Amphiphilic Zwitterionic Phosphine:Synthesis,Characterization And Applications To Au(Ⅰ) Catalyzed Hydration And A~3-coupling

The hydration of terminal alkynes and A³-coupling（three-component coupling reaction of aldehydes,amines,and terminal alkynes）are useful protocol to produce ketone and propargylamines with advantages of 100%atom economy.It has been well known that the carbonyl compounds and propargylamines are important intermediates in organic synthesis.Due to the unique eletrophilicity to alkynes,Au-complexes can exhibit good catalytic performance in the hydration of alkynes and A³-coupling.It is believed that the electronic and steric effects of the phosphine could dramatically influence the catalytic performance of Au-complexes for the hydration of terminal alkynes and A³-coupling.In addition,it is necessary to add auxiliary additives to the catalytic system,such as the silver salts and/or strong acids,while the catalyst is unstable and difficult to recycle for the hydration of terminal alkynes and A³-coupling.In this thesis,based on the existing problems in the hydration of terminal alkynes and A³-coupling,firstly we developed a hybrid P,O-ligand containing one hard（O-）donor（-SO₃^-）,one soft（P-）donor（phosphino-fragment）and positive-charged phosphonium[P（V）⁺].The catalytic performance of L1-based Au-catalyst was investigated free of any auxiliary additives for hydration of terminal alkynes.The investigation of catalytic performance indicated that:（1）the strong electron-withdrawing effect coming from the Lewis acidic phosphonium[P（V）⁺]might be an inherent driving force to rupture Au⁺-Cl^-bond,then the active P-Au⁺species could be formed without the requirement of the addition of auxiliary acids or silver salts;（2）the active P-Au⁺species was protected timely by available-SO₃^-group from the L1 ligand against deactivation;（3）the amphiphilic nature of L1 rendered both H₂O molecules and alkynes better accessibility to P-Au⁺catalytic sites,which also gave rise to the reaction rate.What’s more,as an ionic ligand,L1-based Au-catalyst could be recycled for 5 runs in RTIL medium（[Bmim]PF₆）.In addition,the catalytic performance of L1-based Au-catalyst was investigated free of any auxiliary additives for A³-coupling.It was found that the strong electron-withdrawing effect coming from the Lewis acidic phosphonium[P（V）⁺]and the weak coordination coming from-SO₃^-group promoted the formation of P-Au⁺species,as well as the condensation of aldehydes with amines.Therefore,L1-based Au-catalyst exhibited excellent activity towards A³-coupling without solvent and auxiliary additives.In addition,the catalytic system exhibited good generality for the A³-coupling of the different alkynes（aromatics and aliphatic alkynes）,formaldehyde and secondary amines.