Studies On Pd-Catalyzed Carboamination Of Alkenyl Hydrazones

Pyridazines and tetrahydropyridazines are an important structural units occurring in some natural products and play important roles in a large number of biologically active molecules and pharmaceuticals such as influenza neuraminidase inhibitor and nonsteroidal progesterone receptor.Pyrazine and its derivatives are considered one of the most promising heterocyclic frameworks in small molecule drug design.Methods for the synthesis of Pyrazine and its derivatives are also being explored,such as hydrogenations,nucleophilic addition reactions,radical reactions and rearrangement reactions.But these methods still have some limitations,therefore,the development of efficient protocols to expand synthetic avenues for pyrazine and its derivatives is highly urgent.We report herein a facile approach synthesize to tetrahydropyridazines efficiently via Pd-catalyzed carboamination of readily available alkenyl hydrazones with aryl and alkenyl halides.Compared with the traditional method of synthesizing pyridazine and its derivatives,this method has the advantages of simple operation and wide application range of substrates.Preliminary studies showed the promise of this chemistry for enantioselective synthesis,which paved the way for the development of catalytic asymmetric versions..This work offers an expedient access to tetrahydropyridazine scaffold bearing a multitude of substitution patterns,thus significantly increased the availability of these derivatives for downstream evaluation.