Studies On The Synthesis Of Propargylamines And Diarylmethyl Phosphine Oxides Via The Cleavage Of Sp~3C-N Bonds

The C-N bond is one type of the most common chemical bonds,and has high dissociation energy.It is of great significance to construct complex functional compounds by C-N bond cleavage.A variety of transition metal-catalyzed reactions for constructing new C-Z bonds via cleavage of the C-N bonds of simple nitrogen-containing building blocks have been reported,which provide alternative protocols for synthesizing functional molecules.In this paper,we have efficiently realized the construction of n ew C-C bonds and C-P bonds,respectively,by transition metals mediate d the cleavage of inert sp³C-N bonds,and synthesized propargylamines and diarylmethyl phosphine oxides.The specific contents and research results are as follows:（1）Construction of sp C-sp³C bonds via palladium catalyzed cleavage of the inert sp³C-N bonds for synthesis of propargylamine compounds.By treatment of aminals with terminal alkynes in the presence of cat.Pd Br₂under ligand-and additive-free conditions,the corresponding propargylamines are readily produced in good yields.Compared with the reported methods,this reaction has wider scope of substrates and higher tolerance of functional groups.Phenylacetylene substituted by various functional groups（such as 4-alkyl,4-trifluoromethyl,4-halo,4-aldehyde）can produce the corresponding propargylamine compounds in moderate to excellent yields.Besides,heteroaryl substituted ferrocene acetylene,3-ethynylthiophene and aliphatic 1-octyne are also compatible with this system.Aminals derived from alkylamine,cyclic amine and benzylamine also are the good substrates.Therefore,this simple method will provide a simple way for the synthesis of propargylamine compounds.（2）Construction of sp³C-P（O）bonds via copper mediated cleavage of sp³C-N bonds for synthesis of diarylmethyl phosphine oxide s.By treatment of N-benzylic sulfonamides with P（O）H compounds in the presence of commercially available Cu Br₂,the corresponding diarylmethyl phosphine oxides are obtained in good yields.Compared with the reported methods,this approach avoids the use of halides,which is more environmentally friendly.The sulfonamides and P（O）H compounds bearing electron-withdrawing groups and electron-donating groups（such as met hyl,halogen,methoxy,etc.）are all compatible,giving the target product in moderate to good yields.Thus,this method will provide a simple and practical method for preparing diarylmethyl phosphine oxides.