- Catalyst-Free and Redox-Neutral Innate Trifluoromethylation and Alkylation of Aromatics Enabled by Light
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The Minisci alkylation is useful to functionalize aromatics via alkyl radical addition. Current approaches to prepare alkyl radicals follow either oxidative or reductive pathways from various functional groups. Developing new strategy beyond these traditional methods remains elusive yet highly significant. In this article, we present a redox-neutral and catalyst-free protocol to engender alkyl radicals in the context of trifluoromethylation and general alkylation of arenes. This protocol, via the Norrish type I concept to produce alkyl radicals, accommodates various functional groups and delivers the product in good yields. This method identified a series of compounds as the trifluoromethylation and alkylation reagents assisted by light. It is expected that these compounds can find potential applications in other radical-involved reactions.
- Liu, Peng,Liu, Wenbo,Li, Chao-Jun
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supporting information
p. 14315 - 14321
(2017/10/17)
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- Reactivity of a-trifluoromethanesulfonyl esters, amides and ketones: Decarboxylative allylation, methylation, and enol formation
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The impact of α-trifluoromethanesulfonyl groups on the chemistry of various carbonyl groups is reported. Allylic α, α-dialkylated- α-trifluoromethanesulfonyl esters readily underwent decarboxylative allylation. α-Trifluoromethylsulfonyl esters, ketones, and amides were all methylated in the presence of trimethylsilyldiazomethane. Esters afforded a mixture of O-and C-methylation; however, ketones and amides offered exclusively O-methylation, with varying degrees of E/Z selectivity, thus affording ambiphilic alkenes. α-Trifluoromethanesulfonyl ketones also exhibited keto-enol tautomerism.
- Kong, Han Il,Gill, Monica A.,Hrdina, Amy H.,Crichton, Jennifer E.,Manthorpe, Jeffrey M.
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supporting information
p. 151 - 161
(2013/11/06)
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- Stereoselective synthesis of ambiphilic alkenes via regioselective methylation of α-trifluoromethanesulfonyl carbonyl compounds with trimethylsilyldiazomethane
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α-Trifluoromethanesulfonyl esters, ketones and amides are C-H acids capable of reacting with trimethylsilyldiazomethane to afford the corresponding ambiphilic alkenes. While esters were found to be non-selective, ketones were highly regioselective for O-methylation and displayed variable E/Z stereoselectivity. Amides were observed to be both highly regio- and stereoselective, affording O-methylation with exclusive formation of the Z-alkene.
- Kong, Han Il,Crichton, Jennifer E.,Manthorpe, Jeffrey M.
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supporting information; experimental part
p. 3714 - 3717
(2011/08/06)
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- Scope and limitations of functionalized acetylenic triflones in the direct alkynylation of C-H bonds
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Reactions of TIPS-substituted acetylenic triflones extends the versatility of the trifluoromethyl mediated C-H alkynylation reaction. Alkynes bearing acetylenic or propargylic oxygen functionality cannot be prepared, but silyl ethers or chlorides in remote positions may be carried through the reaction. Crown ethers are successfully monofunctionalized and distal bis-acetylenes may be employed in the title reaction.
- Xiang, Jason,Jiang, Wanlong,Fuchs
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p. 6635 - 6638
(2007/10/03)
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- Stereospecific alkenylation of C-H bonds via reaction with β- heteroatom-functionalized trisubstituted vinyl triflones
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Aryl and alkyl β-heteroatom-trisubstituted vinyl triflones react with THF and cyclohexane to undergo trifluoromethyl radical-mediated C-H functionalization reactions to afford E and Z β-heteroatom-trisubstituted olefins. Most reactions proceed with both high yield and high stereospecificity (retention of configuration). β-Substituents which have been employed in this study are iodine, bromine, fluorine, benzoate, ethylcarbonate, and phthalimide. β-Substituents bearing powerful electron- releasing groups such as alkoxy or amino render the vinyl triflone unreactive.
- Xiang, Jason,Jiang, Wanlong,Gong, Jianchun,Fuchs
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p. 4123 - 4129
(2007/10/03)
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- Improved synthesis of trifluoromethyl sulfones used as intermediates for the preparation of di- or tri-substituted olefins
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Primary and secondary trifluoromethyl sulfones (triflones) are efficiently obtained from easily available sodium trifluoromethanesulfinate (triflinate) and alkyl bromides in N,N-dimethylacetamide.This technique is more powerful than the potassium triflinate/acetonitrile system.Ethyl aconitate can be also produced in one step from ethyl bromoacetate and diisopropylethylamine, sodium triflinate being a catalyst.
- Eugene, Fabrice,Langlois, Bernard,Laurent, Eliane
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p. 301 - 310
(2007/10/02)
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- An Expedient Synthesis of Alkynyl Trifluoromethyl Sulfones
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The hiterto difficultly attainable trifluoromethyl sulfones 7 were prepared by the reaction of alkynyl sodium salts 6 with trifluoromethanesulfonic anhydride (1) in modest to good yields.The reactivity of 7 with different nucleophiles was studied.
- Hanack, Michael,Wilhelm, Baerbl,Subramanian, L. R.
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p. 592 - 595
(2007/10/02)
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- REACTIVE ALKYNYL PERFLUOROALKANESULFONES
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The alkynylperfluoroalkanesulfones 5a-e have been prepared and their cycloaddition reactivity towards dienes and diazomethane has been studied.The faster reaction rate of 5b with cyclopentadiene than 5a and vice versa with tetracyclone (6) has been explained on steric and electronic affects.The alkynylperfluoroalkanesulfones are very reactive towards nucleophilic additions.Attempts to prepare the highly reactive bis-perfluoroalkanesulfonylacetylene (21) in the presence of cyclopentadiene led to the isolation of products 22, 23 and 24.
- Massa, F.,Hanack, M.,Subramanian, L. R.
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p. 601 - 615
(2007/10/02)
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