- Potassium Alkylpentafluorosilicates, Primary Alkyl Radical Precursors in the C-1 Alkylation of Tetrahydroisoquinolines
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In this study, we demonstrate that potassium alkylpentafluorosilicates (RSiF5K2) are efficient primary alkyl radical precursors for selective C(sp3)-C(sp3) bond-forming reactions. RSiF5K2 reagents are white, free-flowing solids and are moisture and air stable. This class of reagents enables the direct C-1 alkylation of tetrahydroisoquinolines under mild conditions via single-electron transfer. The broad substrate scope of both alkylpentafluorosilicates and tetrahydroisoquinolines is tolerated in this transformation. Both radical scavenger and EPR capture experiments show that the primary radical is generated by the oxidation of RSiF5K2. A mechanism involving alkyl radical addition to an iminium salt followed by reduction by an amine is proposed.
- Wang, Teng,Wang, Dong-Hui
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supporting information
p. 3981 - 3985
(2019/06/14)
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- Radical addition of silanes to alkenes followed by oxidation
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Phenyldimethylsilane and trichlorosilane are shown to undergo efficient radical hydrosilylation reactions, on reaction with various alkenes, using triethylborane as the initiator. Adducts from the trichlorosilane reactions can be oxidised to afford alcohols in good yields. This two-step process leads to the anti-Markovnikov hydration of alkenes. Georg Thieme Verlag Stuttgart · New York.
- Palframan, Matthew J.,Parsons, Andrew F.,Johnson, Paul
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experimental part
p. 2811 - 2814
(2012/01/06)
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- Trichlorosilyl groups containing organochlorosilanes and their preparation methods by the double-silylation of olefins with trichlorosilane
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The present invention provides organosilicon compounds containing two trichlorosilyl groups and their preparation methods. Organosilicon compounds of formula II are prepared by reacting linear chain or cyclic olefins of formula I with trichlorosilane in the presence of quaternary organophosphonium salt as a catalyst.R1—HC=CH—R2??(I) 1In formulas I and II, R1 and R2 may be identical or different and represent a hydrogen atom, a linear or a cyclic C1-C8 alkyl, a linear or a cyclic C1-C8 alkenyl, benzyl, phenyl, a C1-C8 alkyl substituted phenyl group, two functional groups between R1 and R2 may be covalently bonded to form a C4-C8 ring with or without a carbon-carbon double bond.
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- Effect of the substituents at the silicon of (ω-chloroalkyl)silanes on the alkylation to benzene
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(ω-Chloroalkyl)silanes [Cl3-mMemSi(CH2)n-Cl: m=0-3, n=1-3] underwent Friedel-Crafts alkylation with benzene in the presence of aluminum chloride to give alkylated products. Such alkylation reactions took place at temperatures ranging from room temperature (m=0-1, n=2, 3; m=3, n=1) to 80 (m=1, 2; n=1) and 200°C (m=0; n=1), depending on the substituent(s) of the silicon and the alkylene-chain spacer between the silicon and C-Cl bond of (ω-chloroalkyl)silanes. In the alkylation to benzene, the reactivities of (ω-chloroalkyl)silanes increase as the number (m) of methyl-group(s) at the silicon and the alkylene length between the silicon and C-Cl bond increases. While decomposition of alkylation products was observed at two more methyl groups substituted at silicon in the cases of (chloromethyl)silanes such as (chloromethyl)dimethylchlorosilane and (chloromethyl)trimethylsilane. The reaction with (chloromethyl)trimethylsilane occurred at room temperature to give trimethylchlorosilane, toluene and xylene via a decomposition reaction of the products. No (trimethylsilylmethyl)benzene was formed. In the alkylation to benzene, the reactivity of (ω-chloroalkyl)silanes decreases in the following order: m=3>2>1>0; n=3>2?1. The results are consistent with the stability of the carbocation generated by the complexation of (ω-chloroalkyl)silanes with aluminum chloride.
- Yoo, Bok Ryul,Hyun Kim, Jeong,Lee, Ho-Jin,Lee, Kang-Bong,Nam Jung, Il
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p. 239 - 245
(2007/10/03)
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