Copper-catalyzed Three-component Domimo Reactions Of Azomethine Imines

Azomethine imines,as a class of typical 1,3-dipoles,have been extensively used in 1,3-DC reactions due to their ease of preparation and stability.Generally,azomethine imines can react with common dipolarophiles such as alkynes,alkenes catalyzed by copper to construct N,N-bicyclic pyrazolidinones derivatives which act as vital building blocks in numerous biologically active molecules and pharmaceuticals.Copper acetylides were proved to be the intermediates of the reaction.In this thesis,we have developed a facile way to synthesize N,N-bicyclic pyrazolidinone derivatives catalyzed by CuI and 2,2'-bipyridine through sequential 1,3-dipolar cycloaddition and umpolung thiolation by an electrophilic sulfenylating reagent with good yields.Three C-C,C-S,and C-N bonds were formed simultaneously in one pot.In the process,the pyrazolidinonate-Cu intermediate in situ generated from the cycloaddition of azomethine imine and cuprous acetylide participated in nucleophilic substitution with the electrophile sulfenylating reagent.It was the first example that the pyrazolidinonate-Cu intermediate had been captured by an electrophile other than H+.It would also offer an efficient protocol for the synthesis of functionalized pyrazolidinones.