Synthesis Of 1,2,3-oxathiazolidine-2-oxides Through Palladium-catalyzed [3+2] Cycloaddition Reaction

Organosulfur compounds play important roles in biomedicine,organic synthesis and industrial applications because of their unique physical and chemical properties.As a result,the construction of organosulfur compounds with different structures and functions represents an active research area in organic synthesis.In this dissertation,the preparation of 1,2,3-oxathiazolidine-2-oxides is studied.As an important building block,1,2,3-oxathiazolidine-2-oxides allow for divergent post-modifications to access downstream derivatives of diverse chemical structures.There are three chapters in this dissertation.In the first chapter,the research progress of 1,2,3-oxathiazolidine-2-oxides and N-sulfinylamines are summarized.Oxathiazolidines are a special class of cyclic compounds containing three consecutive heteroatoms that can be used as building blocks for the preparation of 1,2,3-oxathiazolidine-S,S-dioxides and sulfinyl compounds.In addition,oxathiazolidines also have important applications in the synthesis of achiral or chiral β-amines,N,P-ligands and bioactive molecules.On the other hand,N-sulfinylamines are heterocumulenes that are often used for the construction of cyclic sulfur(IV)-containing compounds.In the second chapter,a novel method for the 1,2,3-oxathiazolidine-2-oxides synthesis is developed.The 1,2,3-oxathiazolidine-2-oxides of diverse structures are prepared via palladium-catalyzed [3+2] cycloaddition reaction between vinylethylene carbonates and N-sulfinylamines.It should be pointed out that the highly reactive allylpalladium intermediate is the key to the success of the reaction.The obtained products can be transformed into 1,2,3-oxathiazolidine-S,S-dioxides,amino alcohols,sulfoxides,β-amines,etc.through concise derivatization.The gram-scale experiments performed well and also confirmed its practicality in organic synthesis.In the third chapter,the 1,2,3-oxathiazolidine-2-oxides are prepared through an alternative protocol.The [3+2] cycloaddition reaction between vinyl epoxides and N-sulfinylamines via the highly reactive allylpalladium intermediate has been realized.The method is simple and efficient without base additives,as well as specific regioselectivity.The advantages of the two methods are complementary,providing a convenient and practical method for the construction of oxathiazolidines.