- Trifluoromethylation of nonenolizable carbonyl compounds with a stable piperazino hemiaminal of trifluoroacetaldehyde
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A new stable hemiaminal of fluoral (1) can easily be obtained from the methyl hemiketal of fluoral and N-benzylpiperazine. This white crystalline compound can be used under basic conditions as an efficient nucleophilic trifluoromethylating reagent towards nonenolizable carbonyl compounds.
- Billard, Thierry,Langlois, Bernard R.,Blond, Gaelle
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p. 1467 - 1471
(2007/10/03)
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- Nucleophilic trifluoromethylation of carbonyl compounds and disulfides with trifluoromethane and silicon-containing bases
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Provided that DMF (or another N,N-dialkylformamide) is present in the reaction medium, at least in a catalytic amount, fluoroform trifluoromethylates efficiently carbonyl compounds, even enolizable ones, when opposed to (TMS)2N- M+, generated in situ from N(TMS)3 and M+ F- or RO- Na+. When F- is used in a catalytic amount, silylated α-(trifluoromethyl)carbinols are obtained: In this case, the four-component system HCF3/N(TMS)3/catalytic F-/catalytic DMF behaves like the Ruppert's reagent, especially as far as nonenolizable carbonyl compounds are concerned (CF3SiMe3 remains more efficient for enolizable carbonyl compounds). This process involves an adduct between DMF and -CF3 which is the true trifluoromethylating agent. In the same way, fluoroform efficiently trifluoromethylates disulfides and diselenides when deprotonated with a strong base selected from t-BuOK or N(SiMe3)3/Me4NF (or TBAT). t-BuOK is more adapted to the trifluoromethylation of awl disulfides whereas N(SiMe3)3/F- is Well suited to that of aliphatic disulfides.
- Large,Roques,Langlois
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p. 8848 - 8856
(2007/10/03)
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- Substituent Effects on the Solvolysis of 1,1-Diphenyl-2,2,2-trifluoroethyl Tosylates: Comparison between Symmetrically Disubstituted and Monosubstituted Systems
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The solvolysis rates of 1-(substituted phenyl)-1-phenyl-2,2,2-trifluoroethyl and 1,1-bis(substituted phenyl)-2,2,2-trifluoroethyl tosylates or bromides were conductimetrically measured at 25.0 °C in 80% aqueous ethanol. The substituent effects on these so
- Fujio, Mizue,Morimoto, Hiroshi,Kim, Hyun-Joong,Tsuno, Yuho
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p. 1403 - 1411
(2007/10/03)
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