- Ligand-promoted oxidative cross-coupling of aryl boronic acids and aryl silanes by palladium catalysis
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The first cross-coupling reaction between aryl silanes and aryl boronic acids is described. This transformation represents one of the very few examples of coupling reactions between two nucleophilic organometallic reagents and provides a new method for the formation of biaryl compounds. The successful development of this reaction was enabled by the use of commercially available 2,2-bis(diphenylphosphino)-1,1-binaphthyl (BINAP) as the ligand. A small amount of BINAP (3 mol %) was sufficient to suppress the formation of the homocoupling products, and the reaction yielded the cross-coupling products with high selectivity under mild conditions, even when the ratio of the two coupling partners was 1:1.
- Yu, Jingxun,Liu, Jun,Shi, Guangfa,Shao, Changdong,Zhang, Yanghui
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supporting information
p. 4079 - 4082
(2015/03/30)
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- Synthesis of aryltriethoxysilanes via rhodium(I)-catalyzed cross-coupling of aryl electrophiles with triethoxysilane
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The general and efficient silylation of aryl halides has been developed utilizing triethoxysilane and a rhodium catalyst. The substrate scope is broad and includes ortho-, meta-, and para-substituted electron-rich and -deficient aryl iodides. In addition, the silylation of aryl bromides and fluoroalkanesulfonates proceeded in the presence of tetra-n-butylammonium iodide.
- Murata, Miki,Yamasaki, Hiyoruki,Ueta, Tsukasa,Nagata, Masayuki,Ishikura, Masanori,Watanabe, Shinji,Masuda, Yuzuru
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p. 4087 - 4094
(2008/01/03)
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- Application of directed orthometalation toward the synthesis of aryl siloxanes
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A selection of ortho-substituted aryl siloxanes have been prepared by directed orthometalation protocols. These siloxanes can be prepared in high yields and purity by use of a diverse selection of ortho-directing groups and electrophilic siloxane derivatives. The siloxanes are employed in palladium-catalyzed cross-coupling reactions with aryl bromides to generate unsymmetrical orthosubstituted biaryls in good to excellent yields.
- Seganish, W. Michael,DeShong, Philip
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p. 6790 - 6795
(2007/10/03)
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- Improved synthesis of aryltrialkoxysilanes via treatment of aryl Grignard or lithium reagents with tetraalkyl orthosilicates
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General reaction conditions for the synthesis of aryl(trialkoxy)silanes from aryl Grignard and lithium reagents and tetraalkyl orthosilicates (Si(OR)4) have been developed. Ortho-, meta-, and para-substituted bromoarenes underwent efficient metalation and silylation at low temperature to provide aryl siloxanes. Mixed results were obtained with heteroaromatic substrates: 3-bromothiophene, 3-bromo-4-methoxypyridine, 5-bromoindole, and N-methyl-5-bromoindole underwent silylation in good yield, whereas a low yield of siloxane was obtained from 2-bromofuran, and 2-bromopyridine failed to give silylated product. The synthesis of siloxanes via organolithium and magnesium reagents was limited by the formation of di- and triarylated silanes (Ar 2Si(OR)2 and Ar3SiOR, respectively) and dehalogenated (Ar-H) byproducts. Silylation at low temperature gave predominantly monoaryl siloxanes, without requiring a large excess of the electrophile. Optimal reaction conditions for the synthesis of siloxanes from aryl Grignard reagents entailed addition of arylmagnesium reagents to 3 equiv of tetraethyl- or tetramethyl orthosilicate at -30 °C in THF. Aryllithium species were silylated using 1.5 equiv of tetraethyl- or tetramethyl orthosilicate at -78 °C in ether.
- Manoso, Amy S.,Ahn, Chuljin,Soheili, Arash,Handy, Christopher J.,Correia, Reuben,Seganish, W. Michael,DeShong, Philip
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p. 8305 - 8314
(2007/10/03)
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- Rhodium(I)-Catalyzed Silylation of Aryl Halides with Triethoxysilane: Practical Synthetic Route to Aryltriethoxysilanes
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(Equation Presented) The specific silylation of aryl iodides and bromides with triethoxysilane (EtO)3SiH in the presence of NEt3 and a catalytic amount of [Rh-(cod)(MeCN)2]BF4 provides the corresponding aryltriethoxysilanes in high yield.
- Murata, Miki,Ishikura, Masanori,Nagata, Masayuki,Watanabe, Shinji,Masuda, Yuzuru
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p. 1843 - 1845
(2007/10/03)
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- Improved synthesis of aryltriethoxysilanes via palladium(O)-catalyzed silylation of aryl iodides and bromides with triethoxysilane
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The scope of the palladium-catalyzed silylation of aryl halides with triethoxysilane has been expanded to include aryl bromides. A more general Pd(0) catalyst/ligand system has been developed that activates bromides and iodides: palladium(O) dibenzylideneacetone (Pd(dba)2) is activated with 2-(di-tert-butylphosphino)biphenyl (Buchwald's ligand) (1:2 mol ratio of Pd/phosphine). Electronrich para- and meta-substituted aryl halides (including unprotected aniline and phenol derivatives) undergo silylation to form the corresponding aryltriethoxysilane in fair to excellent yield; however, ortho-substituted aryl halides failed to be silylated.
- Manoso,DeShong
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p. 7449 - 7455
(2007/10/03)
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