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A completely new application of dimethyltitanocene as catalyst for the intermolecular hydroamination of alkynes is presented. With this inexpensive and readily available catalyst, alkynes can be easily converted into imines, amines, and ketones (see reaction scheme). 相似文献
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Commercially available alpha-aminodiphenylmethane 1 (benzhydrylamine) serves as a convenient ammonia equivalent in the dimethyltitanocene-catalyzed intermolecular hydroamination of alkynes. The primary formed imines can be hydrogenated and cleaved directly to the corresponding primary amines by catalytic hydrogenation using Pd/C as catalyst. 相似文献
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Soshi Nishino Prof. Dr. Koji Hirano Prof. Dr. Masahiro Miura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(40):8725-8728
A copper-catalyzed reductive gem-difunctionalization of terminal alkynes with hydrosilanes and hydroxylamines has been developed. The reaction proceeds via hydrosilylation/hydroamination cascade, and the readily available and simple terminal alkynes can be transformed into the corresponding α-aminosilanes of medicinal interest in a single operation. Additionally, the use of chiral bisphosphine ligand successfully makes the reaction enantioselective to deliver the optically active α-aminosilanes with good enantiomeric ratios. 相似文献
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Heating o-hydroxyacetophenones and anilines under solvent-free conditions afforded the corresponding aryl ketimines in good to excellent yields. 相似文献
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Hydroamination Reactions of Alkynes with ortho‐Substituted Anilines in Ball Mills: Synthesis of Benzannulated N‐Heterocycles by a Cascade Reaction 下载免费PDF全文
Maik Weiße Markus Zille Katharina Jacob Robert Schmidt Achim Stolle 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6511-6522
It was demonstrated that ortho‐substituted anilines are prone to undergo hydroamination reactions with diethyl acetylenedicarboxylate in a planetary ball mill. A sequential coupling of the intermolecular hydroamination reaction with intramolecular ring closure was utilized for the syntheses of benzooxazines, quinoxalines, and benzothiazines from readily available building blocks, that is, electrophilic alkynes and anilines with OH, NH, or SH groups in the ortho position. For the heterocycle formation, it was shown that several stress conditions were able to initiate the reaction in the solid state. Processing in a ball mill seemed to be advantageous over comminution with mortar and pestle with respect to process control. In the latter case, significant postreaction modification occurred during solid‐state analysis. Cryogenic milling proved to have an adverse effect on the molecular transformation of the reagents. 相似文献
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Anti-Markovnikov addition of anilines to aliphatic terminal alkynes proceeded using an 8-quinolinolato rhodium/phosphine catalyst system. The use of a strong organic base, 1,1,3,3,–tetramethylguanidine, in the catalyst system enabled the formation of the aldimine products. Substrates with various functional groups including polar groups such as a phenolic hydroxy group are applicable to the hydroamination. 相似文献
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Xiaoming Zeng Guido D. Frey Dr. Shazia Kousar Guy Bertrand Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(13):3056-3060
Two very distinct chemical reactions, yet a single catalyst : A gold complex promotes the formation of tertiary enamines from a variety of terminal and internal alkynes. Subsequent addition of a terminal alkyne to the reaction mixture affords allenes (see scheme).
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Stoichiometric and Catalytic Inter‐ and Intramolecular Hydroamination of Terminal Alkynes by Frustrated Lewis Pairs 下载免费PDF全文
Tayseer Mahdi Prof. Dr. Douglas W. Stephan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11134-11142
Frustrated Lewis pairs (FLPs) based on sterically encumbered anilines and the Lewis acid B(C6F5)3 were found to react with terminal alkynes effecting intermolecular hydroamination affording iminium alkynylborate species of the form [RPhN?C(R′)Me][R′CCB(C6F5)3]. In these cases, the reagent ratio of borane, aniline, and alkyne is 1:1:2. These reactions could also be performed in an intramolecular fashion by using anilines with alkynyl substituents effecting cyclization reactions. The use of 10 mol % B(C6F5)3 under a H2 atmosphere provides a one‐pot synthesis of the pyrrolidine 12 , the piperidines 13 – 15 , the azepane 16 , the isoindoline 17 , and the benzoxazine 18 . 相似文献
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Regioconvergent and Enantioselective Rhodium‐Catalyzed Hydroamination of Internal and Terminal Alkynes: A Highly Flexible Access to Chiral Pyrazoles 下载免费PDF全文
Alexander M. Haydl Lukas J. Hilpert Prof. Dr. Bernhard Breit 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6547-6551
The rhodium‐catalyzed asymmetric N‐selective coupling of pyrazole derivatives with internal and terminal alkynes features an utmost chemo‐, regio‐, and enantioselective access to enantiopure allylic pyrazoles, readily available for incorporation in small‐molecule pharmaceuticals. This methodology is distinguished by a broad substrate scope, resulting in a remarkable compatability with a variety of different functional groups. It furthermore exhibits an intriguing case of regio‐, position‐, and enantioselectivity in just one step, underscoring the sole synthesis of just one out of up to six possible products in a highly flexible approach to allylated pyrazoles by emanating from various internal and terminal alkynes. 相似文献
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Zhong‐Ming Sun Dr. Shuo‐Ping Chen Pinjing Zhao Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(8):2619-2627
A convenient and waste‐free synthesis of indene‐based tertiary carbinamines by rhodium‐catalyzed imine/alkyne [3+2] annulation is described. Under the optimized conditions of 0.5–2.5 mol % [{(cod)Rh(OH)}2] (cod=1,5‐cyclooctadiene) catalyst, 1,3‐bis(diphenylphosphanyl)propane (DPPP) ligand, in toluene at 120 °C, N‐unsubstituted aromatic ketimines and internal alkynes were coupled in a 1:1 ratio to form tertiary 1H‐inden‐1‐amines in good yields and with high selectivities over isoquinoline products. A plausible catalytic cycle involves sequential imine‐directed aromatic C? H bond activation, alkyne insertion, and a rare example of intramolecular ketimine insertion into a RhI–alkenyl linkage. 相似文献
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Oxidation-sensitive N,N-diaryl dithiocarbamates (DTCs) are synthesized in good yields by the generation of metal amide salts from N-benzoyl precursors, followed by addition of CS2. para-Substituted diphenylamines are prepared by electrophilic aromatic substitution of diphenylbenzamide and saponification. Deacylation of electron-rich species such as bis(p-dimethylaminophenyl)benzamide is challenging because of the oxidative sensitivity of the anionic intermediate but could be achieved in good yield by using n-BuLi to generate a hemiaminal adduct, prior to acidification. The N,N-diaryl DTCs are stable as alkali salts and can be used to produce densely packed monolayers on gold surfaces. 相似文献
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We present here a facile and practical procedure for the synthesis of tetrasubstituted furans from alkynes catalyzed by palladium acetate together with cupric acetate in acetic acid, using atmospheric oxygen as a terminal oxidant. Various internal aromatic alkynes afforded the target furans in satisfactory yield. 相似文献
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Duncan AN Widenhoefer RA 《Synlett : accounts and rapid communications in synthetic organic chemistry》2010,2010(3):419-422
A mixture of (3)AuCl [3 = P(t-Bu)(2)o-biphenyl] and AgOTf catalyzes the intermolecular hydroamination of monosubstituted and 1,1- and 1,3-disubstituted allenes with primary and secondary arylamines. 相似文献