Study On Nickel Catalyzed Hetero-Pauson-Khand Reaction Based On Isonitrile

The Pauson–Khand reaction?PKR?,a transition metal?such as cobalt,rhodium,palladium,molybdenum?catalyzed process for joining an alkene,an alkyne,and carbon monoxide to occur cyclic addition reaction,is a powerful tool for accessing cyclopentenone compounds.Isonitriles,as a kind of most commonly used stable carbon source,play an irreplaceable role over CO on participation in the Hetero-Pauson-Khand reaction?HPKR?.The use of isonitriles not only simplifies the reaction device,but also provides thieno[2,3,b]indole derivatives with good biology activities and potental applications in materials science.Although the traditional PKR has excellent atomic economy and good substrate applicability,there are also some limitations,such as the large loading of precious metal catalyst,the low yield,too harsh reaction conditions and so on.In the first chapter,the Hetero-Pauson-Khand?HPKR?reactions are generally reviewed.The summary of nickel catalyzed reactions in recent literature and the syntheses of heterocyclic compounds involved in isonitrile are also presented.In the second chapter,a Ni?acac?₂-catalyzed HPK reaction giving multi-substituted thieno[2,3,b]indole derivatives from an o-alkynyl isothiocyanate and isonitrile has been developed.The optimal reaction conditions were established by employing o-alkynyl isothiocyanate and isonitrile in a ratio of 1: 1.2 with a 0.3 mol% amount of Ni?acac?₂ stiring in 2-Me THF at 80 oC for how long.The results of substrate scope experiments showed that the method could tolerate a wide range of substrates with functional groups in good yields.Furthermore,the reaction mechanism was supported by GC-MS,TEM,XPS and Gaussian calculation of the possible intermediates.The method features simple operation,high yield,convenient processing,good atomic economy,on which no literature was reported previously.The structures of all the newly synthesized compounds were characterized by ¹H NMR,13 C NMR,and HRMS.Single crystals of compound 3a and 3s were cultured and their precise configurations were determined.