N-heterocyclic carbene (NHC)-modulated Pd/Cu cocatalyzed three-component synthesis of 2,6-diarylquinolines
作者:Chen Xu、Hong-Mei Li、Xiao-Er Yuan、Zhi-Qiang Xiao、Zhi-Qiang Wang、Wei-Jun Fu、Bao-Ming Ji、Xin-Qi Hao、Mao-Ping Song
DOI:10.1039/c4ob00231h
日期:——
An efficient NHC-modulated Pd/Cu cocatalyzed three-component coupling reaction for the synthesis of 2,6-diarylquinolinesviaoxidation, cyclization and Suzuki reactions.
Stereoelectronic Effects Characterizing Nucleophilic Carbene Ligands Bound to the Cp*RuCl (Cp* = η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>) Moiety: A Structural and Thermochemical Investigation
作者:Jinkun Huang、Hans-Jörg Schanz、Edwin D. Stevens、Steven P. Nolan
DOI:10.1021/om990054l
日期:1999.6.1
The reaction of [Cp*RuCl](4) (1) with carbene ligands affords unsaturated Cp*Ru(L)Cl [Cp* = eta(5)-C5Me5; L = 1,3-R-2-imidazol-2-ylidene [R = cyclohexyl (ICy, 2); 4-methylphenyl (ITol, 3); 4-chlorophenyl (IpCl, 4); adamantyl (IAd, 5)] and 4,5-dichloro-1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMesCl, 6)] complexes 2-6 in high yield. Solution calorimetric investigations of this series provides a measure of the electron donor properties of all ligands, and comparisons are made with IMes [1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene] and the widely used PCy3. Structural information from single X-ray studies for complexes 2, 3, 5, 6, Cp*Ru(IMes)Cl (7), Cp*Ru(PCy3)Cl (8), and Cp*Ru((PPr3)-Pr-i)Cl (9) permits a quantitative treatment of steric parameters associated with these Ligands.