Study On Cyclization Cascades Of 1,7-diynes

Dialkynes have two reactive sites of C?C bonds,which makes their selectivity of diversification by synergistic effects during the reaction process.At present,most reactions involve metal-catalyzed self-cyclization of dialkynes,and metal-free radical-induced functionalization of dialkynes is relatively rare.In this dissertation,1,7-diynes were used as a key component,leading to the efficient synthesis of three types of different functionalized naphthalene derivatives under the radical or iodine-mediated conditions.There reactions maximize multiple functional groups of starting merails to interact with each other and make them into one molecular framework,thereby avoiding the separation and purification of the intermediates.These transformations reflect the high atomic utilization of the reaction and meet the requirements of green chemistry.The dissertation includes four parts as follows:The first part summarizes the research progress of the cascade cyclization reactions of dialkynes.On the basis of this literature survey,the novelity and innovation of this dissertation were described.In the second part,a new I₂-mediated intramolecular cyclization of 1,7-diynes was established.By using 1,7-diynes as the starting raw materials and molecular iodine as the catalyst,the reaction provided a range of unexpected 1-aroyl-2-naphthaldehydes with a 1,4-dicarbonyl unit.The resulting 1-aroyl-2-naphthaldehydes have been successfullyappliedinthesynthesisofbenzo[e]isoindol-3-onesand benzo[e]benzo[4,5]imidazo[2,1-a]isoindolesusingaromaticaminesand benzene-1,2-diamines as nucleophiles,respectively.Combining experimental results,several control reactions,and literature investigations,an appropriate reaction mechanism was proposed,which involved a 1,4-oxo-migration/[2+2]cycloaddition process to efficienty construct C-C and C-O bonds,thereby realizing cyclization cascade of 1,7-diynes.In the third part,a new sulfonyl radical-induced selenosulfonation of 1,7-diynes was developed.The copper-catalzyed reaction of 1,7-diynes with arylsulfonohydrazides and diphenyl diselenide was conducted.This new three component reaction proceeds smoothly under the mild conditions with a broad scope of substrates,providing 30examples of functionalized 3,4-dihydronaphthalenes in moderate to excellent yields.The resultant 3,4-dihydronaphthalenes may be applied to synthesize sulfur-and selenium-containing molecules.In the fourth part,a new cyclization of 1,7-diynes with double sulfur dioxide insertion was established.A novel metal-free double SO₂ insertion/multicomponent bicyclizationcascadesofbenzene-linked 1,7-diynes witharyldiazonium tetrafluoroborates and DABCO-bis?sulfur dioxide?were performed under redox-neutral conditions,providing 25 examples of dual sulfone-containing naphtho[1,2-c]thiophene2,2-dioxides with generally high stereoselectivity.The reaction pathway is proposed to proceed through the sequence of arylsulfonyl radical-induced 6-exo-dig/5-endo-trig bicyclization,H-abstraction and diazotization.In summary,this dissertation describes the efficient construction of a series of complex and diverse structures of carbocyclic and sulfone ring skeletons,delivering 87examples of new target products.The structures of these products were determined by nuclear magnetic resonance spectroscopy,infrared spectroscopy,high resolution mass spectrometry,etc,in which the structures of some compounds were confirmed by single crystal X-ray diffraction.The possible reaction mechanisms were also proposed by the corresponging controlled experiments.