Trialkylsilanes oxidation

Recently, another type of catalytic cycle for the hydrosilylation has been reported, which does not involve the oxidative addition of a hydrosilane to a low-valent metal. Instead, it involves bond metathesis step to release the hydrosilylation product from the catalyst (Scheme 2). In the cycle C, alkylmetal intermediate generated by hydrometallation of alkene undergoes the metathesis with hydrosilane to give the hydrosilylation product and to regenerate the metal hydride. This catalytic cycle is proposed for the reaction catalyzed by lanthanide or a group 3 metal.20 In the hydrosilylation with a trialkylsilane and a cationic palladium complex, the catalytic cycle involves silylmetallation of an alkene and metathesis between the resulting /3-silylalkyl intermediate and hydrosilane (cycle D).21... 

Trifluoromethyl)tributyl tin, prepared from (trifluoromethyl)trimethylsilane and bis(tributyltin) oxide, has been reported81 to react with disilyl sulphides to give the corresponding (trifluoromethyl)di- and (trifluoromethyl)trialkylsilanes. 

Trimethy (trifluoromethyl)si ane can be converted into tributyl(trifluoromethyl)tin (40) in quantitative yield by treatment with bis(tributyltin) oxide in tetrahydrofuran under fluoride ion initiation.129 Tributyl(trifluoromethyl)tin readily trifluoromethylates disilyl sulfides at room temperature giving the corresponding trifluoromethylated di- and trialkylsilanes 41 in high yields. This method provides a new approach for the preparation of silicon-based trifluoro-methylating reagents via transtrifluoromethylation of compounds containing Si — S bonds. 

The oxidative addition of trialkylsilane to the mthenium carbonyl species 22 gives 23, in which a 1,3-shift of R3Si from the mthenium to the carbonyl oxygen atom... 

As a terf-aralkyl sulfide, 5-trityl (Trt)t 29i protection became important in peptide chemistry only upon discovery of its quantitative cleavage with metal ions,t l or by oxidative iodinolysis, as well as upon the development of optimized scavengers capable of preventing retritylation of the thiol group under acidic conditions,t l particularly when trialkylsilanes are included as scavengers.Further enhancement of the acid lability of 5-trityl was obtained, as expected, with the 4-methoxytrityl (Mmt) group (Scheme 11).P 36]... 

When trialkylsilanes are employed, vinylsilane is often produced as the main product. This oxidative hydrosilylation can be carried out with [Me3SiCo(CO)4], [Cp 2Rh2Cl4] (equation 29), [ Ir(OMe)(COD))2], [Cp Fe(CO)2SiMe3], or Na[HRu3(CO)i ] catalysts. This unusual reaction is understood in terms of silylmetallation rather than the ordinary hydrometallation mechanism. ... 

Carbonyl replacement dominates the observed photoreactions of Co complexes, and with CO-like ligands, total substitution is possible. Table 1 lists examples. The complex CofCOjNO is unusual in that the primary photoprocess is a linear to bent NO transformation, followed by an associative displacement of CO from this shortlived intermediate. Photolysis in CHClj leads to incorporation of chloride in the complex if PPhj is present, then Co(PPh3)2Cl2 is formed " if NO is present then [Co(NO)2C1 j is generated Trialkylsilane exchange in RjSiCo(CO) (Table 1) proceeds via oxidative addition of RjSiH to the intermediate formed by CO loss, followed by reductive elimination of R SiH. This is true for surface-confined analogues as well d. 

Finally, dimethyldioxirane is a convenient oxidant for converting silanes into their silanols by Si —H insertion. When optically active trialkylsilanes are used, the Si — H insertion proceed with complete retention of configuration [38]. The advantage of this highly selective method of hydroxylating silanes is the fact that under the strictly neutral conditions no siloxanes are produced. Likewise,... 

Ru3(CO)7(/r3-7 7 7 -acenaphthalene) reacts with stoichiometric amounts of trialkylsilanes with loss of CO and concomitant oxidative addition of the Si-H bond. Under appropriate conditions, the same cluster catalyzes the... 

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