Studies On The Homogeneous Gold Catalyzed Organic Reactions

This thesis is consisted of six chapters.The first chapter reviews the applications of gold catalysts in organic synthesis;the second one is focused on AuCl/AgOTf system-catalyzed stereoselective rearrangement of Baylis-Hillman acetates;the third one deals with HAuCl₄·4H₂O/O₂ system-catalyzed "one-pot" syntheis of 2-arylbenzoxazoles;the fourth chapter studies HAuCl₄·4H₂O/O₂ system-catalyzed oxidative aromatization of 1,3,5-trisubstituted pyrazolines;the fifth one investigates one-pot sequent cyclization-aromatization approach to the Synthesis of Hantzsch pyridine derivatives using HAuCl₄·4H₂O as Bifunctional Catalyst;the last one is conclusion and outlook of gold catalysis.In chapter one,firstly,we fully reviewed the physical and chemical properties of metal gold,the history of the development and current status of the application of gold catalysts in organic synthesis.On the basis of above background,the main ideas for designing of this thesis is discussed. In chapter two,AuCl/AgOTf system-catalyzed stereoselective rearrangement of Baylis-Hillman acetates was studied. 2-（acetoxymethyl）alk-2-enoates were prepared in good to high yields with 100%E-selectivity under very mild reaction conditions.In chapter three and four,HAuCl₄-4H₂O/O₂ system-catalyzed "one-pot" syntheis of 2-arylbenzoxazoles and oxidative aromatization of 1,3,5-trisubstituted pyrazolines to prepare 1,3,5-trisubstituted pyrazoles were investigated.Compared with conventional methods,the above two methods have advantages of lower catalyst loading,high chemoselectivity, mild reaction conditions,high yields and using O₂ as economical and environmentally benign oxidant.In chapter five,HAuCl₄·4H₂O promoted synthesis of Hantzsch 1,4-dihydropyridines and HAuCl₄·4H₂O/H₂O₂ system-catalyzed oxidative aromatization of Hantzsch 1,4-dihydropyridines was studied.An efficient one-pot synthesis of Hantzsch pyridine derivatives with high chemoselectivity and high yields is developed.In the last chapter,we draw some conclusions and made future outlook on the major opportunities of gold catalysts in organic synthesis.