Studies On The Palladium-catalyzed Cascade Cycloaddition And Rearrangement Reactions Of Sulfoximines With Ynamides

The sulfoximine moiety widely exists in drug molecules,agrochemicals,and bioactive natural products.Sulfoximines can be used as organocatalyst,chiral ligand or directing groups,and as key intermediate in the construction of heterocyclic compounds.On the other hand,ynamide is a kind of compound with multiple uses,in which the nitrogen atom is directly connected with the carbon-carbon triple bond of alkynes.The ynamide derivatives can be used as efficative synthetic building blocks,particularly in the rapid construction of aza-heterocyclic compounds.This paper mainly focused on the transition-metal-catalyzed tandem cycloaddition and rearrangement reactions of sulfoximines with ynamides,to construct divergent aminated sulfoximine derivatives.The main contents are presented as below.In the first part,transition-metal-catalyzed synthetic transformations of sulfoximines with unsaturated hydrocarbons are reviewed.The mechanisms of some of the reactions were briefly described.In the second part,the palladium-catalyzed tandem cascade cycloaddition reaction of aryl sulfoximines with ortho-bromoaryl ynamides was developed.The acetyl(Ac)group was found to be an optimal protecting group in NH-sulfoximine to reduce the nucleophilic ability of nitrogen atom,and Me OH was a good de-protecting agent in this reaction,thus efficiently suppressing the formation of intramolecular cyclization byproduct.A series of aminated tetracyclic 1,2-benzothiazepine 1-oxide compounds are obtained in excellent yields.The structure of the targeted molecule was confirmed by single-crystal X-ray diffraction analysis.Mechanistically,a palladium-catalyzed double C-Pd cis-insertion into alkynes/cyclization sequences was proposed.Under the optimized mild reactionconditions,the fused-tetracyclic heterocyclic products were obtained by this one-step reaction with excellent chemoand regioselectivity.In the third part,a palladium-catalyzed addition/3,3-sigma rearrangement reaction of sulfoximines with N-allylic ynamides was developed.This reaction undergo a 3,3-sigma rearrangement reactionwas to synthesize an A series of amide imino sulfoximines with potential pharmaceutical activities were efficiently prepared from this one-pot multi-step transformation.The structure of the targeted molecule was confirmed by single-crystal X-ray diffraction analysis.