Alkyls trimethylsilyl methyl compounds

In the case of uranium, it is also possible to prepare a uranium(III) alkyl complex of the type Cp 2UR via metathesis of [Cp 2U(/tr-Cl)]3. The only stable compound isolated from such reactions is the bis(trimethylsilyl)methyl compound Cp"2U[CH(SiMe3)2]. 

Diazo compounds generally do not undergo [3 + 2] cycloaddition with unactivated nitriles under purely thermal, noncatalyzed conditions. The formation of 4-R-5-trimethylsilyl-l//-l,2,3-triazoles from the reaction of diazo(trimethylsilyl)-methyl lithium and a broad range of nitriles [RCN R = alkyl, aryl, SEt, OPh, PO(OEt)2] appears to be an exception, but this reaction most likely occurs in a stepwise manner with initial nucleophilic attack at the nitrile (275). 

Only a few unsubstituted, non-stabilized alkyl tellurium halides were characterized or isolated. /-Butyl tellurium chloride may have been detected by l2STe-NMR spectroscopy as a minor product of the controlled chlorination of di-/-butyl ditellurium6. 2-Chlorocarbon-ylbenzyl tellurium halides were obtained as rather unstable solids by halogenolysis of tellurophthalide7 (p. 246). Tris[trimethylsilyl methyl tellurium chloride, bromide and iodide were isolated as black-blue crystals that were stable in solution and as solids8. The stability of these compounds is attributable to the steric protection of the Te —X group by the trimethylsilyl substituents. 

Tris[trimethylsilyl]methyl tellurium iodide reacted with phenylmagnesium bromidebutyl tellurium bromide with vinyl magnesium bromide, vinyl tellurium iodide with butyl and 4-methoxyphenyl magnesium bromide, and 2-propenyl tellurium iodide with 4-methoxyph-enyl magnesium bromide to give the expected unsymmetric dialkyl or alkyl aryl tellurium compounds. 

Fairly bulky alkyl substituents such as neopentyl and (trimethylsilyl)methyl are also introduced by this method (equation 2) . Unsymmetrical compounds have also been prepared from the appropriate halide and Grignard reagents. For example the synthesis of and 2 has been reported (equations 3 and 4). 

Few organoytterbium(II) alkyls have been synthesized [15,16]. The trimethyl-silyl group features prominently in ligands such as the bis(trimethylsilyl)methyl and tris(trimethylsilyl)methyl. These compounds, whose reactivity is currently... 

The use of chelation to direct the stereochemical outcome of intramolecular additions of allylsilanes to -dicarbonyl compounds can provide excellent levels of diastereoselectivity. Cyclizations of this type proceed at low temperature under mild reaction conditions and are highly chemoselective, providing routes to highly functionalized five-, six- and seven-membered rings (10 100b and 100c Scheme 47). For the cases examined, SnCU and FeCls proved to be less effective than TiCU in the cyclization of ethyl 2-alkyl-2-alkanoyl-4-(trimethylsilyl)methyl-4-pentenoate(99 n = 1 Table 13). ... 

Recent years have seen important developments in the chemistry of tin(II) compounds and compounds with multiple bonds to tin (Scheme 1-3). The cyclopentadi-enyltin(II) compounds, which are formed from CpM and SnCL, are pentahapto monomers. When R is a simple alkyl or aryl group, the stannylenes R2Sn(II) are known only as short-lived reactive intermediates, but when the organic group is bulky [e.g. bis(trimethylsilyl)methyl or 2,4,6-trisubstituted aryl], as indicated by R in Scheme 1-3, the monomeric stannylenes, R 2Sn , have been isolated, and have provided routes to the stannenes (R 2Sn=CR.2) and distannenes (R 2Sn=SnR 2), and other compounds with a multiple bond to tin. 

Eaborn for several years has been studying the properties of tris(trimethylsilyl)methyl (trisyl) compounds, particularly their silyl derivatives. 1,3-rearrangements of alkyl groups between silicon atoms has been observed, and bridged cations have been proposed as intermediates. It has recently been observed that several reactions of the iododiphenylsilyl derivative were influenced by ultraviolet irradiation. Depending on the... 

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