphenols react with allenes under rhodium catalysis to provide valuable 2,2‐disubstituted 2H‐chromenes. The whole process, which involves the cleavage of one C? H bond of the alkenyl moiety and the participation of the allene as a one‐carbon cycloaddition partner, can be considered a simple, versatile, and atom‐economical (5+1) heteroannulation. The reaction tolerates a broad range of substituents both in the alkenylphenol and in the allene, and most probably proceeds through a mechanism involving a rhodium‐catalyzed C? C coupling followed by two sequential pericyclic processes. 相似文献
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Back Cover: Dormant versus Evolving Aminopalladated Intermediates: Toward a Unified Mechanistic Scenario in PdII‐Catalyzed Aminations (Chem. Eur. J. 6/2014) 下载免费PDF全文
Dr. Jamshid Rajabi Mélanie M. Lorion Vu Linh Ly Dr. Frédéric Liron Dr. Julie Oble Prof. Dr. Guillaume Prestat Prof. Dr. Giovanni Poli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1768-1768
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Inside Cover: Directing/Protecting‐Group‐Free Synthesis of Tetraaryl‐Substituted Pyrazoles through Four Direct Arylations on an Unsubstituted Pyrazole Scaffold (Chem. Eur. J. 41/2015) 下载免费PDF全文
Dr. Shinichiro Fuse Taiki Morita Dr. Kohei Johmoto Dr. Hidehiro Uekusa Dr. Hiroshi Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14234-14234
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Cp*CoIII Catalyzed Site‐Selective CH Activation of Unsymmetrical O‐Acyl Oximes: Synthesis of Multisubstituted Isoquinolines from Terminal and Internal Alkynes 下载免费PDF全文
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
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Back Cover: Gold(III)‐Mediated Contraction of Benzene to Cyclopentadiene: From p‐Benziporphyrin to Gold(III) True Tetraarylcarbaporphyrin (Chem. Eur. J. 5/2014) 下载免费PDF全文
Bartosz Szyszko Kamil Kupietz Dr. Ludmiła Szterenberg Prof. Lechosław Latos‐Grażyński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(5):1460-1460
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Dr. Liene Grigorjeva Prof. Olafs Daugulis 《Angewandte Chemie (International ed. in English)》2014,53(38):10209-10212
A method for cobalt‐catalyzed, aminoquinoline‐ and picolinamide‐directed C(sp2)? H bond alkenylation by alkynes was developed. The method shows excellent functional‐group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)2?4 H2O catalyst, Mn(OAc)2 co‐catalyst, and oxygen (from air) as a terminal oxidant. 相似文献