Study On Catalytic Asymmetric Oxidation Of Sulfides And Study On The Synthesis Of Arylchalcogenophosphates

There are two parts in this thesis.Part I:Chiral sulfoxides and their derivatives are extensively used as important chiral intermediates and auxiliaries, chiral ligands and catalysts, and chiral drugs such as esomeprazole. Chiral sulfoxides may be obtained by biological and chemical methods. Catalytic asymmetric oxidation of sulfides is the best method for synthesis of chiral sulfoxides with respect to atomic economy and practice. Although many advances have been achieved, many catalysts are limited in alkyl aryl sulfides. Besides, many kinds of substrates are to be developed. Thus, enantioselective sulfoxidation is an important project to be further studied.Based on previous research, firstly tandem enantioselective sulfoxidation and kinetic resolution catalyzed by simplest, cheapest Schiff base-vanadium complexes derived from many salicylaldehydes and chiral amino alcohols or amino acids, good yields and moderate to high enantioselectivities were obtained for the asymmetric oxidation of allyl(phenyl)sulfane (including its derivatives) at 0℃using H2O2 as oxidant. Moreover, the ee values can be improved up to 97.3% and the yield can retain 57% for allyl(phenyl)sulfane by slow dropwise-addition of H202 with the ligand prepared from (S)-t-leucinol and 3,5-diiodosalicylaldehyde. 72-92%ee and moderate to good yields were obtained for derivatives of allyl(phenyl)sulfane tested. Present studies show that the catalytic performance of VO(acac)2/Schiff base system can not be improved by addition of carboxylic acids or carboxylate salts。Natural D-camphor is abundant in China and extremely cheap. D- Camphane-1-amino-2-ol derived from it was firstly combined with V as catalyst and used in asymmetric oxidation of allyl(phenyl)sulfane, with 88%ee and 33%yield. The access pathway of sulfides is discussed based on the above catalytic results. Part II:Arylchalcogenophosphates are very useful synthetic intermediates for a variety of natural and complex molecules. For example, arylselenophosphates could be used in the palladium-catalyzed selenophosphorylation of terminal alkynes. Additionally, arylselenophosphates could offer phosphonyl radicals and react with alkenes generated by peroxides or azobisisobutyronitrile (AIBN). Thus how to efficiently synthesize arylchalcogenophosphates has been explored. Most of the methodologies available to synthesize arylchalcogenophosphates involved special reagents sensitive to air or moisture, complex handing and long reaction times, limiting thus their wide application. Furthermore, similar procedure using diaryl disulfides and diaryl ditellurides gave less satisfactory yields even for prolonged reaction time. Therefore, development of a general, efficient, economic method for the preparation of arylchalcogenophosphates is highly desirable.In our work, we have developed a new, fast and efficient procedure for the synthesis of arylchalcogenophosphates using copper iodide as a catalyst. The reaction proceeded smoothly without exclusion of moisture or air. Our procedure offers several relevant advantages including high atom economy by the use of both chalcogen atoms of the starting material, cheap catalyst, broad scope, mild conditions and high yields, which make this procedure a more desirable supplement to conventional chemical synthesis.