Catalytic Metal-free Allylic C–H Amination of Terpenoids
作者:Wei Pin Teh、Derek C. Obenschain、Blaise M. Black、Forrest E. Michael
DOI:10.1021/jacs.0c06997
日期:2020.9.30
selective replacement of C-H bonds in complex molecules, especially natural products like terpenoids, is a highly efficient way to introduce new functionality and/or couple fragments. Here, we report the development of a new metal-free allylic amination of alkenes that allows the introduction of a widerange of nitrogen functionality at the allylic position of alkenes with unique regioselectivity and no
An efficient SbCl3-metal system for allylation, reduction and acetalization of aldehydes
作者:- Bo Wang Wei、Shi Li-Lan、Huang Yao-Zeng
DOI:10.1016/s0040-4020(01)85467-3
日期:1990.1
allylatlon of aldehydes with allylic halides at room temperature to give high yields of the corresponding homoallylic alcohols with high regio- and chemoselectivity. SbCl3-Al or SbCl3-Zn in DMF-H2O was found to be an efficient reduction system for conversion of aldehydes to alcohols at room temperature in excellent yields. While alcohol was used as solvent instead of DMF-H2o, the acetalization product was
Chloration allylique d'olefines de type isoprenique a l'aide du chlorure de sulfuryle
作者:Michel Bulliard、Geneviève Balme、Jacques Gore
DOI:10.1016/s0040-4039(00)76192-2
日期:1989.1
Sulfuryl chloride is a convenient reagent for the allylic chlorination of olefins bearing an isopropenyl or isopropylidenyl moeity. The substitution occurs with good yields and with allylic rearrangement, giving in most cases a secondary chloride.
Site-Selective Cu-Catalyzed Alkylation of α-Amino Acids and Peptides toward the Assembly of Quaternary Centers
作者:Marcos San Segundo、Arkaitz Correa
DOI:10.1002/cssc.201802216
日期:2018.11.23
The CuI‐catalyzed selective α‐alkylation of α‐amino acid and peptide derivatives with 2‐alkyl‐1,3‐dioxolanes is reported. This oxidative coupling is distinguished by its site‐specificity, high diastereoselectivity, and chirality preservation and exhibits absolute chemoselectivity for N‐aryl glycine motifs over other amino acid units. Collectively, the method allows for the assembly of challenging quaternary
Catalytic Cross-Metathesis Reactions That Afford <i>E</i>- and <i>Z</i>-Trisubstituted Alkenyl Bromides: Scope, Applications, and Mechanistic Insights
作者:Tobias Koengeter、Can Qin、Binh Khanh Mai、Qinghe Liu、Yucheng Mu、Peng Liu、Amir H. Hoveyda
DOI:10.1021/jacs.2c13289
日期:2023.2.15
(MAP) complexes, one purchasable and the other accessible by well-established protocols. Substrates, such as feedstock trisubstituted olefins, can be purchased; the alkenyl bromide reagents are commercially available or can be prepared in two steps in a multigram scale. The catalytic process can be used to generate products that contain polar moieties, such as an amine or an alcohol, or sterically hindered
末端具有溴化物和甲基的立体化学定义的三取代烯烃可以通过催化交叉偶联轻松地立体保留衍生,从而提供在许多生物活性天然产物中发现的不饱和片段。生成此类实体的直接方法是通过立体控制催化交叉复分解(CM)。然而,这样的方法很少。在这里,我们提出了三-、 Z-或E-二或单取代烯烃与Z-或E -2-溴-2-丁烯之间的CM立体保留策略,提供了各种E-或Z-三取代烯基溴。大多数转化是由两种钼单芳氧基吡咯烷 (MAP) 络合物催化,一种可购买,另一种可通过完善的方案获得。底物,例如原料三取代烯烃,可以购买;烯基溴试剂是可商购的或者可以以多克规模分两步制备。催化过程可用于生成含有极性部分的产物,例如胺或醇,或α-或β-支化的空间位阻烯烃。该方法的实用性通过 phomactin A 不饱和片段的简短立体控制合成和龙涎香的简明全合成得到强调。这些研究的一个意想不到的结果是发现了小分子烯烃在烯烃复分解反应中的新作用。