Organocatalytic Functionalization of Carboxylic Acids: Isothiourea-Catalyzed Asymmetric Intra- and Intermolecular Michael Addition−Lactonizations
摘要:
Tetramisole promotes the catalytic asymmetric intramolecular Michael addition-lactonization of a variety of enone acids, giving carbo- and heterocyclic products with high diastereo- and enantiocontrol (up to 99:1 dr, up to 99% ee) that are readily derivatized to afford functionalized indene and dihydrobenzofuran carboxylates. Chiral isothioureas also promote the catalytic asymmetric intermolecular Michael addition-lactonization of arylacetic acids and alpha-keto-beta,gamma,-unsaturated esters, giving anti-dihydropyranones with high diastereo- and enantiocontrol (up to 98:2 dr, up to 99% ee).
A regiospecific and stereospecific route to enol carbonates and carbamates: closer look at a “naked anion”
作者:R.A. Olofson、John Cuomo
DOI:10.1016/s0040-4039(00)71514-0
日期:1980.1
A fluoride ion catalyzed reaction which affords the title compounds in good yield from enolsilylethers is described.
描述了一种氟离子催化的反应,其从烯醇甲硅烷基醚以良好的产率提供标题化合物。
Preparation of Silyl Enol Ethers Using (Bistrimethylsilyl)acetamide in Ionic Liquids
作者:Michael Smietana、Charles Mioskowski
DOI:10.1021/ol015602h
日期:2001.4.1
[reaction: see text]. Ionic liquids have been used for the preparation of silylenolethers from aldehydes and ketones with (bistrimethylsilyl)acetamide (BSA) in good yields.
α-Nitration of Ketones <i>via</i> Enol Silyl Ethers. Radical Cations as Reactive Intermediates in Thermal and Photochemical Processes
作者:Rajendra Rathore、Jay K. Kochi
DOI:10.1021/jo9515687
日期:1996.1.1
silyl ether (ESE) to TNM results in the radical ion triad [ESE(*)(+), NO(2)(*), C(NO(2))(3)(-)]. A subsequent fast homolytic coupling of the cation radical of the enol silyl ether with NO(2)(*)() leads to the alpha-nitro ketones. The use of time-resolved spectroscopy and the disparate behavior of the isomeric enol silyl ethers of alpha- and beta-tetralones as well as of 2-methylcyclohexanone strongly
Easy Preparation of Enoxysilanes from Aldehydes and Ketones Catalyzed by Samarium Diiodide
作者:Jérome Hydrio、Pierre Van de Weghe、Jacqueline Collin
DOI:10.1055/s-1997-1514
日期:1997.1
Ketones and α-substituted aldehydes are converted to trimethylsilyl enol ethers by reaction with the trimethylsilyl ketene acetal of methyl isobutyrate in dichloromethane in presence of a catalytic amount of samarium diiodide.
reactions of enol ethers (ROCC, R = alkyl, silyl) with zinc carbenoid reagents were found to give allylic ethers in several cases along with the expected cyclopropylethers. The ratio of these two products was highly dependent on the concentration of the reaction mixture. Thus, the selective formation of each product was conveniently attained by merely changing the amounts of the solvent used. Zinc iodide