Catalyst for aromatic C—O, C—N, and C—C bond formation
申请人:Yale University
公开号:US06562989B2
公开(公告)日:2003-05-13
The present invention is directed to a transition metal catalyst, comprising a Group 8 metal and a ligand having the structure
wherein R, R′ and R″ are organic groups having 1-15 carbon atoms, n=1-5, and m=0-4. The present invention is also directed to a method of forming a compound having an aromatic or vinylic carbon-oxygen, carbon-nitrogen, or carbon-carbon bond using the above catalyst. The catalyst and the method of using the catalyst are advantageous in preparation of compounds under mild conditions of approximately room temperature and pressure.
Palladium-Catalyzed Arylation of Malonates and Cyanoesters Using Sterically Hindered Trialkyl- and Ferrocenyldialkylphosphine Ligands
作者:Neil A. Beare、John F. Hartwig
DOI:10.1021/jo016226h
日期:2002.1.1
diethyl malonate, di-tert-butyl malonate, diethyl fluoromalonate, ethyl cyanoacetate, and ethyl phenylcyanoacetate. Although alkyl malonates and ethyl alkylcyanoacetates did not react with aryl halides using these catalysts, the same products were formed conveniently in one pot from diethylmalonate by cross-coupling of an aryl halide in the presence of excess base and subsequent alkylation.
We report here an operationally simple protocol for the direct aromatic perfluoroalkylation and trifluoromethylation of α‐cyano arylacetates. This metal‐free approach, which occurs at ambient temperature and under visible‐light irradiation, is driven by the photochemical activity of electron donor–acceptor (EDA) complexes, formed in situ by the interaction of transiently generated enolates and perfluoroalkyl
In the presence of catalytic amounts of
Pd
2
(dba)
3
·CHCl
3
and dppb, the
reaction of pronucleophiles 1 with vinyltins 2 gives the corresponding
alkylative dimerization products of the vinyl group, 1,4-disubstituted
butene derivatives 3, in good to high yields.
Role of base in palladium-catalyzed arylation of carbanions
作者:Anton V Mitin、Alexander N Kashin、Irina P Beletskaya
DOI:10.1016/j.jorganchem.2003.12.039
日期:2004.3
proposed a novel mechanism of palladium-catalyzed arylation of CH-acids. The main feature of this mechanism is the accelaration of the reductive elimination due to the deprotonation of the intermediate ArPdL2CHXY. The correlation between the carbanion reactivity and the pKa values for related CH-acids as well as the ligand effect are discussed in the framework of the proposed mechanism.
某些砜,氰基乙酸酯和丙二腈衍生的碳负离子与芳基溴化物的芳基化反应(使用Pd 2 dba 3 / 3L的催化体系,L = PPh 3,P t Bu 3)以及碳负离子的反应一当量的4-CF 3 C 6 H 4 Pd(PPh 3)2溴已被研究。只要反应混合物中存在比初始碳负离子强的碱,这些反应就可以顺利进行。在没有上述类型的碱的情况下,反应根本不进行。考虑到这一点,我们提出了钯催化CH-酸芳基化的新机制。该机理的主要特征是由于中间ArPdL 2 CHXY的去质子化而加速了还原消除。在所提出的机理的框架内,讨论了碳负离子反应性和相关CH-酸的p K a值之间的相关性以及配体效应。