The Cyanation Reactions Of Aromatic Halides And Diphenylacetylene With Formamide As Cyanide Source

Cyano is present in many natural products and synthetic substances,and it can be easily converted into other groups,such as carboxyl and acyl groups,so nitrile compounds occupy a very important position in the field of organic synthesis.The synthesis of nitrile compounds roughly goes through the following stages:In the first stage,hydrocyanic acid gas was directly used as the cyanogen source to achieve the synthesis of nitrile compounds under the reaction conditions of high temperature and high pressure as well as transition metal catalysis.In the subsequent research work,HCN gas was dissolved into liquid to avoid the high temperature and high pressure conditions,however,the problem of easy volatilization of hydrocyanic acid gas was not effectively improved,so that The use of HCN as cyanide source still has great potential hazards;in the second stage,scientists developed the use of some metal cyanide sources,such as KCN,Na CN,Cu CN,Ag CN,K₄[Fe（CN）₆],etc.,to achieve the synthesis of nitrile,although metal cyanide avoids the volatility of HCN gas and reduces the potential hazards during operation,however,the large amount of cyanide source remaining in the waste solution after the reaction is completed and metal waste can bring very great harm to human body and the environment;in the third stage,scientific researchers developed cyanide reactions with organic cyanide sources represented by low-toxic reagents such as TMSCN and HCONH₂.Compared with the first two stages,the use of organic cyanide sources further reduces the environmental hazards of cyanide sources,and the possibility of cyanide source poisoning during laboratory operations is greatly reduced.In the fourth stage,in recent years,chemists have explored some more green,non-toxic and lower cost combination cyanide sources,such as DMF/NH₄I,CO₂/NH₃ and other new combination cyanide sources,which are all renewable resources;instead,their cyanidation reactions as cyanide sources are not mature enough and need to be further studied.The research in this thesis consists of two main parts,both of which employ a strategy that uses Pd to catalyze the transfer of water from formamide to acetonitrile at a reaction temperature below 100 ^oC to produce a cyanogenic source.In the first part,the cyanation reaction of halogenated aromatics was achieved using the above strategy,and after a systematic screening and optimization of the conditions,the optimal reaction conditions were obtained:halogenated aromatics（0.2 mmol,1 equiv）,Pd（OAc）₂（15 mol%）,4,4’-di-tert-butyl-2,2’-bipyridine（5 mol%）,KOAc（2 equiv）,HCONH₂（1.0 m L）,acetonitrile（1.0 m L）,H₂O（0.10 m L）,80-100 ^oC,24 h.In the second part,the Pd/Rh co-catalytic hydrocyanation of diphenylacetylene was also achieved using the strategy of using Pd-catalyzed dehydration of formamide to produce a cyanogenic source,with the optimal reaction conditions:diphenylacetylene（0.2 mmol,1 equiv）,Pd Cl₂（20 mol%）,Rh Cl₃.3H₂O（7.5 mol%）,Xantphos（5 mol%）,Li OAc（3 equiv）,TACHF（30 mol%）,HCONH₂（0.5 m L）,acetonitrile（0.5 m L）,THF（0.25 m L）,95 ^oC,48 h.