Olefin‐Supported Cationic Copper Catalysts for Photochemical Synthesis of Structurally Complex Cyclobutanes
作者:Christopher S. Gravatt、Luis Melecio‐Zambrano、Tehshik P. Yoon
DOI:10.1002/anie.202013067
日期:2021.2.19
The sole method available for the photocycloaddition of unconjugated aliphatic alkenes is the Cu‐catalyzed Salomon–Kochi reaction. The [Cu(OTf)]2⋅benzene catalyst that has been standard in this reaction for many decades, however, is air‐sensitive, prone to photodecomposition, and poorly reactive towards sterically bulky alkene substrates. Using bench‐stable precursors, an improved catalyst system with
可用于非共轭脂肪烯烃光环加成的唯一方法是铜催化的 Salomon-Kochi 反应。然而,几十年来一直是该反应标准的[Cu(OTf)] 2 ·苯催化剂对空气敏感,易于光分解,并且对空间庞大的烯烃底物反应性差。使用台式稳定的前体,设计了一种具有优异反应性和光稳定性的改进催化剂体系,并显着扩大了底物范围。通过制备天然产物 sulcatine G 和 perforatol 的核心,突出了这种新催化剂用于制备空间拥挤环丁烷结构的实用性。
The activity of covalently immobilized Grubbs–Hoveyda type catalyst is highly dependent on the nature of the support material
A Hoveyda-type catalyst for olefinmetathesis was synthesized and covalently attached via an amide bond to four different solid supports. One of these supports was a home-made hybrid silica support, where an ultra-thin copolymer of poly(styrene) and poly(acrylamide) was grafted on. The three other supports were commercially available, namely HypoGel 400, PEGA and Trisoperl. It was demonstrated that
Application of aGrubbs–Hoveyda Metathesis Catalyst Noncovalently Immobilized by Fluorous–Fluorous Interactions
作者:Florian Michalek、Willi Bannwarth
DOI:10.1002/hlca.200690080
日期:2006.5
A Grubbs–Hoveyda metathesiscatalyst bearing a tris(perfluoroalkyl)silyl tag for efficient noncovalent attachment to fluorous silica gel (FSG) was synthesized and employed in ring-closing metathesis (RCM) reactions in CH2Cl2. After the reaction, a solvent switch to a polar system allowed for recovery of the catalyst by filtration and its reuse. The approach was demonstrated for a number of different