Selective synthesis of unsymmetrical ethers from different alcohols catalyzed by sodium bisulfite
作者:Jun-Lai Yu、Hui Wang、Kai-Feng Zou、Jia-Rui Zhang、Xiang Gao、Dan-Wei Zhang、Zhan-Ting Li
DOI:10.1016/j.tet.2012.10.032
日期:2013.1
ethers from alcohols catalyzed by sodium bisulfite is reported. The procedure enables the direct dehydration of primary, secondary, and tertiary benzylicalcohols with aliphatic alcohols in the absence of solvent to selectively produce unsymmetrical ethers in high yields with low catalyst loading. No symmetrical ethers are generated in the reactions. The etherification of a chiral secondary benzyl alcohol
Chemoselective Formation of Unsymmetrically Substituted Ethers from Catalytic Reductive Coupling of Aldehydes and Ketones with Alcohols in Aqueous Solution
作者:Nishantha Kalutharage、Chae S. Yi
DOI:10.1021/acs.orglett.5b00553
日期:2015.4.3
A well-defined cationic Ru–H complex catalyzes reductive etherification of aldehydes and ketones with alcohols. The catalytic method employs environmentally benign water as the solvent and cheaply available molecular hydrogen as the reducing agent to afford unsymmetrical ethers in a highly chemoselective manner.
Oligosaccharide Analogues of Polysaccharides. Part 3. A new protecting group for alkynes: Orthogonally protected dialkynes
作者:Chengzhi Cai、Andrea Vasella
DOI:10.1002/hlca.19950780319
日期:1995.5.10
hydroxysulfide 16 with 15. The OH group of 27 was protected to yield the [dimethyl(oxy)propyl]dimethylsilyl}acetylenes (DOPSA's) 21, 28, and 29. The orthogonallyprotected acetylenes 20–22, 28, and 29 were de-trimethylsilylated to the new monoprotected acetylene synthons 30–34. The scope of the orthogonal protection was checked by regioselective deprotection of the dialkynes 39–42 (Scheme 4), prepared by alkylation
通过在质子溶剂中(4)用碱处理,或在暴露OH基团之后,在质子惰性溶剂中用催化量的碱(5和8)处理3型二元炔(方案1)的区域选择性脱保护。在ME 3的Si-保护12(方案2)是惰性的催化丁基锂/ THF其转化11到9,而ķ 2 CO 3 / MeOH中转化的两个10到9,和12到13,表明需要更受阻的(羟丙基)甲硅烷基取代基。17–19(方案3)中的碳负离子的C-甲硅烷基化反应生成15的碳负离子导致20-22,但以合理的收率仅获得22。因此,关键中间体27是通过逆布鲁克重排23制备的,该逆向布鲁克重排是通过将羟基硫化物16与15进行甲硅烷基化而制得的。OH基团的27是受保护的,得到[ d imethyl(氧)p丙基]二甲基甲硅烷}乙炔(DOPSA的)21,28和29。正交保护的乙炔20–22、28和29被去三甲基甲硅烷基化为新的单保护的乙炔合成子30–34。正交的保护范围是由dialkyn
Water Compatible Gold(III)-Catalysed Synthesis of Unsymmetrical Ethers from Alcohols
作者:Ana B. Cuenca、Gisela Mancha、Gregorio Asensio、Mercedes Medio-Simón
DOI:10.1002/chem.200701134
日期:2008.2.8
preparation of unsymmetricalethersfromalcohols catalysed by the simplest and least expensive gold catalyst, NaAuCl(4), is described for the first time. The procedure enables the etherification of benzylic and tertiary alcohols with moderate to good yields under mild conditions with low catalyst loading. Symmetrical ethers, the usual side products in the etherification of alcohols, were not detected