Study On The Reactions Involving Amines,Ethers And Dicarbonyl Compounds Based On Iodonium Ylides-Lewis Bases Halogen Bonding Complex

Since the first stable iodonium ylide was synthesized by Neiland sixty years ago,iodonium ylides were mainly used as precursors to produce carbene or carbenoid species.In addition,few reports also revealed that iodonium ylides could be used as electrophiles or nucleophiles.Although significant advances have been made in the development of new reactions with iodonium ylides,the exploration of new reaction modes of iodonium ylides-mediated approaches is highly desirable.In this thesis,we systematically developed a series of new reactions based on the new reaction mode of iodonium ylides-Lewis bases halogen-bonding complexes.These new reactions include the direct cyclization of tertiary aryl amines and unprotected aliphatic amines,the transformation of ethers and the cyclization of dicarbonyl compounds.The thesis mainly consists of four parts:Part 1.Cyclization of tertiary aryl amines with iodonium ylidesThis thesis developed the direct cyclization of tertiary aryl amines with iodonium ylides based on the reaction mode of iodonium ylides-tertiary aryl amines halogen-bonding complex.The complex of iodonium ylides and tertiary aryl amines can induce an electron-transfer process to generate a radical ion pair.Furthermore,iodonium ylides can abstract two hydrogen atoms of tertiary aryl amines,thus enabling the direct cyclization of unmodified tertiary aryl amines without assistance of a transition-metal catalyst and/or additional initiator/oxidant.This cyclization reaction is operationally simple as it only requires mixing the two reactants together to give a broad range of indoline derivatives within several minutes.This study uncovers an exceptional property of iodonium ylides and potentially opens new avenues for exploring chemical transformations involving amines,ethers and the other Lewis bases.Part 2.Cyclization of aliphatic amines with iodonium ylidesBased on the reaction mode of iodonium ylides-Lewis bases halogen-bonding complex,we have further established the direct cyclization of aliphatic amines with iodonium ylides.The unprotected aliphatic amines usually coordinate with transition metal catalysts,thus deactivating the transition metal catalysts.Moreover,these unprotected aliphatic amines are not compatible with oxidants as they readily undergo deterioration under oxidative conditions.Thus,the transformation of unprotected aliphatic amines through the cleavage of C-H bonds remains one of challenging topics in organic synthesis.In particular,the transformation of unprotected aliphatic amines via ?-C-H functionalization approaches is a significantly unresolved problem.The research in this thesis found that iodonium ylides could activate aliphatic amines to deliver a diverse array of N-heterocyclic products.This transformation could tolerate a broad range of unprotected aliphatic amines including both linear and cyclic amines,generating diverse N-heterocycles with reasonable yields.Part 3.Transformation of ethers by iodonium ylidesBased on iodonium ylides-ethers halogen-bonding complex,the research in this thesis found that iodonium ylides could activate ethers,thus inducing the cleavage of C-O bond in ether followed by the reconstruction of a new C-O bond with iodonium ylides.This study found that the addition of borate or boron trifluoride could significantly enhance the interaction strength of the iodonium ylides-ethers halogen-bonding complex,which induces a single electron transfer process and finally leads to the cleavage and reconstruction of C-O bond.The reaction approach developed in this thesis is suitable for both cyclic and linear ethers.Under mild conditions,these reactions involving the cleavage and reconstruction of C-O bonds proceeded smoothly.The results described in this study provide significant insights for the exploration of new transformations of the other oxygen-containing Lewis bases with iodonium ylides.Part 4.Cyclization of dicarbonyl compounds with iodonium ylidesDihydrofuran derivatives represent an important class of oxygen-containing heterocyclic compounds which present as the core skeletons of many natural products and drug molecules.Based on the reaction mode of iodonium ylides-Lewis bases halogen-bonding complex,the research in this thesis found that iodonium ylides could activate the in situ generated enol from dicarbonyl compounds,thus leading to a cyclization reaction of dicarbonyl compounds with iodonium ylides.This cyclization reaction could tolerate a broad range of aliphatic and aryl dicarbonyl compounds to give a broad range of dihydrofuran derivatives with reasonable yields.This reaction approach is also applicable to the construction of other heterocyclic compounds such as dihydropyrans.The synthetic method established in this thesis provides a new approach to the construction of the oxygen-containing heterocyclic skeletons.