(Sn-Mont) was found to be a powerful heterogeneouscatalyst for the cyanosilylation of various ketones including congested ones with a bulky cyanide source, tert-butyldimethylsilyl cyanide (TBDMSCN), giving the corresponding cyanohydrin tert-butyldimethylsilyl ethers in good (85%) to excellent (>98%) yields at room temperature. Compared to the previously reported catalysts, Sn-Mont is easy to prepare, environmentally
Palladium-Catalyzed Cross-Coupling of Cyanohydrins with Aryl Bromides: Construction of Biaryl Ketones
作者:Huifang Dai、P. Andrew Evans、Jadab Majhi、Bohang Zhou、Yuxin Zhuang、Mai-Jan Tom
DOI:10.1055/a-1850-3687
日期:——
The palladium-catalyzedcross-coupling of the lithium anion of aryl tert-butyldimethylsilyl-protected cyanohydrins with arylbromides followed by in situ deprotection with fluoride ion provides a convenient and versatile approach to biaryl ketones. This protocol represents the first example of a palladium-catalyzed arylation of a cyanohydrin, which functions as an acyl anion equivalent. Hence, in contrast
P(RNCH2CH2)N: efficient catalysts for the cyanosilylation of aldehydes and ketones
作者:Brandon M. Fetterly、John G. Verkade
DOI:10.1016/j.tetlet.2005.09.032
日期:2005.11
The 1,2-addition of trialkylsilylcyanides to aldehydes and ketones produces the corresponding protected cyanohydrins in good to excellent yields when carried out at 0 degrees C to room temperature in the presence of catalytic amounts of the nonionic strong base P(RNCH2CH2)N (R = Me, i-Pr) in THF. These catalysts are easily removed from the product by hydrolysis or column filtration through silica gel. (c) 2005 Published by Elsevier Ltd.
A Novel Synthetic Approach to 2,2,2-Trifluoroethylidene Derivatives from Ketones.
An approach to 2, 2, 2-trifluoroethylidene derivatives from ketones was explored by employing the Corey-Winter's reductive elimination of 4-trifluoromethyl-1, 3-dioxolane-2-thiones to 2, 2, 2-trifluoroethylidene derivatives as a key step. The 1, 3-dioxolane-2-thione derivatives were readily prepared from ketones in five steps by sequential formation of O-silylated cyanohydrins, reduction, addition of trifluoromethyltrimethylsilane, desilylation, and formation of the 1, 3-dioxolane-2-thione system.