Synthesis of trifluoromethyl ethers and difluoro(methylthio)methyl ethers by the reaction of dithiocarbonates with IF5-pyridine-HF
作者:Toshiya Inoue、Chiaki Fuse、Shoji Hara
DOI:10.1016/j.jfluchem.2015.04.016
日期:2015.11
Trifluoromethyl ether and difluoro(methylthio)methyl ether of phenols and aliphatic alcohols were selectively synthesized from the corresponding dithiocarbonates. When IF5-pyridine-HF was used alone in the reaction of the dithiocarbonate, the difluoro(methylthio)methyl ether was selectively formed. On the other hand, by the additional use of Et3N-6HF with IF5-pyridine-HF, trifluoromethyl ether was
A new ionic liquid [bdmim][F] has been prepared and fully characterized. Its potential as a fluoride source for the desulfurization–fluorination process has been evaluated with success. The carbon–sulfur double bond of xanthates and thiocarbonates has been difluorinated to give rise to small libraries of halogenated ketals and thioketals.
Treatment of xanthates R-OC(S)SMe with (HF)9/Py and 1,3-dibromo-5,5-dimethylhydantoin gives trifluoromethyl ethers R-OCF3 through intermediates R-OCF2SMe, which could be isolated upon treatment of xanthates with n-Bu4N+H2F3− and N-bromosuccinimide.
Expanding the scope of methyl xanthate esters - From Barton-McCombie reaction auxiliary to versatile protective group
作者:Karin Thorsheim、Sophie Manner、Ulf Ellervik
DOI:10.1016/j.tet.2017.09.022
日期:2017.11
presented as a versatile protective group for alcohols. Hydroxyl groups can easily be transformed into methyl xanthate esters by several methods and are commonly used as an auxiliary in the Barton-McCombiereaction. We show that these methyl xanthate esters can readily and chemoselectively be cleaved under mild conditions by the action of diethylenetriamine using microwave heating. This method is orthogonal
Trifluoromethyl ethers R-OCF3 are easily synthesized from the corresponding dithiocarbonates R-OCS2Me (R = aryl or primary alkyl) by a reagent system consisting of 70% HF/pyridine and an N-halo imide. When the reaction is applied to R-OCS2Me wherein R = secondary alkyl, tertiary alkyl, or benzylic group, fluorination leading to the corresponding alkyl fluorides R-F is achieved, whereas a combination