Study On The Michael Addition/Cyclization Tandem Reaction Of Cyclic Sulfonimide Unsaturated Compounds

There are many natural chiral compounds in nature.Now more than half of the drugs we commonly use are chiral compounds.There are also many chiral compounds in our bodies,such as proteins,ribonucleic acids?DNA?,sugars,etc.The study of new methods for the synthesis of chiral compounds is very important.Among them,asymmetric catalytic reactions have become widely used in modern organic synthesis due to their high reactivity,good selectivity,low pollution,high economic value,and environmental protection.method.The first part of this thesis:we use cheap quinine as an organic molecular catalyst,and?E?-3-styrylbenzo[d]isothiazole 1,1-dioxide and malononitrile in dichloromethane?DCM?solvent at 25^oC.Asymmetric catalysis of Michael addition cyclization tandem reaction of dioxide and malononitrile for hydrogen transfer,a series of chirality with high enantioselectivity?up to 99%ee?was synthesized in a yield of about 95%7-amino-9-phenyl-9H-benzo[4,5]isothiazolo[2,3-a]pyridine-8-carbonitrile 5,5-dioxide d-erivative,the structure of the resulting product was determined ¹H-NMR,¹³C-NMR,HRMS and other characteristics were identified,and the enantioselectivity of the product was confirmed by HPLC.The method has the advantages of cheap catalyst,mild reaction conditions and simple operation.In the second part of this thesis,we use tetratriphenylphosphine palladium as the catalyst,and?E?-3-styrylbenzo[d]isothiazole 1,1-dioxide and 2-methyl-2-vinyloxirane in toluene solvent at 25^oC.A series of?E?-3-methyl-9b-styryl-3-vinyl-2,3-dihydro-9bH-benzo[4,5]isothiazolo[3,2-b]oxazole-5,5-dioxide derivatives,and the structure was characterized by ¹H-NMR and ¹³C-NMR.