With silicon-carbon bonds

STEREOCHEMICAL ASPECT OF SILICON COMPOUNDS AND REACTION IN THE SYNTHESIS OF POLYMERS WITH SILICON-CARBON BONDS... 

The polarity of the silicon-carbon bond will affect the manner in which the reaction with ions and molecules takes place. For example, on reaction with... 

The reaction of tetramethylsilane with fluorine led to the isolation of several, partially fluorine-substituted tetramethylsilanes (see Tables VII-IX), and preservation of over 80% of the silicon-carbon bonds in the initial, tetramethylsilane reactant. The stability of many of the partially fluorinated germanes and silanes (some are stable to over 100°C) is very surprising, for the possibility of elimination of hydrogen fluoride is obvious. Indeed, before the first reported synthesis (12) of... 

IV. Organometallic Complexes with Silicon-Carbon-Transition Metal Bonds 310... 

ORGANOMETALLIC COMPLEXES WITH SILICON-CARBON-TRANSITION METAL BONDS... 

B. The Synthesis of Compounds with Silicon-Carbon-Transition Metal (RR MeSi—C—M) Bonds... 

Reversed-phase PLC precoated plates are based on silica gel matrices with chemical modifications in such a manner that the accessible polar, hydrophilic silanol groups at the silica gel surface are replaced by nonpolar, hydrophobic alkyl chains via silicon-carbon bonds. For preparative purposes, up to now only PLC precoated RP plates with C-18 modification are available. This abbreviation is often also designated as RP-18, meaning that an octadecyl alkyl chain is chemically bonded to the silica gel surface. 

The origin of the persistent radicals which are produced in low yields is of some interest. Simple photochemical silicon-carbon bond cleavage lacks precedent and is not consistent with the failure to observe any alkane or 1-alkene in the photolysis mixture. While the latter could not be expected to survive in the irradiated solution, the former would. A possible route involving photochemical 1,1-reductive elimination is described below. 

Another application of [Bu4N][Ph3SiF2] 826 involves the silicon-carbon bond cleavage of allyl-, benzyl-, and alkynylsilane derivatives 827-829.826 Subsequent reactions of the generated carbanions with electrophiles (Scheme 112) and alkyl halides (Scheme 113) provide high yields of carbon-carbon coupled products. 

The analytical control of this step is of special importance the alcaline saponification is performed at a relatively low pH in order to prevent cleavage of the silicon-carbon bond. The closer the electron-with-drawing carboxyl group is located to the Si-C-bond, the larger is the danger of scission. Therefore, for the B-silyl carboxylic acid derivatives the pH during saponification should not surpass 10.5 however, at this pH saponification of the methyl ester requires about 1 day, even at 60°C. For the -silyl derivatives, the pH of the reaction mixture is not critical. We therefore now exclusively utilize the latter. 

Organic groups were detected on the surface after grinding of silica in the presence of organic solvents. Silicon-carbon bonds are also formed by nucleophilic attack on the siloxane bonds with lithium organic compounds. This reaction is analogous to the dissolution of silica with alkali hydroxides. 

The IR spectrum reveals a trans structure for the inuninium salt. The formation of benzoylsilane proceeds with complete retention of configuration at silicon and can be explained by both direct formation of a silicon-carbon bond (a) and formation of a silyloxycarbene (b) . However, cis elimination (a) does not appear to be favored in a trans structure Scheme 9) ... 

Therefore, surface modification strategies for the formation of direct silicon-carbon bonds require, first, a special pre-treatment of the silicon surface to prevent oxidation and, second, an activation of the silicon surface for subsequent reaction with organic moieties. This has been achieved by treatment of the silicon surface with hydrofluoric acid to generate a hydrogen-terminated Si(lll) surface, which can further react with unsaturated co-functionahzed alkenes in the presence of UV irradiation or by thermal activation [27,44,45]. Using this method, carboxylic acid modified silicon substrates have been successfully generated and coupled to thiol modified ONDs via a polylysine/sulfosuccinimidyl 4-(M-maleimidomethyl)-cyclohexane-l-carboxylate couphng (Fig. 12). 

It reacts with carbon monoxide to form a compound with a silicon carbon bond ... 

Song, J. H. and Sailor, M. J. Functionalization of nanocrystalline porous silicon surfaces with aryllithium reagents Formation of silicon-carbon bonds by cleavage of silicon-silicon bonds. Journal of the American Chemical Society 120, 2376 (1998). 

The chemistry of silacyclopentanes resembles closely that of acyclic alkylsilanes. Strong bases are needed to cleave the silicon-carbon bond, while electrophilic attack occurs readily with halogens and strong acids, e.g. sulfuric. In addition, aluminum chloride will induce polymerization of silacyclopentanes unless one of the groups on silicon is carbofunctional (Scheme 154) (67MI12000). If this is chloromethyl, then ring expansion occurs (Scheme 155). 

In 1982, Curtis and co-workers reported that Vaska s complex promotes the formation of phenylsiloxanes from the reaction of hydridosiloxanes and benzene in a catalytic, albeit low-yield, process.93 Catalytic arylsilane formation has also been reported by Tanaka and co-workers. Under photo-lytic conditions, RhCl(CO)(PMe3)2 catalyzes the C-H bond activation of arenes in reactions with hydrosilanes or disilanes, leading to the formation of new silicon-carbon bonds.94 More recently, C-H bond activation of arenes resulting in arylsilane formation has been observed in the... 

The coupling of a trialkylsilane and an amine with loss of H2, catalyzed by palladium on carbon, was first reported by Sommer and Citron in 1967.178 More recent work by Laine and Blum has involved the application of catalytic dehydrocoupling of compounds containing Si-H and N-H bonds to form aligo- and polysilazanes. These polymers, with silicon-nitrogen bonds in the backbone, are useful precursors to silicon nitride. In the presence of Ru3(CO)i2, silicon-nitrogen bonds are cleaved and reformed... 

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