共查询到20条相似文献,搜索用时 15 毫秒
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Dr. Yoichi M. A. Yamada Toshihiro Watanabe Tomohiko Beppu Naoshi Fukuyama Kaoru Torii Prof. Dr. Yasuhiro Uozumi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(37):11311-11319
Instantaneous catalytic carbon–carbon bond‐forming reactions were achieved in catalytic membrane‐installed microchannel devices that have a polymeric palladium‐complex membrane. The catalytic membrane‐installed microchannel devices were provided inside the microchannels by means of coordinative and ionic molecular convolution at the interface between the organic and aqueous phases flowing laminarly, in which both non‐crosslinked linear polymer ligands and palladium species dissolved. The palladium‐catalyzed Suzuki–Miyaura reaction of aryl, heteroaryl, and alkenyl halides with arylboronic acids and sodium tetraarylborates was performed with the catalytic membrane‐installed microchannel devices to give quantitative yields of biaryls, heterobiaryls, and aryl alkenes within 5 s of residence time in the defined channel region. These microchannel devices were applied to the instantaneous allylic arylation reaction of allylic esters with arylboron reagents under microflow conditions to afford the corresponding coupling products within 1 s of residence time. 相似文献
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Imidazolium salts bearing triazole groups are synthesized via a copper catalyzed click reaction, and the silver, palladium, and platinum complexes of their N‐heterocyclic carbenes are studied. [Ag4(L1)4](PF6)4, [Pd(L1)Cl](PF6), [Pt(L1)Cl](PF6) (L1=3‐((1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)methyl)‐1‐(pyrimidin‐2‐yl)‐1H‐imidazolylidene), [Pd2(L2)2Cl2](PF6)2, and [Pd(L2)2](PF6)2 (L2=1‐butyl‐3‐((1‐(pyridin‐2‐yl)‐1H‐1,2,3‐triazol‐4‐yl)methyl)imidazolylidene) have been synthesized and fully characterized by NMR, elemental analysis, and X‐ray crystallography. The silver complex [Ag4(L1)4](PF6)4 consists of a Ag4 zigzag chain. The complexes [Pd(L1)Cl](PF6) and [Pt(L1)Cl](PF6), containing a nonsymmetrical NCN ′ pincer ligand, are square planar with a chloride trans to the carbene donor. [Pd2(L2)2Cl2](PF6)2 consists of two palladium centers with CN2Cl coordination mode, whereas the palladium in [Pd(L2)2](PF6)2 is surrounded by two carbene and two triazole groups with two uncoordinated pyridines. The palladium compounds are highly active for Suzuki–Miyaura cross coupling reactions of aryl bromides and 1,1‐dibromo‐1‐alkenes in neat water under an air atmosphere. 相似文献
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Speciation Control During Suzuki–Miyaura Cross‐Coupling of Haloaryl and Haloalkenyl MIDA Boronic Esters 下载免费PDF全文
James W. B. Fyfe Elena Valverde Ciaran P. Seath Dr. Alan R. Kennedy Dr. Joanna M. Redmond Dr. Niall A. Anderson Dr. Allan J. B. Watson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(24):8951-8964
Boronic acid solution speciation can be controlled during the Suzuki–Miyaura cross‐coupling of haloaryl N‐methyliminodiacetic acid (MIDA) boronic esters to enable the formal homologation of boronic acid derivatives. The reaction is contingent upon control of the basic biphase and is thermodynamically driven: temperature control provides highly chemoselective access to either BMIDA adducts at room temperature or boronic acid pinacol ester (BPin) products at elevated temperature. Control experiments and solubility analyses have provided some insight into the mechanistic operation of the formal homologation process. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(5):1269-1273
Chemoselective Suzuki–Miyaura cross‐coupling generally requires a designed deactivation of one nucleophile towards transmetallation. Here we show that boronic acids can be chemoselectively reacted in the presence of ostensibly equivalently reactive boronic acid pinacol (BPin) esters by kinetic discrimination during transmetallation. Simultaneous electrophile control allows sequential chemoselective cross‐couplings in a single operation in the absence of protecting groups. 相似文献
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Yasuhiro Uozumi Prof. Dr. Yutaka Matsuura Dr. Takayasu Arakawa Dr. Yoichi M. A. Yamada Dr. 《Angewandte Chemie (International ed. in English)》2009,48(15):2708-2710
You oughta use water : Broad functional‐group (FG) tolerance was observed for the title coupling of aryl halides (X=Cl, Br, I) and aryl boronic acids to give biaryl compounds with up to 94 % ee. The chiral imidazoindole phosphine–palladium catalyst supported on an amphiphilic polystyrene–poly(ethylene glycol) (PS–PEG) resin could be recycled readily.
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Dr. Sachin Handa Eric D. Slack Prof. Bruce H. Lipshutz 《Angewandte Chemie (International ed. in English)》2015,54(41):11994-11998
Nickel nanoparticles, formed in situ and used in combination with micellar catalysis, catalyze Suzuki–Miyaura cross‐couplings in water under very mild reaction conditions. 相似文献
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《化学:亚洲杂志》2017,12(14):1765-1772
The Ni‐catalyzed Suzuki–Miyaura coupling of N ‐tert‐butoxycarbonyl (N ‐Boc)‐protected amides provides a versatile strategy for the construction of C−C bonds. In this study, density functional theory (DFT) methods have been used to elucidate the mechanism of this reaction, with particular emphasis on the roles of N ‐Boc, K3PO4 and H2O. Our results corroborated those of previous reports, indicating that the overall catalytic cycle consists of three steps, including oxidative addition, transmetalation, and reductive elimination. Three of the possible transmetalation mechanisms were examined to interpret the effects of K3PO4 and H2O. According to the most feasible of these transmetalation mechanisms, K3PO4 (acting as a Lewis base) would initially interact with the Lewis acid PhBpin to give a K3PO4‐PhBpin complex, which would readily undergo a hydrogen transfer step with H2O. The H transfer in the transmetalation step was determined to be the rate‐determining step. Notably, the theoretical results showed good agreement with the experimental data. 相似文献
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本文报道了温和及有效的氯化钯多相催化无配体Suzuki-Miyaura反应,反应在室温、敞口容器和短时间内完成。各种碘代芳烃、溴代芳烃和活泼的氯代芳烃与四苯硼钠和芳香有机硼酸偶联高产率生成相应的产物,而且催化剂可循环使用4次不降低活性。 相似文献
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Tandem Chemoselective Suzuki–Miyaura Cross‐Coupling Enabled by Nucleophile Speciation Control 下载免费PDF全文
Ciaran P. Seath James W. B. Fyfe John J. Molloy Dr. Allan J. B. Watson 《Angewandte Chemie (International ed. in English)》2015,54(34):9976-9979
Control of boronic acid speciation is presented as a strategy to achieve nucleophile chemoselectivity in the Suzuki–Miyaura reaction. Combined with simultaneous control of oxidative addition and transmetalation, this enables chemoselective formation of two C? C bonds in a single operation, providing a method for the rapid preparation of highly functionalized carbogenic frameworks. 相似文献
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Mamoru Tobisu Dr. Naoto Chatani Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(20):3565-3568
Seeing the sites : The Suzuki–Miyaura reaction of substrates containing multiple coupling sites has been performed in a directed manner through the reactivity modulation of the boron moiety (see scheme). Several other strategies are also discussed.
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A new porous organic polymer (POP) with high thermal stability and large surface area has been synthesized and applied in the preparation of Pd/POP catalyst. Pd/POP was characterized by XRD, TGA, SEM and TEM. The catalyst consists of highly dispersed palladium nanoparticles of 0.9–4 nm size on POP with a large surface area of 650 m2/g. It presents high catalytic activity for Suzuki‐Miyaura and Sonogashira reactions. The catalyst was reusable for three to five times without significant loss of activity. 相似文献
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Dr. Jie Wang Dr. Tian Qin Dr. Tie‐Gen Chen Dr. Laurin Wimmer Jacob T. Edwards Dr. Josep Cornella Benjamin Vokits Dr. Scott A. Shaw Prof. Phil S. Baran 《Angewandte Chemie (International ed. in English)》2016,55(33):9676-9679
A transformation analogous in simplicity and functional group tolerance to the venerable Suzuki cross‐coupling between alkyl‐carboxylic acids and boronic acids is described. This Ni‐catalyzed reaction relies upon the activation of alkyl carboxylic acids as their redox‐active ester derivatives, specifically N‐hydroxy‐tetrachlorophthalimide (TCNHPI), and proceeds in a practical and scalable fashion. The inexpensive nature of the reaction components (NiCl2?6 H2O—$9.5 mol?1, Et3N) coupled to the virtually unlimited commercial catalog of available starting materials bodes well for its rapid adoption. 相似文献