使用新的 (PCN)Ir 配合物作为预催化剂和t BuNH 2作为助催化剂,开发了以乙醇为氢源的 1,3-烯炔的反式半氢化反应。该催化剂体系以高产率和立体选择性提供了一种高效且原子经济地获得不对称 ( E , E )-1,4-二芳基丁二烯的途径。监测过程显示,1,3-烯炔的三键顺式半氢化(形成 ( E , Z )-丁二烯)和 ( E , Z ) 到-( E , E ) 异构化形成( , _E )-丁二烯。
A 1,4‐Palladium Migration/Heck Sequence with Unactivated Alkenes: Stereoselective Synthesis of Trisubstituted 1,3‐Dienes
作者:Ze‐Jian Xue、Meng‐Yao Li、Bin‐Bin Zhu、Zhi‐Tao He、Chen‐Guo Feng、Guo‐Qiang Lin
DOI:10.1002/adsc.202001589
日期:2021.4.13
The palladium‐catalyzedcross‐coupling of ortho‐vinyl aromatic bromides and olefins was achieved through a controllable 1,4‐palladium migration/Heck cascade protocol. The reaction represents a mild, efficient and highly stereoselective method for the synthesis of trisubstituted 1,3‐dienes, especially for triaryl‐substituted ones.
Catalytic Reactions of Carbene Precursors on Bulk Gold Metal
作者:Yibo Zhou、Brian G. Trewyn、Robert J. Angelici、L. Keith Woo
DOI:10.1021/ja900653s
日期:2009.8.26
Bulk gold metal powder, consisting of particles (5-50 microm) much larger than nanoparticles, catalyzes the coupling of carbenes generated from diazoalkanes (R(2)C=N(2)) and 3,3-diphenylcyclopropene (DPCP) to form olefins. It also catalyzes cyclopropanationreactions of these carbeneprecursors with styrenes. The catalytic activity of the gold powder depends on the nature of the gold particles, as
散装金金属粉末,由比纳米粒子大得多的粒子 (5-50 微米) 组成,催化重氮烷烃 (R(2)C=N(2)) 和 3,3-二苯基环丙烯 (DPCP) 产生的卡宾的耦合形成烯烃。它还催化这些卡宾前体与苯乙烯的环丙烷化反应。金粉的催化活性取决于金颗粒的性质,这由 TEM 和 SEM 研究确定。可以从涉及生成卡宾 R(2)C:吸附在金表面上的中间体的机制来理解这些反应。