- Regiochemical aspects of the platinum oxide catalyzed hydrosilylation of alkynes
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The platinum-catalyzed hydrosilylation of unsymmetrical substituted arylalkynes with various hydrosilanes was investigated and the reaction selectivity of various para-substituted substrates was compared with that of their corresponding orthosubstituted derivatives. We showed that heterogeneous platinum oxide is a very efficient catalyst for such hydrosilylations and that H-Si bond addition proceeds in a stereoselective cis-fashion. The regioselectivity was found to be under the control of the ortho-substituent rather than due to the nature of the platinum catalyst. Arylalkynes with an ortho-substituent provided predominantly to exclusively α-selectivity, regardless of the electronic nature of the substituent. The precise contributions of steric, electronic, and coordinative factors controlling the regioselectivity of the H-Si bond addition are discussed. Georg Thieme Verlag Stuttgart.
- Hamze, Abdallah,Provot, Olivier,Brion, Jean-Daniel,Alami, Mouad
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- A recyclable and reusable K2PtCl4/Xphos-SO3Na/PEG-400/H2O system for highly regio- and stereoselective hydrosilylation of terminal alkynes
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K2PtCl4/Xphos-SO3Na in a mixture of poly(ethylene glycol) (PEG-400) and water is shown to be a highly regio- and stereoselective catalyst for the hydrosilylation of terminal alkynes with hydrosilanes. The reaction could be conducted under mild conditions, yielding a variety of functionalized β-(E)-vinylsilanes in good to excellent yields with a total β-(E)-selectivity. The isolation of the products is readily performed by extraction with cyclohexane and more importantly, both expensive K2PtCl4 and Xphos-SO3Na in a PEG-400/H2O system could be easily recycled and reused at least eight times without any loss of catalytic activity.
- Xu, Caifeng,Huang, Bin,Yan, Tao,Cai, Mingzhong
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supporting information
p. 391 - 397
(2018/02/07)
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- FeCl2/DTBP: An efficient and highly E-selective cross - coupling of silanes with styrene and its derivatives
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An efficient FeCl2-catalyzed cross-coupling of silanes with styrene and its derivatives using DTBP as oxidant for selective synthesis of vinylsilanes was developed. This method presented an inexpensive, non-toxic and environmentally benign cata
- Xu, Rui,Cai, Chun
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- Rhodium-catalyzed alkenylation of nitriles via silicon-assisted C-CN bond cleavage
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Rhodium-catalyzed Mizoroki-Heck type reaction of nitriles via the cleavage of C-C bonds is described. Orthogonal and iterative functionalizations of arenes were also demonstrated by combining the present and conventional halide-based cross-coupling reacti
- Kita, Yusuke,Tobisu, Mamoru,Chatani, Naoto
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supporting information; experimental part
p. 1864 - 1867
(2010/10/02)
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- Platinum chloride/Xphos-catalyzed regioselective hydrosilylation of functionalized terminal arylalkynes
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Totally regioselective hydrosilylation of functionalized terminal arylalkynes was achieved using PtCl2 associated with the air-stable and bulky Xphos ligand with various silanes. Regardless of the electronic nature of the substituents on the ar
- Hamze, Abdallah,Provot, Olivier,Brion, Jean-Daniel,Alami, Mouad
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p. 2429 - 2431
(2008/09/20)
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- Xphos ligand and platinum catalysts: A versatile catalyst for the synthesis of functionalized β-(E)-vinylsilanes from terminal alkynes
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Hydrosilylation of functionalized terminal arylalkynes with a variety of silanes catalyzed by PtCl2 or PtO2 in the presence of the air-stable and bulky Xphos ligand was investigated. Regardless of the electronic nature (electron withdrawing or donating group) and the position (o, m, p) of the substituents on the aromatic ring, a single β-(E)-styrylsilanes was obtained in good to excellent yields. The regioselectivity of the H-Si bond addition was found to be governed by steric effects induced by the bulky Xphos ligand. A dramatic regioselectivity was also observed when functionalized terminal aliphatic alkynes were employed as a substrate and in these cases regioisomeric β-(E)-vinylsilanes were generated with excellent selectivity.
- Hamze, Abdallah,Provot, Olivier,Brion, Jean-Daniel,Alami, Mouad
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p. 2789 - 2797
(2008/12/20)
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- Selective synthesis of (E)-triethyl(2-arylethenyl)silane derivatives by reaction of aryl bromides with triethyl vinylsilane catalysed by a palladium-tetraphosphine complex
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Cis, cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane / 0.5 [PdCl(C3H5)]2 system catalyses the Heck reaction of vinylsilane derivatives with a range of aryl bromides with high ratio substrate/catalyst in good yields. The formation of mixtures of styrene, (E)-triethyl(2-arylethenyl)silane and triethyl(1-arylethenyl)silane derivatives was observed in some cases. Very high selectivities (up to 100%) in favour of the formation of (E)-triethyl(2-arylethenyl)silane derivatives were obtained in the presence of sodium acetate as base. With other bases such as potassium carbonate, the formation of large amounts of styrene derivatives was observed. The reaction tolerates several functions such as fluoro, trifluoromethyl, methoxy, dimethylamino, acetyl, formyl, benzoyl, carboxylate, nitro or nitrile. Moreover, turnover numbers up to 10,000 can be obtained for this reaction.
- Battace, Ahmed,Zair, Touriya,Doucet, Henri,Santelli, Maurice
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p. 3790 - 3802
(2007/10/03)
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