Generation of<i>α</i>-Nitroalkyl Radicals by Oxidation of Nitronate Anions with Cerium(IV) Ammonium Nitrate and Their Addition Reaction to Electron-Rich Olefins
作者:Noriyoshi Arai、Koichi Narasaka
DOI:10.1246/cl.1995.987
日期:1995.11
α-Nitroalkyl radicals are generated by oxidation of nitronate anions with cerium(IV) ammonium nitrate. When the reactions are carried out in the presence of electron-richolefins, such as silyl eno...
Oxidative Generation of 1-Nitroalkyl Radicals and Their Addition Reaction to Olefins
作者:Noriyoshi Arai、Koichi Narasaka
DOI:10.1246/bcsj.70.2525
日期:1997.10
1-Nitroalkyl radicals are generated by oxidation of potassium salt of 1-aci-nitroalkanes with ammonium hexanitratocerate(IV). When the oxidation is carried out in the presence of electron-rich olefins, such as silyl enol ethers, intermolecular addition of the radicals onto the olefins proceeds to afford β-nitro ketones, which are further converted to α,β-unsaturated ketones in high yield. Stereoselective
A new, practical route to enoxysilanes is described from simple enolizable aldehydes or ketones, using the trimethylchlorosilane-sodium iodide—tertiary amine reagent in acetonitrile. From certain aldehydes, an onium intermediate has been isolated. A conformational study of this onium intermediate and a thermal unimolecular syn-elimination process may explain the stereoselectivity of the reaction. Such
The synthesis of α-acetoxy sulfides and their lewis acid-mediated reactions
作者:George A. Kraus、Hiroshi Maeda
DOI:10.1016/0040-4039(95)00349-h
日期:1995.4
α-Acetoxy sulfides can be conveniently prepared by the reaction of dithioacetals with mercuric acetate at ambient temperature. They react with allyltrimethylsilane, enol silyl ethers, and cyanotrimethylsilane in the presence of SnCl4 to afford butenyl sulfides, γ-keto sulfides and α-cyano sulfides, respectively.
Sur l'obtention hautement regio-et stereoselective d'enoxysilanes par action du bis(trimethylsilyl) acetamide en milieu hmpt sur les derives carbonyles enolisables
作者:James Dedier、Pierre Gerval、Emile Frainnet
DOI:10.1016/s0022-328x(00)85896-9
日期:1980.2
The authors describe a new and general method for the preparation of enoxysilanes by silylation of enolizable aldehydes and ketones by use of bis(trimethylsilyl) acetamide in HMPT, in the presence of very small quantities of sodium metal(or another basic agent) as catalyst. This method was found to proceed rapidly, with good yields, and is highly regio-and stereo-selective (giving the Z isomer, orientation