Catalytic Oxidative Coupling Reactions Based On Radical Processes

In the past few decades,Pd-catalyzed cross coupling reactions such as Stille reaction,Suzuki-Miyaura reaction and Heck reaction play an important role in the chemistry field.But pre-activation for the substrate not adapted to the development of green chemistry while using Pd-catalyst and phosphorus ligand.On the contrary,in recent years due to avoid pre-activation to the action,oxidative coupling reaction of free radical mechanism based on C-H functionalization have attracted more and more attention and made important progress.In this paper,through the domestic and foreign literature,several oxidative coupling reactions compared to the several kinds of typical free radical action upon he C-H functionalization in this paper.So we develop three types of C-H functionalization actions by means of oxidative coupling reaction:1 When using TBAI as catalyst and TBHP as the oxidant,we have achieved the oxidation coupling with amino pyridine and nitro styrene,we provides a simple method for the synthesis of economy of imidazo [1,2-a] pyridine derivatives for the first time.This method involves two amination actions directely.2 While employing sulfonyl hydrazide as sulfonyl radical precursors,the sulfonyl radical in the catalytic oxidation of KI-TBHP system realized cyclization reaction with N-aryl acrylamide free radical,and the reaction was carried out in the aqueous phase,the phase transfer achieved by adding 18-crown-6 to promote the reaction.Synthesis of sulfonyl substituted oxindole derivatives provides an environment friendly method.3 Based on the above research,the sulfonyl hydrazide generate the sulfonyl radical.Meanwhile using of TBAI-TBHP catalytic oxidation system,?,?-unsaturated imide radical take part into the cyclization reaction,and synthesis of isoquinoline-1,3(2H,4H)-two ketone derivatives.Through the research on the above three kinds of reactions,we developed the catalytic oxidation system utilizing cheap and nontoxic salt The system of(TBAI or KI)as catalyst,TBHP as a green oxidant bring about free radical mechanism in the C-H functionalization,and provides a simple and efficient method for synthesis of the heterocyclic compounds containing nitrogen.