- KF/clinoptilolite: An efficient promoter for the synthesis of thioethers
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Potassium fluoride impregnated on natural zeolite as a new solid base system effectively catalyzes the coupling of thiophenols with electron-deficient fluoro-, chloro- and bromo-arenes in DMSO. This versatile and efficient solid base has been demonstrated to afford the corresponding desired products in good to excellent yields. This procedure provides a convenient, efficient and practical method for the preparation of diaryl thioethers.
- Salmanpour, Sadegh,Khalilzadeh, Mohammad A.,Hosseini, Abolfazl
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p. 339 - 344
(2013/07/28)
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- Synthesis of diaryl ethers, diaryl thioethers, and diarylamines mediated by potassium fluoride-alumina and 18-crown-6: Expansion of scope and utility
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An efficient alternative to the Ullmann ether synthesis of diaryl ethers, diaryl thioethers, and diarylamines involving the S(N)Ar addition of a phenol, thiophenol, or aniline to an appropriate aryl halide, mediated by potassium-fluoride alumina and 18-crown-6 in acetonitrile or DMSO, is described. Expansion of the reaction conditions to include DMSO as solvent has resulted in a far greater range of substitution patterns permitted on the electrophile. For example, it was found that electronically unfavorable 3- chlorobenzonitrile could be condensed with 3-methoxyphenol to form the corresponding diaryl ether in 66% yield, a combination not normally amenable to Ullmann coupling. Electron-withdrawing groups present on the electrophile may be as diverse as nitro, cyano, formyl, acetyl, ester, amide, and even aryl. The method features a simple reaction procedure that provides products in generally good to excellent purified yields.
- Sawyer, J. Scott,Schmittling, Elisabeth A.,Palkowitz, Jayne A.,Smith III, William J.
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p. 6338 - 6343
(2007/10/03)
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