CHEMO- AND REGIOSELECTIVE REDUCTION OF α,β-EPOXY KETONES TO β-HYDROXY KETONES BY SODIUM HYDROGENTELLURIDE
作者:Atsuhiro Osuka、Koji Taka-Oka、Hitomi Suzuki
DOI:10.1246/cl.1984.271
日期:1984.2.5
α,β-Epoxy ketones were chemo- and regioselectively reduced to β-hydroxy ketones by sodium hydrogenteiiuride in good yields.
α,β-环氧酮通过氢化钠选择性地还原为β-羟基酮,产率良好。
Lithium naphthalenide induced reductive cleavage of α,β-epoxy ketones: an efficient procedure for the preparation of β-hydroxy ketones
作者:Renata Jankowska、Hsing-Jang Liu、George L. Mhehe
DOI:10.1039/a904646a
日期:——
Lithium naphthalenide presents itself as a mild and efficient reagent for the cleavage of α,β-epoxy ketones to give the corresponding β-hydroxy ketones in good yields.
1,3-Dimethyl-2-phenylbenzimidazoline (DMPBI)-Acetic Acid: An Effective Reagent System for Photoinduced Reductive Transformation of α,β-Epoxy Ketones to β-Hydroxy Ketones
aqueous solvents. When THF solutions containing aryl carbonyl possessing α,β-epoxyketones and DMPBI and acetic acid were irradiated (λ > 280 nm), β-hydroxy ketones were isolated in good to excellent yields. Photosensitized conditions (λ > 340 nm) were employed for the reactions of alkyl carbonyl possessing α,β-epoxyketones.
Both 2-(2′-hydroxyphenyl)-1,3-dimethylbenzimidazoline and 2-(4′-hydroxyphenyl)-1,3-dimethylbenzimidazoline were found to act as formal two hydrogen atom-donors for photoinduced electron transfer reactions of epoxy ketones and other carbonyl compounds.
Electrolysis in the presence of ultrasound: cell geometries for the application of extreme rates of mass transfer in electrosynthesis
作者:Frank Marken,、Richard G. Compton,、Stephen G. Davies、Steven D. Bull、Thies Thiemann、M. Luisa Sá e Melo、André Campos Neves、José Castillo、C. Gisèle Jung、André Fontana
DOI:10.1039/a701004d
日期:——
Two types of sonoelectrochemical reactors for preparative synthetic work are suggested and characterized by their performance in the reversible one electron reduction of cobalticenium cations in acetonitrile solution. The dominant effect of ultrasound is to strongly agitate the liquid phase and the corresponding parameters (mass transport coefficients) for the transport at the electrode surface are reported. An upper limit for ultrasound induced mass transport at macroelectrodes an order of magnitude beyond that achieved in conventional electrolysis is described. Further, for a synthetic scale reaction, the reductive ring opening of the α,β-epoxyketone isophorone oxide to yield the corresponding β-hydroxyketone, an improved current efficiency (3 F for a direct two electron reduction) and a clean conversion (yields up to 80% isolated) are demonstrated. The extremely high rates of mass transport achieved in the presence of ultrasound considerably enhance the performance and current efficiency in electrosynthesis by selectively increasing the rates of the mass transport controlled processes.