Ionic‐Liquid‐Influenced Expeditious and Stereoselective Synthesis of Olefins
摘要:
1-Butyl-3-methylimidazolium chloroaluminate, [bmim] Cl center dot. AlCl3 (molar fraction, N = 0.67), ionic liquid has been used in combination with metallic Zn for the reductive coupling of carbonyl compounds to synthesize symmetrical olefins, with the Z-isomer formed predominantly. The ionic liquid played a dual role of Lewis acid catalyst and solvent.
Catalytic, Enantioselective <i>Syn</i>-Oxyamination of Alkenes
作者:Emily M. Mumford、Brett N. Hemric、Scott E. Denmark
DOI:10.1021/jacs.1c06750
日期:2021.8.25
2-oxyamination of alkenes using selenium(II/IV) catalysis with a chiral diselenide catalyst is reported. This method uses N-tosylamides to generate oxazoline products that are useful both as protected 1,2-amino alcohol motifs and as chiral ligands. The reaction proceeds in good yields with excellent enantio- and diastereoselectivity for a variety of alkenes and pendant functional groups such as sulfonamides
General Reaction Conditions for the Palladium-Catalyzed Vinylation of Aryl Chlorides with Potassium Alkenyltrifluoroborates
作者:Emilio Alacid、Carmen Nájera
DOI:10.1021/jo901681s
日期:2009.11.6
Activated and deactivated aryl and heteroaryl chlorides are efficiently cross-coupled with potassium vinyl- and alkenyltrifluoroborates using 4-hydroxyacetophenone oxime derived palladacycle as precatalyst in 1 to 3 mol % Pd loading, Binap as ligand, and Cs2CO3 as base in DMF at 120 °C. The reactions can also be performed using Pd(OAc)2 as Pd(0) source, although with lower efficiency. Bidentate ligands
活化和失活的芳基和杂芳基氯与乙烯基和链烯基三氟硼酸钾有效地交联,使用4-羟基苯乙酮肟肟衍生的palladacycle作为预催化剂,钯负载量为1-3 mol%,Binap作为配体,Cs 2 CO 3作为DMF中的碱120℃。尽管效率较低,但也可以使用Pd(OAc)2作为Pd(0)源进行反应。可以使用双齿配体,例如Binap和dppp,前者是最佳选择。仅在失活的芳基氯化物的情况下,才应将反应温度提高至160°C,以获得良好的收率。以高收率和高区域选择性和非对映选择性获得了相应的交叉偶联化合物,例如苯乙烯,对苯二甲酸酯和链烯基芳烃。
The Synthesis of a Combretastatin A-4 Based Library and Discovery of New Cooperative <i>ortho</i>-Effects in Wittig Reactions Leading to (<i>Z</i>)-Stilbenes
A synthesis of combretastatin A-4 and a small library of analogues led to the discovery of some new cooperative ortho-effects allowing (Z)-stilbenes to be prepared in high yield and diastereomeric ratio.
Flavin-Mediated Photocatalysis Provides a General Platform for Sulfide C–H Functionalization
作者:Alex S. Anderton、Oliver J. Knowles、James A. Rossi-Ashton、David J. Procter
DOI:10.1021/acscatal.3c05785
日期:2024.2.16
Functionalized sulfides are important in many areas of science, ranging from chemical biology through drug discovery to organic materials chemistry. Sulfides bearing pendant reactive groups in the α-position are particularly useful; however, methods for the selective valorization of simple sulfides or the late-stage functionalization of complex sulfides by the convenient addition of valuable functionality