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{{Chembox |
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| verifiedrevid = 404978297 |
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| verifiedrevid = 423547031 |
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| ImageFile = Trifluoromethyltrimethylsilane.png |
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| ImageFileL1 = Trifluoromethyltrimethylsilane.png |
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| ImageSize = 150px |
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| ImageSizeL1 = 150px |
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| IUPACName = Trimethyl(trifluoromethyl)silane |
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| ImageAltL1 = Skeletal formula of trifluoromethyltrimethylsilane |
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| OtherNames = Ruppert's Reagent; TFMTMS |
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| ImageFileR1 = Trifluoromethyltrimethylsilane-3D-balls.png |
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| Section1 = {{Chembox Identifiers |
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| ImageSizeR1 = 130 |
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| ImageAltR1 = Ball-and-stick model of the trifluoromethyltrimethylsilane molecule |
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| PIN = Trimethyl(trifluoromethyl)silane |
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| OtherNames = Ruppert's reagent; TFMTMS; CF<sub>3</sub>SiMe<sub>3</sub> |
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|Section1={{Chembox Identifiers |
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| CASNo_Ref = {{cascite|correct|??}} |
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| CASNo = 81290-20-2 |
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| CASNo = 81290-20-2 |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII = A009786QPJ |
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| PubChem = 552549 |
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| PubChem = 552549 |
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| SMILES =C(C)(C)C(F)(F)F |
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| SMILES = C(C)(C)C(F)(F)F |
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| ChemSpiderID = 480635 |
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| StdInChI = 1S/C4H9F3Si/c1-8(2,3)4(5,6)7/h1-3H3 |
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| StdInChIKey = MWKJTNBSKNUMFN-UHFFFAOYSA-N |
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|Section2={{Chembox Properties |
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| C=4|H=9|F=3|Si=1 |
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| C=4 | H=9 | F=3 | Si=1 |
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| Appearance = colorless liquid |
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| Appearance = Colorless liquid |
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| Density = 0.9626 g/cm<sup>3</sup> @ 20 °C |
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| Density = 0.9626 g/cm<sup>3</sup> at 20 °C |
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| BoilingPt = 54-55 °C |
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| BoilingPtC = 54 to 55 |
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'''Trifluoromethyltrimethylsilane''' (known as '''Ruppert-Prakash reagent''', TMSCF<sub>3</sub>) is an organosilicon compound with the formula CF<sub>3</sub>Si(CH<sub>3</sub>)<sub>3</sub>. It is a colorless liquid. The compound is a ] used in organic chemistry for the introduction of the ] ]. The compound was first prepared in 1984 by Ingo Ruppert<ref>{{Cite journal | journal = Tetrahedron Letters | volume= 25 |issue= 21 |pages= 2195–2198 | date = 1984 | title = Fluorinated organometallic compounds. 18. First trifluoromethyl-substituted organyl(chloro)silanes | last1 = Ruppert | first1 = Ingo | last2 = Schlich | first2 = Klaus | last3 = Volbach | first3 = Wolfgang| doi= 10.1016/S0040-4039(01)80208-2 }}</ref> and further developed as a reagent by ].<ref>{{Cite journal|last=Prakash|first=G. K. Surya|last2=Yudin|first2=Andrei K.|date=1997-05-01|title=Perfluoroalkylation with Organosilicon Reagents|journal=Chemical Reviews|volume=97|issue=3|pages=757–786|doi=10.1021/cr9408991|pmid=11848888|issn=0009-2665}}</ref><ref>{{Cite journal|last=Liu|first=Xiao|last2=Xu|first2=Cong|last3=Wang|first3=Mang|last4=Liu|first4=Qun|date=2015-01-28|title=Trifluoromethyltrimethylsilane: Nucleophilic Trifluoromethylation and Beyond|journal=Chemical Reviews|volume=115|issue=2|pages=683–730|doi=10.1021/cr400473a|pmid=24754488|issn=0009-2665}}</ref> |
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'''Trifluoromethyltrimethylsilane''' (often called ''Ruppert's reagent'' or ''Ruppert-Prakash reagent'') is a reagent used in organic chemistry for the introduction of the ] ]. The compound was first prepared in 1984 in Ingo Ruppert's group at the ] and introduced into the vocabulary of organic chemistry by the group of Surya Prakash at the ] five years later. |
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==Use== |
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==Preparation== |
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The reagent is prepared from ] and ] in the presence of a phosphorus(III) reagent that serves as a halogen acceptor.<ref>{{cite journal|title=1-Trifluoromethyl-1-cyclohexanol|author1=Pichika Ramaiah|author2=Ramesh Krishnamurti|author3=G. K. Surya Prakash|journal=Org. Synth.|year=1995|volume=72|page=232|doi=10.15227/orgsyn.072.0232}}</ref> |
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==Use in organic synthesis== |
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Upon treatment with a source of fluoride the compound forms an ] that attacks ] and ] to form trifluoromethyl ]s and esters to form trifluoromethyl ]. It is thus a substitute for trifluoromethyllithium, which, unlike higher perfluoroalkyllithium compounds, is not isolable since even at low temperature it rapidly decomposes to yield ] and ]. |
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In the presence of a metal salt (M<sup>+</sup> X<sup>−</sup>), the reagent reacts with ] and ] to give a trimethylsilyl ether, the net product of insertion of the carbonyl into the Si-CF<sub>3</sub> bond. ] gives trifluoromethyl ]s. The reagent also converts esters to trifluoromethyl ]. A typical initiator is a soluble fluoride-containing species such as ]; however, simple alkoxides such as KOtBu are also effective.<ref>{{cite book|title=Trifluoromethyltrimethylsilane|author1=George. A. Olah|author2=G. K. Surya Prakash|author3=Qi Wang|author4=Xing-Ya Li|author5= María Sánchez-Roselló|author6= Carlos del Pozo Losada|author7=José Luis Aceña|journal=Encyclopedia of Reagents for Organic Synthesis|year=2009|doi=10.1002/047084289X.rt253.pub2|isbn=978-0471936237}}</ref> The mechanism begins by generation of Si(CH<sub>3</sub>)<sub>3</sub>X and a highly reactive <sup>−</sup> (trifluoromethide) intermediate. The <sup>−</sup> attacks the carbonyl to generate an alkoxide anion. The alkoxide is silylated by the reagent to give the overall addition product, plus <sup>−</sup>, thus propagating an anionic chain reaction. The reagent competes with the carbonyl for the reactive intermediate, rapidly sequestering <sup>−</sup> in a reversibly-generated ] <sup>−</sup>. This ] 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<sup>+</sup>) playing a major role in controlling the overall rate.<ref>{{cite journal|title=Anion-Initiated Trifluoromethylation by TMSCF<sub>3</sub>: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR|author1=Craig P. Johnston|author2=Thomas H. West|author3=Ruth E. Dooley|author4=Marc Reid|author5= Ariana B. Jones|author6= Edward J. King|author7=Andrew G. Leach|author8=Guy C. Lloyd-Jones |journal=Journal of the American Chemical Society|volume=140|issue=35|pages=11112–11124|year=2018|doi=10.1021/jacs.8b06777|pmid=30080973|pmc=6133236|hdl=10023/16552}}</ref> |
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The reagent has largely supplanted trifluoromethyllithium, which is not isolable and rapidly decomposes to yield ] and ]. |
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==References== |
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==References== |
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* {{cite journal | journal = Chem. Rev. | year = 1997 | volume = 97 | pages = 757–86 | doi = 10.1021/cr9408991 | title = Perfluoroalkylation with Organosilicon Reagents | author = G. K. Surya Prakash; Andrei K. Yudin | pmid=11848888}} |
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