Methyl tris silane

Jeong et al. (2) prepared crosslinked copolymers consisting of methyl tri-methoxy silane and dipentaerythritol penta-/hexa-acrylate, which were effective as organic thin-film transistors and used in liquid-crystal display devices. 

Acid catalysis—hydrolysis. Several series of alkylsilane esters were studied to determine the effect of silane structure on the hydronium ion catalyzed hydrolysis reaction. The hydronium ion catalyzed hydrolysis rate constants for a series of alkyl tris-(2-methoxyethoxy)silanes in aqueous solution were used to define the modified Taft equation log(A /Ah ) = 0.39a + 1.06ES, where Ho is the rate of hydrolysis for methyl tris-2-(methoxyethoxy)silane [42], The hydronium ion catalyzed hydrolysis rate constants and the reaction half-lives are reported in Table 2. In a similar manner, the hydronium ion catalyzed hydrolysis rate constants for a series of trialkylalkoxysilanes in 55% aqueous acetone were used to obtain the modified Taft equation log(/cH//cHo) = -0.37 a + 2.48 E where kHo is the rate of hydrolysis for trimethylalkoxy-silane. 

One general method for acyl silane synthesis particularly successful for a-cyclopropyl examples (and even an a-cyclobutyl example) involves treatment of acid chlorides with lithium tetrakis(trimethylsilyl) aluminum or lithium methyl tris(trimethylsilyl) aluminium and cuprous cyanide (vide supra, Section III.A.3)77. For example, cyclopropyl acyl silane (23) was obtained in 89% yield by this process. Improved procedures use lithium t-butyldimethylsilyl cuprate78 and a dimethylphenylsilyl zinc cuprate species79,80 as reagents. 

Independently of each other, Lambert et al. [69] and Suzuki et al. [70] both gained access to low-generation silane dendrimers (Gl, G2) in 1995. The latter prepared a first-generation polysilane dendrimer 3 by a stepped growth polymerisation technique. Coupling of methyl[tris(chlorodimethylsilyl)]silane (1) to tris-(trimethylsilyl)silyllithiurn (2) led to the first-generation branched dendrimer 3 (Fig. 4.38). 

An array of 10- i,m microlenses was fabricated from the adhesion of an aminated silicasol on a poly[methyl(phenyl)silane-co-methyl(3,3,3-tri-fluoropropyl)silane] (CF3PMPS) film patterned by UV light irradiation.132 By soaking the UV-patterned polysilane film into the sol-gel solution, a convex xerogel layer adhered only to the UV-exposed poly silane, which was cured to form a glass that functioned as a condensing lens. 

Preparation of the branched silane began with the reaction of tris(trimethylsilyl)silane with CHC13 (CC14) and MeLi to afford the peralkylated methyl[tris(trimethylsilyl)]-silane. Subsequent treatment with A1C13 and ClSiMe3 gave the trichlorosilane, which was then reacted with tris(trimethylsilyl)silyllithium yielding the final silane dendrimer. 

Bell and co-workers 24, 25) have investigated the generation of tri-fluoromethyl radicals from photolysis of HFA in the presence of silanes. Abstraction of the proton is observed in the case of trichlorosilane (24), while methyl(fluoro)silanes lead to the formation of CFjH, CjF, and CF CH 2(25). 

Silan Methyl-tris-[trifluormethan-sulfonyloxy]- XIII/5, 167... 

SiC-Si3N4 Tris-n-methyl-amino-silane, silazane... 

The required bis(trimethylsilyl)methylsilyllithium (1) was prepared by splitting of methyl-tris(trimethylsilyl)silane [4] with methyllithium in tetrahydrofuran as previously described [5]. After the solvent had been changed to n-pentane, 1 was allowed to react with the appropriate chlorosilanes. As shown in Scheme 1, l,l,l,2,3,4,5,5,5-nonamethyl-2,4-bis(trimethylsilyl)-penta-silane (2) was prepared in 85 % yield directly by the slow addition of a two-fold molar excess of 1 to a solution of MeSiHCb in -pentane at -78°C. The 3-bromopentasilane (4) was obtained by bromination of 2 with tribromomethane at 120°C (yield 92 %). 

The magnesium-mediated reductive trifluoromethylation also works for other structurally diverse chlorosilanes. Chlorotriethyl-silane, f-hutyldimethylsilyl chloride, and tris(trimethylsilyl)silyl chloride have been applied to prepare corresponding trifluoro-methyl-containing silanes. However, the reductive trifluoromethylation did not take place with other electrophiles such as aldehydes, ketones, allyl bromide, benzyl chloride, or tributyltin chloride. Even tributyltin hydride and allyltrimethylsilane showed no reactivity The reason for such behavior is not clear. Probably, chlorosilanes play an important role during the reductive trifluoromethylation both as a silylating agent and a single-electron transfer promoter. 

The low ionic character of the aluminium-silicon bond has been cleverly utilized to develop a very mild, general and effective synthesis of acyl silanes, successful for aliphatic, aromatic, heteroaromatic, a-aUcoxy, a-amino and even a-chiral and a-cyclopropyl acyl sUanes. Acyl chlorides are treated with lithium tetrakis(trimethylsilyl)aluminium or lithium methyl tris(trimethylsilyl) aluminium in the presence of copper(I) cyanide as catalyst to give the acyl silanes in excellent yields after work-up. Later improvements include the use of 2-pyridinethiolesters in place of acyl halides, allowing preparation of acyl silanes in just a few minutes in very high yields indeed (Scheme 9) °, and the use of bis(dimethylphenylsilyl) copper lithium and a dimethylphenylsilyl zinc cuprate species as nucleophiles. 

Similarly, through the use of [difluoro(phenylthio)methyl]tri-methylsilane or [difluoro(phenylseleno)methyl]trimethyl-silane treated with TBAT, in the presence of amides, imines, or aldehydes, the respective difluoromethylene phenylsulfide or difluoromethylene phenylselenide is produced (eq 19). 

A Note on the Reaction of Methyl Tri-Methoxy Silane to Mixed Cultures of Microorganisms... 

A NOTE ON THE REACTICW OF METHYL TRI-METHOXY SILANE TO MIXED CULTURES OF MICRO(X GANISMS... 

Figure 3. Composite Peaks for Fourier Transform Infrared Analysis (upper) Versus Control (lower) samples of Methyl Tri-Methoxy Silane. 

As shown in Table XIV, the reactivity of (trichloromethyl)silanes varied depending upon the substituent on silicon. The reactivity and yields of (trichloromethyl)-methyldichlorosilanes were slightly higher than those of (trichloroinethyl)tri-chlorosilanes in the aluminum chloride-catalyzed alkylation as similarly observed in the alkylations with (ai-chloroalkyl)silanes and (dichloroalkyl)silanes. The electron-donating methyl group on the silicon facilitates the alkylation more than the electron-withdrawing chlorine. The minor products, (diphenylmethyl)chloro-silanes, were presumably derived from the decomposition of (triphenylmethyl)-chlorosilanes. 

Lenses with a greater degree of gas permeability were designed in the mid-1970s using siloxane-based monomers. For example, a copolymer of methyl methacrylate and the monomer known as methacryloxypropyl tris(trimethylsiloxy-silane) or TRIS (Fig. 14.6.2) was formulated in 1975 to provide a number of desir-... 

This methodology was applied to a two-step sequence for the preparation of enantio-merically enriched dihydrobenzo[h]furans (Scheme 10.11) [46]. Rhodium-catalyzed allylic etherification of (S)-47 (>99% ee), with the sodium anion of 2-iodo-6-methyl-phenol, furnished the corresponding aryl allyl ethers (S)-48/49 as a 28 1 mixture of regioisomers favoring (S)-48 (92% cee). Treatment of the aryl iodide (S)-48 with tris(trimethylsilyl)silane and triethylborane furnished the dihydrobenzo[h]furan derivatives 50a/50b as a 29 1 mixture of diastereomers [43]. 

The same research group has further performed radical carbonylation reactions on the same microreactor system [36]. First, alkyl halides were initiated and effectively reacted with pressurized carbon monoxide to form carbonyl compounds. The principle was subsequently successfully extrapolated to the multicomponent coupling reactions. 1-Iodooctane, carbon monoxide and methyl vinyl ketone were reacted in the presence of 2,2 -azobis(2,4-dimethylvaleronitrile) (V-65) as an initiator and tributyltin hydride or tris(trimethylsilyl)silane (TTMSS) as catalyst (Scheme 15). 

Optimization of the previously reported Mannich-type reaction of trimethyl (pent-2-en-3-yloxy)silane with the sulfone Is derived from phenyl acetaldehyde (Table 5, entry 11) led to the corresponding (3-amino ketone in a good yield with moderate diastereoselectivity (2 mol% Bi(0Tf)3-4H20, yield = 84%, 24v/24v syn/anti = 72 28) (Scheme 8). Reduction of the major diastereoisomer 24v with lithium tri-ferf-butoxyaluminohydride afforded 25 as the only one diastereoisomer. Further cyclization of the latter with NaH afforded 4-benzyl-6-ethyl-5-methyl-l,3-oxazinan-2-one 26. The relative configuration of the six-membered carbamate was established as cis-cis by NMR analysis. 

Bi s (tri methyl si lyloxy )cyclobut-l-ene Silane, (1 -cyclobuten-1,2-ylenedioxy)bis[trimethyl- Silane, [1-cyclobutene-1,2-diylbis(oxy)]bis[trimethy1- (17082-61-0), 65, 17 Boron trifluoride etherate Ethyl ether, compd. with boron fluoride (BFj) (1 1) Ethane, 1,1 -oxybis-, compd. with trifluoroborane (1 1) (109-63-7), 65, 17... 

O-silylierte, -acetylierle oder -benzoylierte 2-Hydroxy-carbonsaure-nitrile erhalt man ohne Katalysator und bei 20° aus aliphatischen und aromatischen Aldehyden sowie aus aliphatischcn und a, /J-ungesat-tigtcn Ketonen in einer einfach durchzufuhrenden Eintopf-Reaktion mit Lithium-cyanid und Chlor-tri-methyl-silan, Acetylchlorid oder Benzoylchlorid in THF6. 

---