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
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
Efficient Synthesis of 6-Trimethylsiloxy- and 6-(Trimethylsilyl)-methyl-3-phenyl-5, 6,dihydro-4<i>H</i>-1,2-oxazines by Cycloaddition of α-Nitrosostyrene to Silyl Enol Ethers and Allyltrimethylsilane
作者:Claudia Hippeli、Hans-Ulrich Reissig
DOI:10.1055/s-1987-27856
日期:——
The title compounds 3 are prepared in good yield from silyl enol ethers 1 and α-nitrosostyrene 2, generated in situ from α-chloroacetophenone oxime 4. Allyltrimethylsilane smoothly affords cycloadduct 5 which could be opened to the unsaturated ketone 6 or amino olefin 7.
Radical-chain isomerisation of allyl silyl ethers to silyl enol ethers in the presence of thiols as polarity reversal catalysts
作者:Alistair J Fielding、Brian P Roberts
DOI:10.1016/s0040-4039(01)00630-x
日期:2001.6
radical-chain isomerisation of allylsilylethers to silyl enol ethers takes place on heating in the presence of an initiator and an arenethiol as a protic polarity reversal catalyst; pentafluorothiophenol is particularly effective in this role. The reaction complements the transition-metal-catalysed isomerisation and could be useful for the preparation of silyl enol ethers from readily available allylic