Titanocene and zirconocene ketene acetal derivatives have been prepared by reaction of the respective metallocene dichloride with the lithium enolate of isobutyric acid methyl ester. The crystalstructure of (C5H5)2Ti(Cl)OC(OCH3)C(CH3) is reported.
通过使相应的茂金属二氯化物与异丁酸甲酯的烯醇锂反应,可以制备钛茂和锆茂乙烯缩醛衍生物。报告了(C 5 H 5)2 Ti(Cl)OC(OCH 3)C(CH 3)的晶体结构。
Novel 1,4-asymmetric induction in nucleophilic 1,2-additions to chiral γ-amino enals
作者:M. T. Reetz、Fan Wang、K. Harms
DOI:10.1039/c39910001309
日期:——
γ-Dibenzylamino enals 3a with the E-configuration derived from amino acids 1 react diastereoselectively with cuprates in an unexpected 1,2-manner, while the analogues 3b with the Z-configuration undergo diastereoselective additions with organolithium reagents.
Highly stereoselective preparation of nitro olefins and nitro dienes by the addition-elimination of copper-zinc organometallics to β-alkylthio and β-phenylsulfonyl nitro olefins
作者:Carole Retherford、Paul Knochel
DOI:10.1016/s0040-4039(00)79462-7
日期:1991.1
onyl ethylene 2a gave highly functionalized pure (E) nitroolefins and stereoselectively (1E, 3E) and (1E, 3Z)-1-nitrodienes in excellent yields. β-Alkylthio nitroolefins such as 2-ethylthio-1-nitro-1-cyclohexene 2b and 2,2-dimethylthio-1-nitroethylene 12 were found to have a similar behavior. This methodology allowed an expeditive preparation of the triene 5 which underwent an extremely mild silica
An Efficient and General Entry to (<i>Z</i>)-<i>α</i>-Fluoro-<i>β</i>-substituted Acrylaldehydes Based on the Coupling Reaction of<i>α</i>-Fluoro-<i>β</i>-amino Acrylaldehydes with Organolithium Reagents
of polyfluoroalkenyl tosylates (1) with dialkylamines in the presence of triethylamine and a catalytic amount (10 mol%) of tetrabutylammonium fluoride (TBAF), reacted smoothly with various organolithiumreagents at −78 °C for 0.5 h, followed by hydrolysis with 10% hydrochloric acid at room temperature for 1 h to afford the corresponding (Z)-α-fluoro-β-substituted acrylaldehydes (3) via allylic rearrangement
Reaction of various -substituted -(α-methoxyphenacyl)anilines with lithiobutyrate in excess gives,in good yield, compounds - through a regiocontrolled process.