cyclopentane/[PdCl(C3H5)]2 efficiently catalyses the Heck reaction of disubstituted alkenes such as methyl crotonate, ethyl cinnamate, methyl methacrylate or α-methylstyrene with a variety of aryl halides. In the presence of 1,2-disubstituted alkenes the stereoselectivities of the reactions strongly depend on the substituents of the alkenes. Selectivities up to 97% in favor of E-isomers can be obtained
顺式,顺式,顺式-1,2,3,4-四(二苯基膦甲基)环戊烷/ [PdCl(C 3 H 5)] 2有效催化巴豆酸甲酯,肉桂酸乙酯,甲基丙烯酸甲酯或α等二取代烯烃的Heck反应-甲基苯乙烯与各种芳基卤化物。在1,2-二取代的烯烃的存在下,反应的立体选择性强烈取决于烯烃的取代基。添加到巴豆酸甲酯中可以得到高达97%的选择性,有利于E-异构体。用1,1-二取代的烯烃获得甲基丙烯酸甲酯或α-甲基苯乙烯的产物混合物。
1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
作者:Courtney C. Aldrich、Joseph A. Buonomo、Malcolm S. Cole、Carter G. Eiden
DOI:10.1055/s-0040-1707345
日期:2020.12
variants of the Wittig olefination, Appel halogenation, and Staudingerreduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalyticStaudingerreductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters
The [RPPh3]2[Pd2X6] as a Catalyst Precursor for the Heck Cross-Coupling Reaction by in situ Formation of Stabilized Pd(0) Nanoparticles
作者:Abdol Hajipour、Ghobad Azizi
DOI:10.1055/s-0032-1317963
日期:——
Pd(II) anionic, square planar complexes of the type [RPPh3](2)[Pd2X2Cl4], where X = Cl, Br, have been applied for the first time as a catalyst precursor for the Heck reaction carried out in DMF at 140 degrees C. The highest yield was obtained for the most reducible ones, [MePPh3](2)[Pd2Br2Cl4], in DMF in the presence of NaHCO3 as a base. It was found that during the reaction, phosphonium halide stabilized Pd(0) nanoparticles of about 10 nm, which have been formed in situ from the palladium(II) precursor and Pd(0) colloidal nanoparticles acts as the reservoir for Pd(II) species via activation of the metal surface through the oxidative addition of aryl halides.
On the regiospecificity of the sulfoxide elimination
作者:B.M. Trost、K K. Leung
DOI:10.1016/s0040-4039(00)91147-x
日期:——
Silica-acetylacetone-supported palladium nanoparticles as an efficient and reusable catalyst in the Heck-Mizoroki C-C cross-coupling reaction
The preparation of palladiumnanoparticlessupported on acetylacetone‐modified silica gel and their catalytic application for Heck olefination of aryl halides were investigated. The catalyst was characterized using X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission and scanning electron microscopies. The supportedpalladiumnanoparticles are demonstrated to be a highly active and