- Catalytic Hydrosilylation of Hydrofluoroolefins (HFOs): Synthesis of New Fluorinated Silanes and Diversity of their Synthetic Character
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New polyfluorinated silanes were synthesized via the Pt, Rh and Pd catalyzed hydrosilylation of commercially available hydrofluoroolefins (HFOs) in moderate to excellent yields. HFO-1234yf (2,3,3,3-tetrafluoropropene-1) and –1234ze (1,3,3,3-tetrafluoropropene-1) were reactive with Pt catalyst to form tetrafluoropropylsilanes along with defluorosilylation products. The Z- and E-isomers of HFO-1336mzz (1,1,1,4,4,4-hexafluorobut-2-ene) gave the desired silanes with Pd catalysis in good to excellent yields, while with Pt catalyst only the dehydrofluorination product CF2=CHCH2CF3 (HFO-1345czf, 1,1,4,4,4-pentafluorobut-1-ene) was obtained. Synthetic applications of the new polyfluorinated silanes were illustrated by conversion of dichloro(hexafluorobutyl)(methyl)silane to the cyclic trisiloxane, which can serve as a monomer for the preparation of polysiloxanes. In addition, the hexafluorobutylsilanes showed defluorinative reactivity with lithium reagents, thereby demonstrating their synthetic utility as valuable building blocks for further transformations via C–F and C-Si bond activation.
- Pavlenko, Natalia V.,Peng, Sheng,Petrov, Viacheslav,Jackson, Andrew,Sun, Xuehui,Sprague, Lee,Yagupolskii, Yurii L.
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p. 5425 - 5435
(2020/08/14)
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- PROCESS FOR PREPARING ORGANOCHLOROSILANES BY DEHYDROHALOGENATIVE COUPLING REACTION OF ALKYL HALIDES WITH CHLOROSILANES
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The present invention relates to a process for preparing organochlorosilanes and more particularly, to the process for preparing organochlorosilanes of formula I by a dehydrohalogenative coupling of hydrochlorosilanes of formula II with organic halides of formula III in the presence of quaternary phosphonium salt as a catalyst to provide better economical matter and yield compared with conventional methods, because only catalytic amount of phosphonium chloride is required and the catalyst can be separated from the reaction mixture and recycled easily, wherein R1 represents hydrogen, chloro, or methyl; X represents chloro or bromo; R2 is selected from the group consisting of C1-17 alkyl, C1-10 fluorinated alkyl with partial or full fluorination, C2-5 alkenyl, silyl containing alkyl group represented by (CH2)nSiMe3-mClm wherein n is an integer of 0 to 2 and m is an integer of 0 to 3, aromatic group represented by Ar(R′)q wherein Ar is C6-14 aromatic hydrocarbon, R′ is C1-4 alkyl, halogen, alkoxy, or vinyl, and q is an integer of 0 to 5, haloalkyl group represented by (CH2)pX wherein p is an integer of 1 to 9 and X is chloro or bromo, and aromatic hydrocarbon represented by ArCH2X wherein Ar is C6-14 aromatic hydrocarbons and X is a chloro or bromo; R3 is hydrogen, C1-6 alkyl, aromatic group represented by Ar(R′)q wherein Ar is C6-14 aromatic hydrocarbon, R′ is C1-4 alkyl, halogen, alkoxy, or vinyl, and q is an integer of 0 to 5; and R4 in formula I is the same as R2 in formula III and further, R4 can also be (CH2)pSiR1Cl2 or ArCH2SiR1Cl2, when R2 in formula III is (CH2)pX or ArCH2X, which is formed from the coupling reaction of X—(CH2)p+1—X or XCH2ArCH2X with the compounds of formula II; or when R2 and R3 are covalently bonded to each other to form a cyclic compounds of cyclopentyl or cyclohexyl group, R3 and R4 are also covalently bonded to each other in the same fashion.
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- Process for preparing organochlorosilanes by dehydrohalogenative coupling reaction of alkyl halides with chlorosilanes
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The present invention relates to a process for preparing organochlorosilanes and more particularly, to the process for preparing organochlorosilanes of R4R3CHSiR1Cl2(I) by a dehydrohalogenative coupling of hydrochlorosilanes of HSiR1Cl2(II) with organic halides of R2R3CHX (III) in the presence of quaternary phosphonium salt as a catalyst to provide better economical matter and yield compared with conventional methods, because only a catalytic amount of phosphonium chloride is required and the catalyst can be separated from the reaction mixture and recycled easily.
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- Dehydrohalogenative coupling reaction of organic halides with silanes
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The present invention relates to methods for making the compounds of formula I which is a dehydrohalogenative coupling of hydrochlorosilanes of formula II with organic halides of formula III in the presence of a Lewis base catalyst. R3CH2SiR1Cl2??(I) HSiR1Cl2??(II) R2CH2X??(III) In formulas I and II, R1represents a hydrogen, chloro, or methyl; in formula III, X represents a chloro or bromo; in formula III, R2can be selected from the group consisting of a C1-17alkyl, a C1-10fluorinated alkyl with partial or full fluorination, a C1-5alkenyl groups, a silyl group containing alkyls, (CH2)nSiMe3-mClmwherein n is 0 to 2 and m is 0 to 3, aromatic groups, Ar(R′)1wherein Ar is C6-14aromatic hydrocarbon, R′ is a C1-4alkyl, halogen, alkoxy, or vinyl, and q is 0 to 5, a haloalkyl group, (CH2)pX wherein p is 1 to 9 and X is a chloro or bromo; or an aromatic hydrocarbon, Ar CH2X wherein Ar is C6-14aromatic hydrocarbon and X is a chloro or bromo. in formula I, R3is the same as R2in formula III and further, R3can also be (CH2)pSiR1Cl2or ArCH2SiR1Cl2when R2in formula III is (CH2)pX or ArCH2X, because of the coupling reaction of X with the compound of formula II.
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- THE REACTIONS OF HYDROSILANES WITH TRIFLUOROPROPENE AND PENTAFLUOROSTYRENE CATALYZED BY RUTHENIUM, RHODIUM AND PALLADIUM COMPLEXES
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The reactions of hydrosilanes with trifluoropropene (TFP) and pentafluorostyrene (PFS) catalyzed by Ru3(CO)12 or RhCl(PPh3)3 give β-Rf-vinylsilane (1) and/or β-Rf-ethylsilane (2) (Rf=perfluorocarbon group).The 1/2 ratio is highly dependent on the nature of hydrosilane used.The ruthenium catalyst favors the formation of 1 compared with the rhodium catalyst.Neither α-Rf-vinylsilane nor α-Rf-ethylsilane was formed at all.Possible mechanisms which can accommodate characteristic features of these reactions are discussed.The hydrosilylation of TFP with dichloromethylsilane catalyzed by PdCl2(PhCN)2/2PPh3 gives the α-adduct (9a) exclusively, and this is transformed to the corresponding dialkoxysilanes, silane diol, oligosilane diols and cyclic oligosiloxanes.
- Ojima, Iwao,Fuchikami, Takamasa,Yatabe, Momoko
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p. 335 - 346
(2007/10/02)
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