Studies On Base Promoted Carbon-Nitrogen Bonds Activation And Transformation Of Benzyl Quaternary Ammonium Salt

Amines that contain carbon-nitrogen bond（C-N）are exist widely in nature.They can be converted into high-quality nitrogen sources or carbon sources through C-N bond activation in organic synthesis,biomedicine,industrial production and other fields.Due to the high dissociation energy of inert C-N bond,it is difficult for organic amine compounds to be converted through C-N bond activation.At present,they are mainly two ways for C-N bonds conversion:i)transition-metal catalyzed direct insertion of inert C-N bonds,and ii)convert inert C-N bonds into highly active nitrogen compounds for reactivation.As for transition metals,the use of expensive transition metal catalysts and ligands increases the cost of reaction.Transition metals tend to be coordinate with products that contain lone pair electrons,resulting in the products being easily contaminated by metals.However,converting the inert C-N bond compound into organic quaternary ammonium salt with active C-N bond and then activating it can enhance the reaction activity and reduce the difficulty of reaction.Organic benzyl quaternary ammonium salt can be prepared from a variety of fatty amines and aromatic amines through a simple salting reaction.It has stable properties,long-term storage,low toxicity and high reactivity.Based on this,this paper mainly explores the construction of C-C bonds and C=C bonds by the activation of C-N bonds promoted by bases.The specific research contents and results are as follows.1.The base promotes the reaction of benzyl C（sp³）-H compound with benzyl quaternary ammonium salt to construct C-C bond by breaking C-N bond.With the promotion of base,benzyl quaternary ammonium salts react with benzyl C（sp³）-H compounds as electrophiles to obtain a series of conjugate products with good to excellent yields.With the promotion of base,benzyl quaternary ammonium salts react with benzyl C（sp³）-H compounds as electrophiles to obtain a series of conjugate products with good to excellent yields.Benzyl C（sp³）-H compounds such as esters,amides,nitriles and phosphine oxide can react well with benzyl quaternary ammonium salts.The activity of benzyl quaternary ammonium salts containing other anions was investigated.The yields of benzyl quaternary ammonium salts containing other anions were 91%to 99%.Gram synthesis and dehydrogenation of products with specific 1,2-diarylethane structure to olefin compounds have proved that the reaction has great application value.2.The alkalization of benzyl quaternary ammonium salt with sulfone is facilitated by the activation of C-N bond cleavage to construct the C=C bond.A series of E selective stilbene and related 1,3-diene derivatives are obtained by the enylation of benzyl quaternary ammonium salt as electrophilic reagent with sulfone in the promotion of base.The reaction condition is mild,no transition metal catalysis is required,and the compatibility of various functional groups is good.The reaction mechanism is as follows:benzyl sulfone deprotonates in the presence of a base to form an anionic intermediate,which undergoes nucleophilic substitution with benzyl quaternary ammonium salt,and then removes trimethylamine（NMe₃）and OTf-.Finally,the target product is obtained by elimination reaction.Gram amplification synthesis and successful synthesis of resveratrol and DMU-212 compounds with significant biological activities indicated the application value of this reaction.