ASYMMETRIC CYCLOPROPANATION OF ELECTRON-DEFICIENT OLEFINS WITH DIAZO REAGENTS
申请人:Zhang X. Peter
公开号:US20100076239A1
公开(公告)日:2010-03-25
Cobalt-catalyzed asymmetric cyclopropanation of electron-deficient olefins.
钴催化的电子不足烯烃不对称环丙烷化。
On the Mechanism of Ylide-Mediated Cyclopropanations: Evidence for a Proton-Transfer Step and Its Effect on Stereoselectivity
作者:Samantha L. Riches、Chandreyee Saha、Noelia Fontán Filgueira、Emma Grange、Eoghan M. McGarrigle、Varinder K. Aggarwal
DOI:10.1021/ja910631u
日期:2010.6.9
with chiral sulfur ylides. It had previously been found that semi-stabilized sulfoniumylides (e.g., Ph-stabilized) reacted with cyclic and acyclic enones and substituted acrylates with high ee and that stabilized sulfoniumylides (e.g., ester-stabilized) reacted with cyclic enones again with high ee. The current study has focused on the reactions of stabilized sulfoniumylides with acyclic enones
在本文中,我们描述了迈克尔受体与手性硫叶立德环丙烷化的研究。先前已经发现,半稳定的锍叶立德(例如,Ph-稳定的)与环状和非环状烯酮以及取代的丙烯酸酯反应,具有高 ee 并且稳定的锍叶立德(例如,酯稳定的)再次与具有高 ee 的环烯酮反应. 目前的研究集中在稳定的锍叶立德与无环烯酮的反应上,这些反应出乎意料地降低了 ee。此外,在与甲基乙烯基酮 (MVK) 的反应中观察到 ee 与叶立德稳定性的明显相关性:酮稳定的叶立德产生 25% ee,酯稳定的叶立德产生 46% ee,酰胺稳定的叶立德产生 89% ee。据信,甜菜碱形成后,会出现一个不寻常的质子转移步骤,这会损害该过程的对映选择性。因此,在将稳定的叶立德添加到迈克尔受体后,甜菜碱中间体内的快速和可逆的分子内质子转移,在闭环之前,导致 ee 的侵蚀。最稳定的叶立德(酮)发生最大程度的质子转移。当用氘标记的锍叶立德进行相同的反应时,在所有情况下都观察到更高的
The tandem intermolecular Paternò–Büchi reaction: formation of tetrahydrooxepins
作者:Chee Yong Gan、John N. Lambert
DOI:10.1039/a802922i
日期:——
[2 + 2] photocycloaddition between carbonyl compounds and electron rich alkenes to generate oxetane products. By the introduction of substituted cyclopropyl rings to the alkene components, the utility of this reaction has been extended to facilitate the synthesis of substituted tetrahydrooxepins. It is proposed that initial addition of oxygen radicals to cyclopropyl enol ethers generates cyclopropylmethyl
(EN) The present invention provides compounds of formula (I) in which R is as defined in the specification, or a pharmaceutically acceptable metabolically labile ester or amide thereof, or a pharmaceutically acceptable salt thereof, which are useful as antagonists of one or more of the actions of L-glutamate at metabotropic excitatory amino acid receptors.(FR) Cette invention concerne des composés de formule (I), dans laquelle R est tel que défini dans le descriptif, ou un ester ou amide pharmaceutiquement acceptable de ces composés qui est métaboliquement labile, ou encore un sel pharmaceutiquement acceptable de ces composés, qu'on utilise comme antagonistes d'une ou de plusieurs actions du L-glutamate au niveau des récepteurs d'acides aminés excitateurs métabotropiques.