N-Picolinamides as ligands in Ullman type C–O coupling reactions

Electrochemical-induced hydroxylation of aryl halides in the presence of Et3N in water

A thorough study of mild and environmentally friendly electrochemical-induced hydroxylation of aryl halides without a catalyst is presented. The best protocol consists of hydroxylation of different aryl iodides and aryl bromides by water solution in the presence of Et3N under air, affording the target phenols in good isolated yields. Moreover, aryl chlorides were successfully employed as substrates. This methodology also provides a direct pathway for the formation of deoxyphomalone, which displayed a significant anti-proliferation effect.

An advancement in the synthesis of nano Pd@magnetic amine-Functionalized UiO-66-NH2 catalyst for cyanation and O-arylation reactions

The magnetic MOF-based catalytic system has been reported here to be an efficient catalyst for synthesis of benzonitriles and diarylethers of aryl halides under optimal conditions. The MOF catalyst was built based on magnetic nanoparticles and UiO-66-NH₂ which further modified with 2,4,6-trichloro-1,3,5-triazine and 5-phenyl tetrazole at the same time and the catalyst structure was confirmed by various techniques. This new modification has been applied to increase anchoring palladium into the support. Furthermore, the products' yields were obtained in good to excellent for all reactions under mild conditions which result from superior activity of the synthesized heterogeneous catalyst containing palladium. Also, the magnetic property of the MOF-based catalyst makes it easy to separate from reaction mediums and reuse in the next runs.

Recent Advancement of Ullmann Condensation Coupling Reaction in the Formation of Aryl-Oxygen (C-O) Bonding by Copper-Mediated Catalyst

Transition metal-catalyzed chemical transformation of organic electrophiles and organometallic reagents belong to the most important cross coupling reaction in organic synthesis. The biaryl ether division is not only popular in natural products and synthetic pharmaceuticals but also widely found in many pesticides, polymers, and ligands. Copper catalyst has received great attention owing to the low toxicity and low cost. However, traditional Ullmann-type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of homogeneous copper catalyst with presence of bidentate ligands over the past two decades has totally changed this situation as these ligands enable the reaction promoted in mild condition. The reaction scope has also been greatly expanded, rendering this copper-based cross-coupling attractive for both academia and industry. In this review, we will highlight the latest progress in the development of useful homogeneous copper catalyst with presence of ligand and heterogeneous copper catalyst in Ullmann type C-O cross-coupling reaction. Additionally, the application of Ullmann type C-O cross coupling reaction will be discussed.