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| Names | |||
|---|---|---|---|
| Preferred IUPAC name
Trimethyl(trifluoromethyl)silane | |||
| Other names
Ruppert's reagent; TFMTMS; CF3SiMe3 | |||
| Identifiers | |||
3D model (JSmol) |
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| ChemSpider | |||
| ECHA InfoCard | 100.106.346 
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PubChem CID |
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| UNII | |||
CompTox Dashboard (EPA) |
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| Properties | |||
| C4H9F3Si | |||
| Molar mass | 142.196 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Density | 0.9626 g/cm3 at 20 °C | ||
| Boiling point | 54 to 55 °C (129 to 131 °F; 327 to 328 K) | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Trifluoromethyltrimethylsilane (known as Ruppert-Prakash reagent, TMSCF3) is an organosilicon compound with the formula CF3Si(CH3)3. It is a colorless liquid. The compound is a reagent used in organic chemistry for the introduction of the trifluoromethyl group. The compound was first prepared in 1984 by Ingo Ruppert[1] and further developed as a reagent by G. K. Surya Prakash.[2][3]
The reagent is prepared from trimethylsilyl chloride and bromotrifluoromethane in the presence of a phosphorus(III) reagent that serves as a halogen acceptor.[4]
In the presence of a metal salt (M+X−), the reagent reacts with aldehydes and ketones to give a trimethylsilyl ether, the net product of insertion of the carbonyl into the Si-CF3 bond. Hydrolysis gives trifluoromethyl methanols. The reagent also converts esters to trifluoromethyl ketones. A typical initiator is a soluble fluoride-containing species such as tetrabutylammonium fluoride; however, simple alkoxides such as KOtBu are also effective.[5] The mechanism begins by generation of Si(CH3)3X and a highly reactive [CF3]− (trifluoromethide) intermediate. The [CF3]− attacks the carbonyl to generate an alkoxide anion. The alkoxide is silylated by the reagent to give the overall addition product, plus [CF3]−, thus propagating an anionic chain reaction. The reagent competes with the carbonyl for the reactive intermediate, rapidly sequestering [CF3]− in a reversibly-generated -ate complex [(CF3)2Si(CH3)3]−. This -ate complex is unable to react directly with the carbonyl, resulting in powerful inhibition of the chain reaction by the reagent. This inhibitory process is common to all anion-initiated reactions of the reagent, with the identity of the counter-cation (M+) playing a major role in controlling the overall rate.[6]
The reagent has largely supplanted trifluoromethyllithium, which is not isolable and rapidly decomposes to yield lithium fluoride and difluorocarbene.
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