Study On The Ullmann Reaction

Ullmann reaction is an effective way to form C-C bond, C-N bond, C-O bond, C-S bond in organic synthesis, but it has still some limitations due to the harsh reaction conditions. Thus in this thesis, we improved the Ullmann reaction conditions and expanded the scopes of its application in organic synthesis, the main contents are as following:1. Pd(OAc)₂/NHC complex was successfully applied into palladium-catalyzed cyanation of bromobenzene, and the present catalyst displayed high catalytic activity in the optimum conditions. It was realized that the traditional organic phosphine ligands were replaced by the new ligand of N-heterocyclic carbene.2. i-Propanol was found to have a remarkable ability to protect the Pd-catalyzed cyanation from being destroyed by oxygen. By the addition of i-propanol, the reaction was allowed to be fully exposed to air, and the cyanations of some aryl iodides with a variety of functional groups gave high yields in 0.4-5 hours.3. We have developed a simple and easy-handling procedure for copper-catalyzed cyanation of aryl halides using K4[Fe(CN)₆] as the cyanide source. The present procedure has ligand- and base-free advantages, and was accomplished under the conditions of exposure to the air without degassing of the solvent.4. We carried out the selective control of preparation for phenyl ether and phenol from iodobenzene with 10 mol% of Cu(OAc)₂·H₂O as the catalyst under the condition of exposure to air. Phenyl ether was directly prepared from iodobenzene in the organic solvent of NMP, and phenol was directly prepared from iodobenzene in water. .