Trimethylsilylmethyl derivatives

This route has, for example, been used to make the butyl compounds.15 The trimethylsilylmethyl derivatives have also been made1617 they can be precipitated from cyclohexane, washed free from organomercury starting materials, and obtained without organometal-alkoxide contaminants. Alternatively, KCH2SiMe3 may be used in situ, e.g., for metallation of alkenes.18... 

Trimethylsilylmethyl derivatives of the heavier alkali metals have been used in the synthesis of other organometallic compounds.61617,45 but so far there do not appear to be any reports of structure determinations. 

By reacting directly with the alkali metal, organomercury compounds are commonly used to synthesize organoalkali metal compounds of the heavier alkali metals. This route has been used to make various alkyl compounds, such as butyl and trimethylsilylmethyl derivatives (equation 10). 

The chloro imido-amidinato titanium complex TiGl(NBut)[PhC(NSiMe3)2](py)2 reacts with LiCH2SiMe3 or with LiCH(SiMe3)2 in benzene to give rare examples of terminal imido monoalkyltitanium derivatives TiR(NBut)[PhG(NSiMe3)2](py) (Scheme 36). The molecular structure of the trimethylsilylmethyl derivative has been determined by X-ray diffraction.90... 

For example, the trimethylsilylmethyl derivative of chromium(II) is well suited to this purpose. Although it produces a highly active catalyst on aluminophosphate or fluoride-treated alumina supports, it is barely active on silica by itself. Nevertheless, when added to silica-supported Cr(II) oxide, the result is a highly active catalyst that produces branched polymer. In addition to reacting with silanol groups, the chromium alkyl may also react with chromium oxide to again produce mono-attached species, such as is shown in Scheme 44. Coordination between one Cr atom and its chromium or oxide neighbor also seems likely. 

The trimethylsilylmethyl derivative of chromium(II) can even be added to Cr(VI) oxide catalysts, to produce hybrid or "two valent" catalysts that are considerably more active than either component alone [660,682]. Presumably, in addition to reacting with silanol groups, the organochromium component also reacts with and reduces the Cr(VI) oxide to an unknown, but highly active, state. In this way, inactive Cr(VI) oxide sites can react with the organochromium compound to produce a new active site. 

Carbonylation of the trimethylsilylmethyl derivatives 5a and 5J> provides further information on the reactivity of organoactin -ide bihaptoacyls (6,33 ). The reaction of these compounds with carbon monoxide takes place at -78° C (equation (12)). 

Several methods for making pyrroles involve in situ generation of azomethine ylides and anions. In the presence of electrophilic acetylenes these can be trapped and converted to pyrroles. One source of azomethine ylides are A -(a-trimethylsilylmethyl) derivatives of imidates and thioimidates. Azomethine ylides are generated by desilylation with fluoride ion. The salts are obtained by N-alkylation of imidate esters <83TL4303> or S-alkylation of thioacetamides <86JOCi997>. The alkoxy or alkylthio groups are eliminated after cycloaddition. Electrophilic alkenes such as dimethyl maleate, dimethyl fumarate, maleonitrile and methyl acrylate give A -pyrrolenines (Scheme 80). 

In the neopentyl-trimethylsilylmethyl derivative [(Bu CH2)(Me3SiCH2)InCl] dimeric tectons formed by dative bonding (In-Cl 2.572 and 2.659 A) are self-organized in ladder supramolecular arrays, 32, via secondary bonding (In --Cl 3.528 A) [139]. The indium atom is five-coordinate (distorted trigonal bipyramidal). 

Bis- and tris(trimethylsilyl)methyllithium can be obtained by reacting RLi with the appropriately substituted methane [113] Bis(trimethylsilylmethyl) derivatives of zinc [114] cadmium [115] and mercury [112] are all volatile liquids. The zinc and cadmium compounds are readily hydrolysed and oxidized, unlike the mercury derivative. 

It is known that REM trimethylsilylmethyl derivatives are stable and this ligand is isoelectronic to trimethylmethylenephosphorane. On diis base Schumann and coworkers have supposed that the lanthanoid complexes with phosphoric ylides ligands should be also stable and have realized their synthesis [54, 234-238, 240-243]. It was found that the direct reaction of Me3P-CH2 with REM chlorides in the pentane or hexane medium leads to the formation of insoluble pyrophoric phosphonium salts with a high yield ... 

Reaction of TMSC(Li)N2 with Halides of Boron, Phosphorus, Sulfur, and Tin. TMSC(Li)N2 undergoes the reaction with halides of boron,phosphorus, and sulfur to give the corresponding diazo trimethylsilylmethyl derivatives (eqs 36-38), while tin(II) chloride affords the carbodiimide (eq 39). ... 

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