Trialkylsilyl halide

The reactions of enamines (516) with trialkylsilyl halides in the presence of triethylamine (or other nitrogen bases) produce 3-halomethyl-substituted oxazines (517) (or 517 ) in good yields (Scheme 3.268) (472). 

Another class of carbanion derivatives that has received a lot of attention are the azaheterocyclic trialkylsilanes, which are readily obtained by reaction of the appropriate carbanion with trialkylsilyl halides. These compounds are capable of reacting directly as heteroaryl anion equivalents... 

Flood reaction. Formation of trialkylsilyl halides from hexaalkyldisiloxanes using concentrated sulfuric acid in the presence of ammonium chloride or fluoride, or by treatment of the intermediate silane sulfates with hydrochloric acid in the presence of ammonium sulfate. 

Trialkylsilyl halides show a great propensity to react with the oxygen rather than the carbon of enolate anions. Stork showed that 0-alkylation allows enolates to be trapped as the trialkylsilyl enol ether, which is most useful for kinetic enolates in which a lithium enolate (such as the kinetic enolate derived from 2-methyl-cyclohexanone and LDA) is reacted with trimethylsilyl chloride to give an isolable intermediate, 112. jjig enolate is trapped with high efficiency, and conversion to the enolate is readily accomplished by treatment with methyllithium, which generates the kinetic enolate (113) and the volatile trimethylsilane (Me3SiH). This... 

This reaction was initially reported by Flood in 1933. It is a synthesis of trialkylsilyl halide involving the treatment of the mixture of di-trialkylsilyl oxide and concentrated sulfuric acid with sodium halide or ammonium halide. The resulting trialkylsilyl halide can be extracted by petroleum ether and then purified via distillation. It was found that when di-trimethylsilyl oxide is mixed with concentrated sulfuric acid, trimethylsilyl sulfate can be isolated as a white crystalline (m.p., Sb-SS C), which forms trimethylsilyl halide when it reacts with ammonium halide. The reaction has been improved by continuous extraction of the reaction mixture with pentane to yield more and purer trialkylsilyl halide and by the addition of ammonium bisulfate to the reaction mixture. ... 

Another type of protecting group for alcohols is a silyl ether. A silyl ether has the general formula of R —O—SiR3. The reaction of an alcohol with a trialkylsilyl halide leads to a trialkylsilyl ether in near-quantitative yield... 

The synthesis of aramids from N-silylated amines has been employed because N-silylated aromatic amines show higher reactivity relative to the parent diamines and the resulting trialkylsilyl halide does not lower the reactivity of unreacted amine functionality as is the case with amine protonation... 

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