Cyclotrimerization of terminal alkynes catalyzed by the system of NiCl2/Zn and (benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines
作者:Chanjuan Xi、Zelin Sun、Yongbing Liu
DOI:10.1039/c3dt51674a
日期:——
An effective regioselective cyclotrimerization of terminal alkynes is achieved by the direct utilization of NiCl2·6H2O, Zn, and 2-(benzimidazolyl)-6-(1-(arylimino)ethyl)pyridine in one step under ambient temperature.
Iron-Catalyzed Trimerization of Terminal Alkynes Enabled by Pyrimidinediimine Ligands: A Regioselective Method for the Synthesis of 1,3,5-Substituted Arenes
作者:Julianna S. Doll、Robert Eichelmann、Leif E. Hertwig、Thilo Bender、Vincenz J. Kohler、Eckhard Bill、Hubert Wadepohl、Dragoş-Adrian Roşca
DOI:10.1021/acscatal.1c00978
日期:2021.5.7
to a functional-group-tolerant methodology for the catalytic trimerization of terminal aliphatic alkynes. Remarkably, in contrast to established alkyne trimerization protocols, the 1,3,5-substituted arenes are the main reaction products. Preliminary mechanistic investigations suggest that the enhanced π-acidity of the pyrimidine ring, combined with the hemilability of the imine groups coordinated to
reactions by replacement of the traditional but environmentally disfavored organic solvents by water, we studied the cyclotrimerizations of alkynes, in aqueous microemulsions. The catalyst for these reactions was the rhodium-trichloride encaged within silica sol–gel. In acidic aqueous media, alkynes can undergo addition of water to form their corresponding ketones. In order to eliminate completely the formation
A Pd‐Au alloy efficiently catalyzed the [2+2+2] cycloaddition of substituted alkynes. Whereas monometallic Pd and Au catalysts were totally ineffective, Pd‐Au alloy nanoparticle catalysts with a low Pd/Au molar ratio showed high activity to give the corresponding polysubstituted arenes in high yields. A variety of substituted alkynes participated in various modes of cycloaddition under Pd‐Au alloy