Des eseses alcoxytitaniumgenerees par traitement de trichlorotitanio-3propionates d'alkyles (I) avec un demi-equivalent d'alcoolate de titane (IV) sont plus reactors que I, Fournissant des voies d'acces a des hydroxy-4esters, γ-内酯和环丙烷羧酸盐。同烯醇化物形成机制的讨论
Reactions d'addition sur les composes carbonyles, allylation, arylation, vinylation et acylation en presence ou non de catalyseurs
反应 d'addition sur les 组成羰基、烯丙基化、芳基化、乙烯基化和酰化在非脱催化剂的存在下
Stereocontrolled construction of oxygenated steroidal side chains. Synthesis and stereochemistry of depresosterol
作者:Eiichi Nakamura、Isao Kuwajima
DOI:10.1021/ja00293a051
日期:1985.4
On prepare le sterol du titre a partir de l'acetoxy-3 pregnene-5-carbaldehyde-20. On confirme la stereochimie par la synthese des deux epimeres possibles C(24). On prepare egalement des precurseurs de l'ecdysone et du dimethylgorgosterol
在制备 le sterol du titre a partir de l'acetoxy-3 pregnene-5-carbaldehyde-20。在confirme lastereochimie par la synthese des deux epimeres possibles C(24)。关于制备蜕皮激素和二甲基戈尔甾醇的前体
Palladium-catalyzed arylation of siloxycyclopropanes with aryl triflates. Carbon chain elongation via catalytic carbon-carbon bond cleavage
La reaction a une utilite synthetique generale et permet d'obtenir des composes carbonyles (cetones, aldehydes, esters) β-aryles
La 反应 a une utilite synthetique generale et permet d'obtenir des composes carbonyles (cetones, aldehydes,esters) β-aryles
Synthesis of 1,4-keto esters and 1,4-diketones via palladium-catalyzed acylation of siloxycyclopropanes. Synthetic and mechanistic studies
作者:Tsutomu Fujimura、Satoshi Aoki、Eiichi Nakamura
DOI:10.1021/jo00008a043
日期:1991.4
The reaction of a variety of siloxycyclopropanes with acid chlorides in the presence of a catalytic amount of a palladium/phosphine complex gives 1,4-dicarbonyl compounds to good yield. 1-Alkoxy-1-(trialkylsiloxy)-cyclopropanes react with both aromatic and aliphatic acid chlorides in chloroform to give 1,4-keto esters. Synthesis of 1,4-diketones by the acylation of 1-alkyl- or 1-aryl-1-siloxycyclopropanes has been achieved by carrying out the reaction if HMPA under 10-20 atm of carbon monoxide. Kinetics studies and product analysis revealed the unique mechanism of this reaction, which involves rate-determining cleavage of the strained cyclopropane carbon-carbon bond with a coordinatively unsaturated acylpalladium chloride complex. Ab initio calculations of hydroxylated cyclopropane model compounds showed that the unique reactivities of the siloxycyclopropanes may be correlated with the molecular orbital properties of these compounds rather than their ground-state structural properties.
Palladium catalyzed reactions of propionate homoemolate. Arylation, vinylation, and acylation