- Site-Selective Silylation of Arenes Mediated by Thianthrene S-Oxide
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The thianthrene S-oxide (TTSO)-mediated site-selective silylation of arenes has been realized via a thianthrenation/Pd-catalyzed silylation sequence. This method features a broad substrate scope and wide functional group tolerance under mild conditions and allows the synthesis of a set of (hetero)arylsilanes with operationally simple manipulations. The application and generality of the approach were further demonstrated by the late-stage functionalization of marketed drugs. This reaction also represents the first example of a Pd-catalyzed silylation reaction of aryl sulfonium salts.
- Wu, Yichen,Huang, Yu-Hao,Chen, Xiao-Yue,Wang, Peng
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- P-Silylation of Arenes via Organic Photoredox Catalysis: Use of p-Silylated Arenes for Exclusive o-Silylation, o-Acylation, and o-Alkylation Reactions
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Photocatalytic regiospecific p-silylation of arenes has been achieved by the coupling of in situ generated silyl radical with arene radical cation. The strategy involves reductive activation of PhSe-SiR3 and single electron transfer from the electron rich
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Pushpendra,Mondal, Pradip Kumar
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supporting information
p. 7730 - 7734
(2021/10/25)
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- Nickel-Catalyzed Decarbonylation of Acylsilanes
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Nickel-catalyzed decarbonylation of acylsilanes is developed. In sharp contrast to cross-coupling reactions of acylsilanes, in which the silyl group serves as a leaving group, the silyl group is retained in the product in this decarbonylation reaction. Although the strong binding of the dissociated CO to the nickel center frequently hinders catalyst turnover in nickel-mediated decarbonylative reactions, this reaction can be catalyzed by nickel complexes bearing a CO ligand.
- Ito, Yuri,Kodama, Takuya,Nakatani, Syun,Sakurai, Shun,Tobisu, Mamoru
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p. 7588 - 7594
(2020/06/27)
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- Dimethylformamide-stabilised palladium nanoclusters catalysed coupling reactions of aryl halides with hydrosilanes/disilanes
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N,N-Dimethylformamide-stabilised Pd nanocluster (NC) catalysed cross-coupling reactions of hydrosilane/disilane have been investigated. In this reaction, the coupling reaction proceeds without ligands with low catalyst loading. N,N-Dimethylacetamide is a crucial solvent in these reactions. The solvent effect was considered by various techniques, such as transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Pd NCs can be recycled five times under both hydrosilane and disilane reaction conditions.
- Nagata, Tatsuki,Inoue, Takeru,Lin, Xianjin,Ishimoto, Shinya,Nakamichi, Seiya,Oka, Hideo,Kondo, Ryota,Suzuki, Takeyuki,Obora, Yasushi
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p. 17425 - 17431
(2019/06/24)
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- Catalytic reduction of aryl trialkylammonium salts to aryl silanes and arenes
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A new approach for the reduction of aryl ammonium salts to arenes or aryl silanes using nickel catalysis is reported. This method displays excellent ligand-controlled selectivity based on the N-heterocyclic carbene (NHC) ligand employed. Utilizing a large NHC in non-polar solvents generates aryl silanes, while small NHCs in polar solvents promote reduction to arenes. Several classes of aryl silanes can be accessed from simple aniline building blocks, including those useful for cross-couplings, oxidations, and halogenations. The reaction conditions are mild, functional group tolerant, and provide efficient access to a variety of benzene derivatives.
- Rand, Alexander W.,Montgomery, John
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p. 5338 - 5344
(2019/05/29)
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- In Situ Generation of Silyl Anion Species through Si?B Bond Activation for the Concerted Nucleophilic Aromatic Substitution of Fluoroarenes
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In situ generated silyl anion species enable the concerted nucleophilic aromatic substitution of fluoroarenes. Model DFT calculations indicated that addition of a base to a silylborane would thermodynamically form a silyl borate complex and then kinetically release a silyl anion species through Si?B bond cleavage, and that the in situ generated silyl anion equivalent would further react with a fluoroarene through a concerted nucleophilic aromatic substitution pathway with an activation barrier of ca. 20 kcal/mol to afford the silylated product with a large energy gain. Experiments confirmed that the defluorosilylation reaction took place smoothly at room temperature simply upon mixing fluoroarenes with commercially available silylborane and NaOtBu. Radical scavenger and radical clock reaction experiments provide further evidence for the in situ generation of the silyl anion.
- Kojima, Kumiko,Nagashima, Yuki,Wang, Chao,Uchiyama, Masanobu
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p. 277 - 280
(2019/04/04)
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- Silyldefluorination of Fluoroarenes by Concerted Nucleophilic Aromatic Substitution
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The reaction of readily generated silyl lithium reagents with various aryl fluorides to provide the corresponding aryl silanes is reported. DFT calculations reveal that the nucleophilic aromatic substitution of the fluoride anion by the silyl lithium reagent proceeds through concerted ipso substitution. In contrast to the classical nucleophilic aromatic substitution, this concerted ionic silyldefluorination also occurs on more electron-rich aryl fluorides.
- Mallick, Shubhadip,Xu, Pan,Würthwein, Ernst-Ulrich,Studer, Armido
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supporting information
p. 283 - 287
(2018/12/13)
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- Formal Nucleophilic Silyl Substitution of Aryl Halides with Silyllithium Reagents via Halogenophilic Attack of Silyl Nucleophiles
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A new reaction has been developed for the formal nucleophilic silyl substitution of aryl halides with silyllithium or silylpotassium reagents. Dimethylphenylsilyllithium reacted with various aryl halides to form the corresponding arylsilanes in moderate to good yields with concomitant formation of the disilanes under the optimized reaction conditions. Mechanistic studies indicated that this silyl substitution reaction progresses through polar halogenophilic attack of silyl nucleophiles.
- Yamamoto, Eiji,Ukigai, Satoshi,Ito, Hajime
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p. 2460 - 2464
(2017/10/06)
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- Suzuki-type cross coupling between aryl halides and silylboranes for the syntheses of aryl silanes
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Herein we report Pd catalyzed Suzuki type cross coupling between aryl halides and silylboranes for the syntheses of aryl silanes. This reaction shows a general substrate scope, excellent compatibility with electrophilic functionalities and good yields.
- Guo, Huifang,Chen, Xiao,Zhao, Chunliang,He, Wei
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supporting information
p. 17410 - 17412
(2015/12/09)
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- Activator-free palladium-catalyzed silylation of aryl chlorides with silylsilatranes
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The palladium-catalyzed silylation of aryl chlorides with silylsilatranes proceeds under activator-free conditions; hence, wide functional group compatibility is displayed and boryl and siloxy groups are able to survive. Experimental and computational stu
- Yamamoto, Yutaro,Matsubara, Hiroshi,Murakami, Kei,Yorimitsu, Hideki,Osuka, Atsuhiro
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p. 219 - 224
(2015/02/05)
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- Zinc-catalyzed nucleophilic substitution reaction of chlorosilanes with organomagnesium reagents
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Zinc-catalyzed nucleophilic substitution reactions of chlo-rosilanes with organomagnesium reagents afford various tetraorganosilanes under mild reaction conditions. The reactions can be performed on large scale and allow efficient preparation of functionalized tetraorganosilanes.
- Murakami, Kei,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 1415 - 1417
(2009/06/28)
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- Copper-catalyzed arylation of chlorosilanes with grignard reagents
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Nucleophilic substitution reactions of chlorosilanes with aryl Grignard reagents take place efficiently in the presence of copper(I) iodide to afford tetraorganosilanes.
- Morita, Eiji,Murakami, Kei,Iwasaki, Masayuki,Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 1012 - 1014
(2011/02/26)
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- Silver-catalyzed transmetalation between chlorosilanes and aryl and alkenyl Grignard reagents for the synthesis of tetraorganosilanes
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(Chemical Equation Presented) The silver savior: Nucleophilic substitution reactions of chlorosilanes with aryl Grignard reagents have been developed which take place under silver catalysis to afford tetraorganosilanes (see scheme). This transformation is likely to be promoted by diarylargentate reagents that are generated in situ.
- Murakami, Kei,Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
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supporting information; experimental part
p. 5833 - 5835
(2009/03/11)
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- Generation and suppression of 3-/4-functionalized benzynes using zinc ate base (TMP-Zn-ate): New approaches to multisubstituted benzenes
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We present full details of our new methods for preparing functionalized benzynes with lithium di-alkyl(2,2,6,6-tetramethylpiperidino)zincate (R 2Zn(TMP)Li) through deprotonative zincation as a key reaction. In this system, by choosing appropriate ligands for the zincate, either regioselective zincation of functionalized haloaromatics or the generation of substituted benzynes can be controlled in good yields with excellent chemoselectivity, using the same substrate. Zincation with tBu 2Zn(TMP)Li followed by electrophilic trapping or zincation with Me2Zn(TMP)Li followed by nucleophilic or diene trapping is shown to be a powerful tool for the chemoselective preparation of 1,2,3-/1,2,4- trisubstituted benzene derivatives. These methods offer far greater generality than previous methods for the synthesis of multifunctionalized benzenes. Computational/theoretical studies of the reaction mechanism of this unique benzyne formation indicated that preferential coordination of the dialkylzinc moiety of zincate to halogen is the reason for the reduced activation energy of the elimination, that is, for the formation of the benzyne. The role of the ligands on Zn in accelerating/decelerating the elimination is also discussed.
- Uchiyama, Masanobu,Kobayashi, Yuri,Furuyama, Taniyuki,Nakamura, Shinji,Kajihara, Yumiko,Miyoshi, Tomoko,Sakamoto, Takao,Kondo, Yoshinori,Morokuma, Keiji
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p. 472 - 480
(2008/10/09)
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- Synthesis of new 7-benzofuranmethanamines as heterocyclic analogues of the squalenepoxidase-inhibitor Butenafine
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Selected title compounds (6a-f, 7a-d) were synthesized by RedAl(R)-reduction of the carboxamides 4a-f and 5a-d, easily available from the corresponding (2,3-dihydro-)7-benzofurancarboxylic acids 1a-f or 2a-d, respectively. For practical reasons, the preparation of the 2,3-dihydro-2-methyl-7-benzofuranmethanamines 6h-k with varied N-substitution by alkylation of the N-methyl-benzofuranmethanamine 6g with preformed aralkylbromides 9a-d was preferred.
- Stanetty,Koller,Purstinger,Grubner
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p. 351 - 358
(2007/10/02)
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- Amine derivatives, processes for their production and their use
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Compounds of formula I STR1 wherein R1 represents a group of formula STR2 and R2 represents hydrogen or lower alkyl, or R1 and R2 together with the carbon atom to which they are attached represent a group of for
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