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。
primary allyl chlorides with enantiocontrol at a useful level. The reaction generates a stereogenic quaternary carbon center having three sp3‐alkylgroups and a vinyl group. This protocol allowed the use of terminal alkenes as nucleophile precursors, thus representing a formal reductive allylic cross‐coupling of terminal alkenes. A reaction pathway involving addition/elimination of a neutral alkylcopper(I)
原位生成的手性Cu I / DTBM-MeO-BIPHEP催化剂系统与EtOK的结合使烷基硼烷试剂与γ,γ-二取代的伯烯丙基氯之间的对映选择性S N 2'型烯丙基交叉偶联以及对映体控制有效等级。该反应产生具有三个sp 3-烷基和一个乙烯基的立体异构的季碳中心。该协议允许使用末端烯烃作为亲核试剂的前体,因此代表了末端烯烃的正式还原性烯丙基交叉偶联。提出了一种涉及用烯丙基氯底物添加/消除中性烷基铜(I)物质的反应途径。
Synthesis of Enantioenriched Tertiary Boronic Esters by the Lithiation/Borylation of Secondary Alkyl Benzoates
作者:Alexander P. Pulis、Daniel J. Blair、Eva Torres、Varinder K. Aggarwal
DOI:10.1021/ja409100y
日期:2013.10.30
range of neopentyl boronic esters which, after 1,2-metalate rearrangement and oxidation, gave a range of tertiaryalcohols in high yield and universally high er. Further functional group transformations of the tertiary boronic esters were demonstrated (conversion to quaternary centers, C-tertiary amines) together with application of the methodology to the synthesis of the simplest unbranched hydrocarbon
Metal-Catalyzed Ring-Opening of Alkylidenecyclopropanes: New Access to Building Blocks with an Acyclic Quaternary Stereogenic Center
作者:Samah Simaan、Alexander F. G. Goldberg、Stephane Rosset、Ilan Marek
DOI:10.1002/chem.200902656
日期:2010.1.18
Open sesame! A selective metal‐catalyzed ringopening of alkylidenecyclopropane derivatives leads to various functionalized acyclic derivatives possessing challenging quaternary stereocenters. The key feature of this transformation is that the ringopening is faster than the reductive elimination and is highly regioselective; a single ring‐opened product was always observed and the stereointegrity