improved generation of chiral cationic iridium catalysts for the asymmetricisomerization of primaryallylicalcohols is disclosed. The design of these air‐stable complexes relied on the preliminary mechanistic information available, and on Charton analyses using two preceding generations of iridium catalysts developed for this highly challenging transformation. Sterically unbiased chiral aldehydes
Copper(<scp>i</scp>)-catalysed asymmetric allylic reductions with hydrosilanes
作者:T. N. Thanh Nguyen、Niklas O. Thiel、Johannes F. Teichert
DOI:10.1039/c7cc07008j
日期:——
copper(I)-catalysed asymmetric allylic reduction enables a regio- and stereoselective transfer of a hydride nucleophile in an SN2′-fashion onto allylic bromides. This transformation represents a conceptually orthogonal approach to allylic substitution reactions with carbon nucleophiles. A copper(I) complex based upon a chiral N-heterocyclic carbene (NHC) ligand allows for stereoselectivity reaching 99% ee
铜(I)催化的不对称烯丙基还原可实现S N 2'形式的氢化物亲核试剂的区域和立体选择性转移到烯丙基溴上。这种转变代表了与碳亲核试剂进行烯丙基取代反应的概念上正交的方法。基于手性N-杂环卡宾(NHC)配体的铜(I)配合物可使立体选择性达到99%ee。不管起始材料的双键构型如何,该催化剂都能进行立体收敛反应。
Stereoselective Coupling Reaction of (2Z)-β-Arylselenocinnamic Esters with Grignard Reagents in Presence of CuI
作者:Xian Huang、Chang-Qiu Zhao
DOI:10.1080/00397919708007069
日期:1997.10.1
Abstract Stereoselective synthesis of trisubstituted alkenes linked with ester groups via coupling reaction of (2Z)-β-arylselenocinnamic esters with Grignardreagents in presence of equal molar quantities of CuI was reported.
摘要 报道了在等摩尔量的 CuI 存在下,通过 (2Z)-β-芳基硒肉桂酸酯与格氏试剂的偶联反应,立体选择性合成与酯基连接的三取代烯烃。
Stereoselecive Synthesis of 3-Alkylcinnamic Esters <i>via</i> Coupling Reaction of (2Z)-3-(Aryltelluro)cinnamic Esters in Presence of CuI
作者:Xian Huang、Chang-Qiu Zhao
DOI:10.1080/00397919708005023
日期:1997.1
Abstract Coupling reaction of (2Z)-3-(aryltelluro) cinnamic esters with Grignardreagents in presence of CuI produced trisubstituted alkenes containing ester groups with retention of configuration.
Palladium-Catalyzed Arylation of Enoates with Iodobenzene: Stereoselective Synthesis of Trisubstituted Olefins
作者:Talita de A. Fernandes、Boniek G. Vaz、Alcides J. M. da Silva、Pierre M. Esteves、Marcos N. Eberlin、Paulo R. R. Costa
DOI:10.5935/0103-5053.20130067
日期:——
The Heck reaction between E- and Z-enoates and iodobenzene was studied in the presence of Pd(OAc)(2). The stereochemistry in resulting adducts was dependent on the enoate geometry (stereospecific reaction). Best yields were obtained from Z-isomers in acetone using Ag2CO3 as base. The main cationic palladium intermediates possibly involved in the catalytic cycle could be intercepted and characterized by electrospray ionization mass spectrometry (ESI-MS). The stereoselectivity observed was rationalized through the classic mechanism of the Heck reaction.