Studies On Cu-catalyzed C–C Bond Cleavage And Methodologies For The Synthesis Of 4-Quinolone Derivatives

This paper mainly discussed copper-catalyzed C–C bond cleavage and the method for the synthesis of 4-quinolone compounds.The research progresses on metal-involved unstrained C–C bond cleavage and the application and synthetic method of 4-quinolone derivatives.This paper included these five chapters:Chapter 1:Studies on unstrained C–C bond cleavage.C–C bonds are ubiquitous in organic compounds.Chemoselective cleavage of C–C bonds possess potential applications in organic synthesis and metal-mediated C–C bond cleavage has been shown to be a quite efficient process.This chapter mainly introduced the progress on metal-involved unstrained C–C bond cleavage in recent years.These methods provide new ideas for C–C bond activation.Chapter 2:Copper-catalyzed transformation of ketones to amides via C–C bond cleavage directed by pyridine.In this chapter,we introduced a chemoselective cleavage of C–C bond catalyzed by Cu?OAc?₂.N-?2-acetylphenyl?-picolinamide undergoes C–C bond cleavage with chelation assistance of pyridine and a new C–N bond is constructed,which transformed unactivated alkyl ketones into amides.In this procedure,sodium azide acts as the N source.This reaction provides a new strategy for C–C bond cleavage.Chapter 3:Studies on the application and synthetic method of 4-quinolone derivatives.4-quinolones are important nitrogen-containing heterocycles.In this chapter,we mainly described the significant role of quinolones in medicine,which can be used as antitumor agents,anxiolytic agents,anti-ischemic agents,antiviral chemotherapy,CB2 receptor agonists.We continued to introduce the representative methods for the synthesis of quinolones in recent years,which were divided into two categories:the first was metal-free-promoted synthesis of quinolones;the second was metal-catalyzed synthesis of quinolone.Chapter 4:Base-promoted cascade reaction to synthesize 3-benzyl-2-phenylquinolin-4?1H?-ones.In this chapter,we presented a novel and efficient one-pot route for the synthesis of 3-benzyl-2-phenylquinolin-4?1H?-one and its derivatives under transition-metal-free conditions.3-benzyl-2-phenylquinolin-4?1H?-one can be synthesized with N-?2-acetylphenyl?-picolinamide and benzaldehyde in good to excellent yield via cascade reaction under DBU and KHCO₃ conditions.The reaction intermediate was captured and a reasonable reaction mechanism was proposed for the reaction,which provided an efficient pathway for the synthesis of 3-benzyl-2-phenyl-4-quinolone compounds.Chapter 5:Metal-free oxidative intermolecular cyclization reaction:synthesis of 2-aryl-4-quinolones.In this chapter,we demonstrated the reaction of metal-free-promoted intermolecular cyclization to synthesize 2-aryl-4-quinolone compounds.Benzaldehydes and 2-amino-acetophenones efficiently converted to 2-aryl-4-quinolone compounds under TEMPO and KHCO₃reaction conditions.There was no need to add any metal catalyst in this reaction process and this procedure was atomic-economy.The avoidance of the preparation of substrates,fewer synthetic steps and using inexpensive materials provided a very practical method for the synthesis of 2-aryl-4-quinolone compounds.