Nickel-catalyzed cycloisomerization of enynes: catalyst generation via C–H activation of carbene ligands
作者:Thomas N. Tekavec、Janis Louie
DOI:10.1016/j.tet.2008.03.071
日期:2008.7
The combination of Ni(0) and an N-heterocyclic carbene acts as a precatalyst for the cycloisomerization of enynes to afford 1,3-dienes. During the course of the reaction, a nickel hydride is formed from oxidative addition of the ortho C-H on the carbene ligand. Deuterium labeling studies are presented. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.
A Sterically Bulky Cyclic Thiourea as an Efficient Ligand for Palladium-Catalyzed Aerobic Oxidation of Alcohols
Sterically bulky N,N¢-disubstituted cyclic thiourea ligand L1 has been demonstrated as an efficient ligand in palladium-catalyzed oxidation of alcohols using molecular oxygen as an oxidant. This new catalyst system has been applied to a wide variety of substrates such as benzylic alcohols, aliphatic secondary alcohols and allylic alcohols, producing the corresponding carbonyl compounds in good to excellent yields.
Sterically Bulky Thioureas as Air- and Moisture-Stable Ligands for Pd-Catalyzed Heck Reactions of Aryl Halides
作者:Dan Yang、Ying-Chun Chen、Nian-Yong Zhu
DOI:10.1021/ol049697+
日期:2004.5.1
We demonstrate that sterically bulky N,N'-disubstituted cyclic thiourea-Pd(0) complexes are air- and moisture-stable and highly active catalysts for palladium-catalyzed Heck reaction of aryl iodides and bromides with olefins (TONs up to 500000 for the reaction of PhI and methyl acrylate). Even activated arylchlorides can undergo complete conversion in Bu(4)NBr in the presence of 1 mol % Pd catalyst