Silylenolether-Funktionalisierung, 3. Mitt. Regioselektive Acylierung von Trimethylsilylenolethern mit 2-Alkoxy-1,3-dioxolanen ? Synthese von ?- und ?-gesch�tzten Dicarbonylverbindungen
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
Alkylation and arylation of 2-trimethylsiloxyallyl halides with lithium dialkyl- and diarylcuprate, respectively, gave silylenolethers in a regiospecific manner.
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
Highly selective, kinetically controlled enolate formation using lithium dialkylamides in the presence of trimethylchlorosilane
作者:E.J. Corey、Andrew W. Gross
DOI:10.1016/s0040-4039(00)99920-9
日期:1984.1
The deprotonation of ketones and esters with lithium dialkylamides in the presence of trimethylchlorosilane leads to enhanced selectivity for the kinetically generated enolate. Lithium -octyl--butylamide is shown to be superior to lithiumdiisopropylamide in the regio-selective generation of enolates and in the stereoselective formation of enolates.
results in the formation of the corresponding silyl enolethers or β-ketosilanes. The relative ratio of these products varies with the ylide conditions and the stability of ylide used. It is noteworthy that silyl enolethers were formed under the salt-free ylide conditions, and that β-ketosilanes were yielded in the presence of soluble inorganic salts in THF, selectively. The formation of both products