The Synthesisofheterocyclic Compound By Oxidative Coupling Reactions Using Transition Metal Complex Catalysts

Heterocyclic compounds have been paid high attention by chemists because of their good biologicalactivities and pharmacological properties. As a result, many chemical scientists have made some greatefforts in the development of new efficient synthesis approach to heterocyclic compounds. In all kinds ofsynthesis methods, transition metal catalyzed oxidative coupling reaction becomes one of the mostattractive methods to form C-O, C-N. Here in, on the basis of the existing synthetic routes, we studied thesynthesis of heterocyclic compounds with transition-metal catalyzed oxidative coupling reaction as astarting point, the innovation achievements are as follows:1. The synthese of imidazoline ketone by copper catalytic oxidative couplingIn traditional transition-metal catalyzed oxidative coupling reaction, the expensive, scarce and toxicmetal catalysts such as palladiumrhodium, iridium and gold are most used. Considering the sustainabilityand environmental standards, it is important in practical application to use the rich, cheap and non-toxiccopper as a transition metal catalyst in catalytic synthesis. Here, we report a novel and efficient coppercatalyzed direct tandem [3+2] cycloaddition/oxidation reaction from pyridines/isoquinoline, chalcones,ethyl chloroacetate and molecular oxygen under mild conditions with an efficient performance. Andmolecular oxygen is an ideal and green oxidant for catalytic chemistry. The direct utilization of molecularoxygen for the construction of valuable nitrogen-containing organic compounds is of great interest in bothacademic and industrial communities due to its economic and environmentally benign features.2. The synthese of furans by Manganese dioxide mediated to promote coupling reactionThe direct conjugate addition reaction of, β-unsaturated carbonyl compounds is mainly used in thesynthesis of pharmaceutical and natural products, and furans are valuable synthetic building blocks foragrochemicals and active pharmaceutical ingredients; thus, it is crucial to explore the synthesis methods offurans by transition metal catalytic oxidation of,β-unsaturated carbonyl compounds. Consideringsustainability and environmental criteria, economically and environmentally benign manganese complexesare attractive because manganese is one of the most relevant goals in chemistry and catalysis. So, with theoptimized conditions in hand, we explored the synthesis of3,4-dicarbonyl substitutedfurans from 1,3-dicarbonyl compounds and the, β-unsaturated carbonyl compounds via the fracture of C-H, C=O andthe formation of C=C, C-O, using manganese dioxide and zinc chloride as the composite catalyst system,and gave a high yield. The synthesis of3,4-dicarbonyl furan compounds using simple substrates in onestep, these features demonstratea current methodology that also point out a way forward to develop a directoxidative coupling reaction of other furans.