1- trimethylsilane

Organosilanes, such as trichlorosilanes or trimethylsilanes, can establish SA monolayers on hydroxylated surfaces. Apart from their (covalent) binding to the surface these molecules can also establish a covalent intennolecular network, resulting in an enlranced mechanical stability of the films (figure C2.4.11). In 1980, work was published on the fonnation of SAMs of octadecyltrichlorosilane (OTS) 11171. Subsequently, the use of this material was extended to the fonnation of multilayers 11341. 

Fig. 5. Synthesis of goldinamine derivatives and aurodox when is trimethylsilane.

Butyroin has been prepared by reductive condensation of ethyl butyrate with sodium in xylene, or with sodium in the presence of chloro-trimethylsilane. and by reduction of 4,5-octanedlone with sodium l-benzyl-3-carbamoyl-l,4-dihydropyridine-4-sulfinate in the presence of magnesium chloride or with thiophenol in the presence of iron polyphthalocyanine as electron transfer agent.This acyloin has also been obtained by oxidation of (E)-4-octene with potassium permanganate and by reaction of... 

Trimethylsilyl trifluoromethane (trifluoromethyl trimethylsilane) [81290-20-2] M 142.2, b 54-55°, 55-55.5°, d 0.962, n 1.332. Purified by distilling from trap to trap in a vacuum of 20mm using a bath at 45° and Dry ice-Me2CO bath for the trap. The liquid in the trap is then washed with ice cold H2O (3x), the top layer is collected, dried (Na2S04), the liquid was decanted and fractionated through a helices packed column at atmospheric pressure. H, C, F, and Si NMR can be used for assessing the purity of fractions. [Tetrahedron Lett 25 2195 1984 J Org Chem 56 984 1991.]... 

Use of freshly distilled bis(silyloxy) compound is critical in many cases, especially in this example. The yield and, more particularly, the quality of the product deteriorate with the age of the sample. Traces of acid should he avoided because even as little as one drop of chloro-trimethylsilane added to the reaction mixture produces a diflferent product. The longer the reaction time in the presence of acid, the greater is the number of other products formed. 

Table 11. Multinudear Spectral Data for Fluoromethylated Malonates [72]and Fluoromethylated Trimethylsilanes [97]...

The acid cleavage of the aryl— silicon bond (desilylation), which provides a measure of the reactivity of the aromatic carbon of the bond, has been applied to 2- and 3-thienyl trimethylsilane, It was found that the 2-isomer reacted only 43.5 times faster than the 3-isomer and 5000 times faster than the phenyl compound at 50,2°C in acetic acid containing aqueous sulfuric acid. The results so far are consistent with the relative reactivities of thiophene upon detritia-tion if a linear free-energy relationship between the substituent effect in detritiation and desilylation is assumed, as the p-methyl group activates about 240 (200-300) times in detritiation with aqueous sulfuric acid and about 18 times in desilylation. A direct experimental comparison of the difference between benzene and thiophene in detritiation has not been carried out, but it may be mentioned that even in 80.7% sulfuric acid, benzene is detritiated about 600 times slower than 2-tritiothiophene. The aforementioned consideration makes it probable that under similar conditions the ratio of the rates of detritiation of thiophene and benzene is larger than in the desilylation. A still larger difference in reactivity between the 2-position of thiophene and benzene has been found for acetoxymercuration which... 

In order to test whether this high level of diastereoselectivity is due to the stereoselective formation of 35 A, or a consequence of rapid equilibration between 35 A and 35 B, both reagents were selectively prepared via the tributylstannanes 38. Treatment of either reagent with chloro-trimethylsilane led to a similar ratio of the diastereomers 36 A/36B, with the anti-diastereomer 36A predominant in both reactions. 

The zinc-mediated allylation of racemic branched a-oxoalkanoic esters proceeds with moderate stereoselectivity46, better results are obtained with (2-propenyl)trimethylsilane/titanium(IV)... 

Similar additions may be performed with the enamine 13. However, with 3-buten-2-one or methyl 2-propenoate Lewis acid catalysis is needed to activate the Michael acceptor chloro-trimethylsilane proved to be best suited for this purpose. A remarkable solvent effect is seen in these reactions. A change from THF to HMPA/toluene (1 1) results in a reversal of the absolute configuration of the product 14, presumably due to a ligand effect of HMPA235. 

For low molecular weight aliphatic acids, try TMSDEA reagent. Otherwise, use MSTFA, BSTFA, or TRI-SIL BSA (Formula P). For analysis of the keto acids, methoxime derivatives should be prepared first, followed by the preparation of the trimethylsilane (TMS) derivatives using BSTFA reagent. This results in the meth-oxime-TMS derivatives. 

Notes, (a) Similar treatment of (l-chloroethyl)trimethylsilane provided the equivalent homologous reagent. 

A solution of the trimethylsilyl enol ether of propionyl trimethylsilane (5 mmol) (Chapter 12) and benzaldehyde diethyl acetal (5 mmol) in dichloromethane (10ml) was added to a solution of BF3.OEt2 (5 mmol) in dichloromethane (5ml), cooled to —78 C. After being stirred for lh at -78°C and 2h at -30°C, the mixture was quenched with excess saturated sodium hydrogen carbonate solution, and extracted with ether. Concentration and distillation gave the product -ethoxy acylsilane, (4.6mmol, 95%). b.p. 105-106 C/2mmHg. Treatment of this alkoxy... 

Cadmium carbonate, 82 Carbodemetallation, 11 Carbometallation, 10 Carboxylic acids, 60,86 Ccrium(ni) chloride heptahydrate, 64 a-Chiral aldehyde, 112 Chiral lanthanide, 112 ff Chloro-a-lithio-a-trimethylsilanes, 21 2 Chloro-2-methylbutane, 135 4-Chloro-2-trimethylsilylamsole. 40... 

Cyclohexanone, 23,35 Cyclohexene oxide, 137 Cyclohcxyl methyl ether, 137 l-Cydohexyl-2-methylpropene, 68-9 ( )-l-Cyclohexyl-2-trimethyl ilylethene, 12 (Z)-l-Cyclohexyl-2-trimethylsilylelhene, 12 l-Cydohcxyl-2-trimethylsilylethyne, 12 (2-Cyclohexylidene-eihyl)trimethylsilane, 29 Cyclopentadec-2-ynone, 48 Cydopentadiene, 25 Cyclopentanone, 72 Cyclopentenones, 15 Cyclopropanone, 133... 

Vinylsilanes (Chapter 3) can be readily converted into a/3-epoxysilanes, normally by treatment with mcpba (/). Alternatively, a-chloro-a-lithio-a-trimethylsilanes react efficiently with aldehydes and ketones in a manner reminiscent of the Darzens reaction (2). 

Treatment of a-sulfonyl carbanion with (iodomethyl)trimethylsilane gave / -trimethylsilyl sulfones289-291. Alkylation of / -trimethylsilyl sulfones 235 gave various /Mrimethylsilyl sulfones292. The use of (iodomethyl)tributylstannane instead of (iodomethyl)trimethylsilane was shown to afford a tributylstannanyl derivative293. This compound has been used for syntheses of terminal olefins289-293. 

TiCU, SiCl4, with a disulfide (RSSR R = alkyl or aryl), ° or with methylthio-trimethylsilane (MeSSiMe3). ... 

The hypervalent iodine oxidation of (pyridylalkyl)trimethylsilanes to the corresponding alcohols and esters has been reported <96H(43)1151>. Oxidation of 2-(phenylethynyl)p5nidine with HjOj/AcOH followed by ROH/NajCOj provides 6-alkoxy-2-phenacylpyridines 42 via an intermediate iV-oxide <96H(43)1179>. 

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