Microwave-promoted TBAF-catalyzed SNAr reaction of aryl fluorides and ArSTMS: An efficient synthesis of unsymmetrical diaryl thioethers
Microwave irradiation was found to promote tetrabutylammonium fluoride catalyzed nucleophilic aromatic substitution of aryl fluorides and arylthiotrimethylsilanes, affording high yields of unsymmetrical diaryl thioethers efficiently under mild, transition-metal- and base-free conditions. Microwave showed unusual improvement on the reaction in not only the conditions and reaction rate, but also in selectivity and substrate scope. Georg Thieme Verlag Stuttgart - New York.
Ortho-selectivity in SNAr substitutions of 2,4-dihaloaromatic compounds. Reactions with anionic nucleophiles
The nucleophilic addition of organic anions to aromatic compounds with halogens positioned both ortho and para to activating groups was studied in a variety of solvents. Substrates showed strong preferences for ortho substitution in most cases. Evidence is presented for activating group-dependent coordination, which contributes to very high ortho-selectivity in nonpolar solvents. This also drives the overall reaction rate in these solvents, and is of close to the same magnitude of rate increase derived from polar solvents. para-Products are maximized by using crown ethers in protic solvents. Solvent effects overall are very different from corresponding reactions with amine nucleophiles due primarily to the different charges present in the transition states, and to solvation of the nucleophile.
Wendt, Michael D.,Kunzer, Aaron R.
scheme or table
p. 3041 - 3044
(2010/07/18)
TBAF-catalysed facile synthesis of unsymmetrical diaryl thioethers via mild SNAr reactions
By using tetrabutylammonium fluoride as the catalyst, the synthesis of unsymmetrical diaryl thioethers could be easily achieved in high yields via a mild nucleopilic aromatic substitution reaction of aryl fluorides and phenylthiotrimethylsilane.
Yu, Baohua,Zang, Xufeng,Yu, Xiaochun,Xu, Qing
experimental part
p. 351 - 353
(2010/10/04)
Certain azaphenoxathiin compounds
A pharmacological composition useful as potential central nervous system depressants and weight control agents in animals and humans comprising a substituted aromatic Tricyclic and Pentacyclic sulfide wherein the aromatic is phenyl, pyridyl, pyrazidyl, pyrimidyl, and isosteric substitutions including elements in Group VI-a of the Periodic Table.
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(2008/06/13)
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