Palladium-Catalyzed Coupling of Pyrazole Triflates with Arylboronic Acids
摘要:
A general protocol for the palladium-mediated Suzuki coupling reaction of pyrazole triflates and aryl boronic acids has been developed. The use of additional dppf ligand was determined to increase product yields allowing for the use of a broad range of reaction substrates.
Iron catalyzed oxidative assembly of N-heteroaryl and aryl metal reagents using oxygen as an oxidant
作者:Kun Ming Liu、Lian Yan Liao、Xin Fang Duan
DOI:10.1039/c4cc08494b
日期:——
An equivalent amount of N-heteroaryl and aryl Grignard or lithium reagents, after mediation by an equivalent of titanate, was facilely coupled to furnish N-heteroaryl-aryl compounds under the catalysis of FeCl3/TMEDA at ambient temperature usingoxygen as an oxidant. Most of the common N-heteroaryls were all good candidates, and thus provided a general, green and pratical protocol for the flexible
A highlyregioselectivesynthesis of 1-aryl-3,4,5-substituted pyrazoles based on the condensation of 1,3-diketones with arylhydrazines is described. The reaction proceeds at room temperature in N,N-dimethylacetamide and furnishes pyrazoles in 59-98% yields.
4-Substituted Hantzsch 1,4-dihydropyridines and 1,3,5-trisubstitutedpyrazolines were oxidized to the corresponding pyridines and pyrazoles, respectively, in high yields by molecular oxygen in the presence of catalytic amount of N-hydroxyphthalimide (NHPI) and Co(OAc)2 in acetonitrile at room temperature.
An unprecedented ruthenium(II)-catalyzed intramolecularoxidative C–N coupling method has been developed for the facile synthesis of a variety of synthetically challenging tri- and tetrasubstituted pyrazoles. Dioxygen gas is employed as the oxidant in this transformation. The reaction demonstrates excellent reactivity, functional group tolerance, and high yields.
A mild and efficient protocol for the synthesis of fluorinated pyrazoles has been developed via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor. This method offers a broad substrate scope.