Studies On The Cross Coupling Reactions Of Diazo Compounds

In organic synthesis chemistry,diazo compounds are usually used as highly reactive and multifunctional reagents,which play important roles in a wide range of conversions.As a results,it has been attracted widespread attentions and studied by a great deal of organic chemists.In general,because of the different groups connected to diazo groups,different kinds of diazo compounds often show different reaction activities,which greatly enriches the reaction diversity of these compounds.For example,cyclization reaction,electrophilic reaction,nucleophilic reaction and various reactions involving carbene formed with transition metals.Although the reactions involving diazo compounds have been developed and studied for a long time,research on the reactions involving these compounds have never stopped,and an increasing number of reactions have been discovered,which play an important role in the construction of C-X bonds,and many valuable organic compounds have been synthesized.Based on the reasons as mentioned above and our group research interests,in this paper,diazo compounds were used as raw materials to explore the novel cross coupling reactions with different substrates.The research findings are showed as follows:Part one:Interception of perfluoroalkylsulfinyloxy radical by copper-based carbene generated in situ has been developed.In this reaction,inexpensive copper acetate was used as catalyst,α-diazo carbonyl compounds and sodium perfluoroalkylsulfinate(CnF2n+1SO2Na)with different carbons were used as reaction substrates,tert-butyl hydroperoxide was used as oxidant,which could deliver the perfluoroalkanesulfinate ester rapidly under mild reaction conditions.In the mechanism studies,by trapping the trifluoromethyl radical species,this result indicated that perfluoroalkylsulfinyloxy radical was generated in situ in this process,and then it was rapidly trapped by the copper-based carbenes,followed by the protonation process to get the desired target product,and one C-O bond was formed.This new reaction provides a novel mode for the reaction of radicals with transition-metal carbenes,which is conductive to develop the more cross coupling reactions based on radicals and carbenes.Part two:we have developed a silver-catalyzed cross coupling reaction of diazo compounds and sodium arylsulfinate to afford a series of P-carbonyl arylsulfones in moderate to high yields.More importantly,this reaction is easy to gram scale synthesis,which can deliver the corresponding product in good yield,providing a foundation for practical application.The sulfonyl radical and silver-based carbene were confirmed to be generated in this reaction system through mechanism verification experiments,which can undergo cross coupling reaction in this system,and then the water provides a proton,the desired product was obtained by protonlysis.At the same time,the C-S bond was constructed in this process.Accessible raw materials,excellent substrates compatibility,mild reaction conditions and simple manipulation are advantages of this novel transformation.Part three:The oxidative coupling of diazo compounds and ammonium iodide(NH4I)was developed to provide the primary oxamates and primary α-ketoamides under transition metal free conditions.In this reaction,the diazoesters and α-diaoketones were used as different substrate to couple with the ammonium iodide(NH4I),and a varity of primary oxamates and primary α-ketoamides were provided in moderate to good yields.The mechanism studies show that there are two possible pathways for this reaction.The advantages of this reaction are wide substrate scopes,excellent functional group compatibility,mild reaction conditions and operational simplicity.In addition,this process simultaneously constructs one C-N bond and one C=O bond in one-pot.