- Sila-metalation route to hydrido(trialkylsilyl)silyllithiums
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The proton abstraction (sila-metalation) of trialkylsilyl-substituted dihydridosilanes with t-BuLi or LDA in THF was found to be a convenient route to the corresponding silyllithiums (RR′SiHLi; 1a, R, R′ = t-BuMe2Si; 1b, R, R′ = Me3S
- Iwamoto, Takeaki,Okita, Junichiro,Kabuto, Chizuko,Kira, Mitsuo
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- A Catalytic SEAr Approach to Dibenzosiloles Functionalized at Both Benzene Cores
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A general procedure for the catalytic preparation of dibenzosiloles functionalized at one or both benzene rings starting from readily available ortho-silylated biphenyls is reported. This method provides rapid access to silole building blocks substituted with chlorine atoms at both phenylene groups, thereby allowing catalytic access to directly polymerizable dibenzosiloles. Moreover, it is shown that, despite the involvement of highly electrophilic intermediates, a considerable range of Lewis-basic, for example, oxygen- and nitrogen-containing, functional groups is tolerated. The mechanism of this intramolecular electrophilic aromatic substitution (SEAr) proceeds through a sulfur-stabilized silicon cation, generated catalytically from the hydrosilane precursor.
- Omann, Lukas,Oestreich, Martin
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p. 10276 - 10279
(2015/09/01)
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- Intramolecular termination of radical-polar crossover reactions
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Cyclic ethers result from intramolecular trapping of cations formed through the radical-polar crossover process.
- Murphy, John A.,Rasheed, Faiza,Roome, Stephen J.,Scott, Karen A.,Lewis, Norman
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p. 2331 - 2339
(2007/10/03)
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- Preparation of New Monomeric, Oligomeric, and Polymeric Silyl Triflates
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The highly reactive silyl triflates R3SiOSO2CF3 are valuable reagents in organosilicon chemistry.New triflate derivatives of mono- and oligosilanes have been prepared by substitution of phenyl groups or hydrogen atoms for the trifluoromethanesulfonyl group.The presence of the electron-withdrawing triflate group leads to a strong deactivation of the other substituents at the silicon atom, and the displacement of a second phenyl group at the same silicon atom is much slower than the first step.For this reason in the case of phenylated oligosilanes stepwisemonosubstitution of the silicon atoms has been found.Other new oligomeric silyl triflates are obtained by reaction of silanediyl(triyl) bis(tris)(trifluoromethanesulfonates) with lithium derivatives of organosilicon compounds.Finally, the cleavage of silicon - phenyl bonds of poly by CF3SO3H leads to triflate derivatives of polysilanes. Key Words: Silyl triflates / Organosilanes
- Uhlig, Wolfram
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- Organoaluminium induced ring-opening of epoxypyranosides. V. Formal total synthesis of antimycin A3 and synthesis of (+)-blastmycinone
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Epoxide ring-opening of the benzyl 2,3-anhydro-α-L-ribopyranoside 6 with lithium butynyl(trimethyl)aluminate followed by functional group interconversions gave the dihydroxy thioacetal 11, which was regio-selectively acylated with an L-threonine derivativ
- Inghardt, Tord,Frejd, Torbjoern
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p. 6483 - 6492
(2007/10/02)
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- STEREO-CONTROLLED SYNTHESIS OF ERYTHRONOLIDES A AND B FROM 1,6-ANHYDRO-β-D-GLUCOPYRANOSE (LEVOGLUCOSAN). SKELETON ASSEMBLY IN (C9 - C13) + (C7 - C8) + (C1 - C6) SEQUENCE
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Stereospecific syntheses of erythronolides A and B have been accomplished starting from 1,6-anhydro-β-D-glucopyranose (levoglucosan) in a uniform synthetic sequence.
- Kochetkov, N. K.,Sviridov, A. F.,Ermolenko, M. S.,Yashunsky, D. V.,Borodkin, V. S.
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p. 5109 - 5136
(2007/10/02)
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- Reactivity of Hypervalent Species: Reactions of Anionic Penta-Coordinated Silicon Complexes towards Nucleophiles
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The reactivity of anionic penta-coordinated silicon complexes 4-O)2>-Na+ 1 with nucleophilic reagents has been studied. 1 can be reduced to organosilanes RSiH3 by metallic hydrides.Reactions with an excess of Grignard or organolithium reagents (R'MgX or R'Li) gave tetraorganosilanes RSiR'3.When only two molar equivalents of Grignard reagents (R'MgX) or lithium reagents (R'Li) are added to complexs 1 functional silanes RR'2SiX can be prepared.
- Boudin, Alain,Cerveau, Genevieve,Chuit, Claude,Corriu, Robert J. P.
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p. 101 - 106
(2007/10/02)
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