Study Of Copper-catalyzed Construciton Of C-S And C-N Bonds

The transition-metal-catalyzed cross-coupling reactions are simple, efficient, andversatile routes to the formation of carbon-carbon and carbon-hetero bonds, whichrepresents the key step in a wide range of preparative organic processes. In lastdecades, many chemists mainly focused on design and synthesis of different kinds ofligands. However, study of more convenient and environment-friendly catalyticsystem is relatively rare. In comparison with Pd and Ni, copper is a cheap metal withlow-toxicity. In this thesis, we have investigated the copper-catalyzed C-S and C-Nbonds coupling reactions in novel reaction systems. The details are summarized asfollows:First, a simple and highly efficient catalytic system for synthesis of diarylSulfides by copper-catalyzed coupling of aryl halides and thioacetate in PEG-400/H2O media was developed. A variety of aryl halides could be reacted with thioacetateto give the desired products in high yields up to96%. The present catalysis protocoltolerated a wide scope of functional groups.Second, an efficient and convenient method for the synthesis of aryl hydrazinesis described via copper-catalyzed cross-coupling of aryl halides with aqueoushydrazine in PEG-400. This protocol is applicable to both electron-deficient andelectron-rich aryl iodides and bromides, and even to sterically hindered substrates,giving aryl hydrazines in good to excellent yields up to91%.Finally, we studied the copper-catalyzed reductive coupling reaction between theN-tosylhydrazones and2-mercaptobenzothiazole. We found that the correspondinglyaldehyde and ketone hydrazones are suitable substrates for this reductive C-S bondscoupling reaction.