Expedient access to branched allylic silanes by copper-catalysed allylic substitution of linear allylic halides
作者:Devendra J. Vyas、Martin Oestreich
DOI:10.1039/b920793g
日期:——
An unprecedented copper-catalysed allylic transposition enables the regioselectivesynthesis of branched allylic silanes from linear allylichalides through direct C-Si bond formation.
The first catalytic enantioselective allylic substitution reaction with alkylboron compounds has been achieved. The reaction between alkyl-9-BBN reagents and primary allylic chlorides proceeded with excellent γ-selectivities and high enantioselectivities under catalysis of a Cu(I)-DTBM-SEGPHOS system. The protocol produces terminal alkenes with an allylic stereogenic center branched with functionalized
We have presented full details of our work on alkylboranes, which we have introduced as new reagents for copper-catalyzed SN2′-type enantioselectiveallylicsubstitutions. The copper catalysis delivered enantioenriched chiral products containing tertiary or quaternarycarbonstereogeniccenters branched with functionalized sp3-alkyl groups. The wide availability of alkylboranes via the established
我们已经介绍了我们在烷基硼烷上的全部工作细节,我们已将其引入作为铜催化的S N 2'型对映选择性烯丙基取代的新试剂。铜催化递送了富含对映体的手性产物,该手性产物包含带有官能化的sp 3-烷基的叔碳或季碳立体异构中心。通过已建立的烯烃加氢硼化反应,烷基硼烷的广泛可用性是这些转化的吸引人的特征。基板中可以容忍各种官能团。提出了一种通过烯丙基氯底物加成-消除中性烷基铜(I)物种的反应途径。
Application of a Chiral Scaffolding Ligand in Catalytic Enantioselective Hydroformylation
作者:Amanda D. Worthy、Candice L. Joe、Thomas E. Lightburn、Kian L. Tan
DOI:10.1021/ja107433h
日期:2010.10.27
The synthesis of β-amino-aldehydes has been achieved throughenantioselective hydroformylation of PMP-protected allylic amines. The reaction is accomplished by using a scalemic scaffolding ligand that covalently and reversibly binds to the substrate. These ligands behave like chiral auxiliaries because they are covalently attached to the substrate during hydroformylation; however, similar to traditional
β-氨基醛的合成是通过 PMP 保护的烯丙胺的对映选择性加氢甲酰化来实现的。该反应是通过使用与底物共价可逆结合的鳞片支架配体来完成的。这些配体的行为类似于手性助剂,因为它们在加氢甲酰化过程中共价连接到底物上;然而,与传统的不对称配体类似,它们可以以催化量使用。二取代烯烃的直接加氢甲酰化在温和条件(35 °C 和 50 psi CO/H(2))下进行,Z-烯烃具有优异的对映选择性(高达 93% ee)。