Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups in...Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups into the unsaturated bond in a single step,facilitating the efficient construction of complex molecular architectures,which has been widely utilized in material chemistry,pharmaceutical and fine chemical synthesis.Recently,significant progress has been made via free radical-mediated difunctionalization due to the extensive application of photocatalysis.However,highly selective difunc-tionalization reactions still remain challenging.The research progress of selective difunctionalization of unsaturated hydro-carbons using a free radical addition/functional group migration strategy over the past decade is summarized,and synthetic strategies and key reaction steps are systematically elaborated.展开更多
The study of new,unusual structures and reactivity patterns is of great interest for various field of organic and organometallic chemistry.Metallacycles of electropositive transition metals represent an excellent plat...The study of new,unusual structures and reactivity patterns is of great interest for various field of organic and organometallic chemistry.Metallacycles of electropositive transition metals represent an excellent platform for this purpose.In this work,we present the synthesis,characterisation,and reactivity toward carbodiimides of a set of ring-strained group 4 ansa-metallocene-based 1-metallacyclobuta-2,3-dienes Cp’_(2)M(Me_(3)SiC_(3)SiMe_(3))(M=Ti,Zr;Cp’_(2)=indenyl or tetrahydroindenyl based ansa-Cp ligand).In line with experimental studies,computational analysis of the electronic structure of new and previously reported 1-metallacyclobuta-2,3-dienes for the first time shows that the biradical character of these species not only depends on the metal,but also strongly on the nature of the cyclopentadienyl ligands.In reactions with carbodiimides RNvCvNR,depending on the substituents of the carbodiimide,either 2-aza-1-metallacyclobut-3-ene(R=iPr,Cy,and p-Tol)or 2-aza-1-metallacyclohexa-2,4,5-triene(R=SiMe_(3))complexes were produced.Mechanistic studies by DFT calculations reveal that 1,2-insertion of the carbodiimide followed by migration of a SiMe_(3) group of the metallacycle occurs for R=iPr,Cy,p-Tol,whereas for R=SiMe_(3) insertion is followed by SiMe_(3) migration along the carbodiimide.The reaction of a 2-aza-1-metallacyclobut-3-ene complex with benzophenone produces a zirconocene amidopyridine complex through a series of unprecedented bond activation and formation events,once again demonstrating the potential of early transition metal complexes for activation and transformation of small molecules.展开更多
Although functional group migration offers a unique strategy for molecular structural renovation,achieving selective migration within a given alkene while preserving the backbone,especially those demonstrating branche...Although functional group migration offers a unique strategy for molecular structural renovation,achieving selective migration within a given alkene while preserving the backbone,especially those demonstrating branched selectivity,remains a significant challenge.Here,we report the first catalytic,branch-selective cyanation of alkenes via a sulfinateassisted traceless functional group translocation strategy.This reaction operates through a sequential radical-polar crossover,group transfer,and elimination of a temporary radical source,enabling the efficient installation ofα,β-unsaturated nitriles with complete branched selectivity under mild photocatalytic conditions.Experimental and theoretical studies corroborate the proposed mechanism involving the addition and subsequent elimination of a temporary radical source.This method demonstrates broad substrate scope,accommodating aryl,alkyl,and heterocyclic compounds,as well as drug molecules and substituted internal olefins.展开更多
An unusual 1,3-addition products were obtained when amines were reacted withα,β-unsaturated aldehydes compounds in the presence of iodine and an oxidant.The versatile unsaturatedα-amino acetals are highly useful am...An unusual 1,3-addition products were obtained when amines were reacted withα,β-unsaturated aldehydes compounds in the presence of iodine and an oxidant.The versatile unsaturatedα-amino acetals are highly useful amino acid derivatives and can be converted to a wide variety of synthetically useful building blocks.Various control experiments have shown that the reaction proceeded via a mechanism involving the formation of imine/enamine intermediates followed by a 1,2-amine group migration reaction.展开更多
A conceptually novel,trifunctional sulfoximine-mediatedγ-functionalization of unactivated C(sp^(3))–H bonds has been achieved.The reaction is initiated by the photo-induced homolytic cleavage of an N–S bond in the ...A conceptually novel,trifunctional sulfoximine-mediatedγ-functionalization of unactivated C(sp^(3))–H bonds has been achieved.The reaction is initiated by the photo-induced homolytic cleavage of an N–S bond in the absence of photosensitizer,and proceeds sequentially through a cascade of 1,5-hydrogen atom transfer,1,4-functional group migration,desulfoximination and a Minisci reaction.A major feature of this approach is the use of sulfoximine as a traceless directing group.Other positive properties include mild conditions,simple operation,exclusive site-selectivity,high product diversity and the avoidance of additional photosensitizers.The protocol provides a new reaction mode for HAT-induced C(sp^(3))–H functionalization,and allows a much broader chemical space for sulfoximine studies.展开更多
A novel photoinduced intermolecular 1,2-arylheteroarylation of alkenes and the efficient synthesis of valuable polyarylalkanes are reported.The reaction is operationally simple,proceeds under mild conditions and with ...A novel photoinduced intermolecular 1,2-arylheteroarylation of alkenes and the efficient synthesis of valuable polyarylalkanes are reported.The reaction is operationally simple,proceeds under mild conditions and with no additional catalyst and reagents.The strategically designed radical cascade reaction is enabled by electron transfer,and involves cleavage of an inert C–C bond.The process features broad functional group compatibility as well as high product transformability.展开更多
文摘Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups into the unsaturated bond in a single step,facilitating the efficient construction of complex molecular architectures,which has been widely utilized in material chemistry,pharmaceutical and fine chemical synthesis.Recently,significant progress has been made via free radical-mediated difunctionalization due to the extensive application of photocatalysis.However,highly selective difunc-tionalization reactions still remain challenging.The research progress of selective difunctionalization of unsaturated hydro-carbons using a free radical addition/functional group migration strategy over the past decade is summarized,and synthetic strategies and key reaction steps are systematically elaborated.
基金Financial support by the Deutsche Forschungsgemeinschaft(Project No.452714985)is gratefully acknowledgedfinancial support by the China Scholarship Council(CSC,Grant No.202006380016).
文摘The study of new,unusual structures and reactivity patterns is of great interest for various field of organic and organometallic chemistry.Metallacycles of electropositive transition metals represent an excellent platform for this purpose.In this work,we present the synthesis,characterisation,and reactivity toward carbodiimides of a set of ring-strained group 4 ansa-metallocene-based 1-metallacyclobuta-2,3-dienes Cp’_(2)M(Me_(3)SiC_(3)SiMe_(3))(M=Ti,Zr;Cp’_(2)=indenyl or tetrahydroindenyl based ansa-Cp ligand).In line with experimental studies,computational analysis of the electronic structure of new and previously reported 1-metallacyclobuta-2,3-dienes for the first time shows that the biradical character of these species not only depends on the metal,but also strongly on the nature of the cyclopentadienyl ligands.In reactions with carbodiimides RNvCvNR,depending on the substituents of the carbodiimide,either 2-aza-1-metallacyclobut-3-ene(R=iPr,Cy,and p-Tol)or 2-aza-1-metallacyclohexa-2,4,5-triene(R=SiMe_(3))complexes were produced.Mechanistic studies by DFT calculations reveal that 1,2-insertion of the carbodiimide followed by migration of a SiMe_(3) group of the metallacycle occurs for R=iPr,Cy,p-Tol,whereas for R=SiMe_(3) insertion is followed by SiMe_(3) migration along the carbodiimide.The reaction of a 2-aza-1-metallacyclobut-3-ene complex with benzophenone produces a zirconocene amidopyridine complex through a series of unprecedented bond activation and formation events,once again demonstrating the potential of early transition metal complexes for activation and transformation of small molecules.
基金financial support from the National Natural Science Foundation of China(grant nos.22301093 and 22301228)National Key R&D Program(grant no.2023YFD1700500)self-determined research funds of Central China Normal University from the college’s basic research,and operation of Ministry of education of the people’s Republic of China and Wuhan Science and Technology Bureau.
文摘Although functional group migration offers a unique strategy for molecular structural renovation,achieving selective migration within a given alkene while preserving the backbone,especially those demonstrating branched selectivity,remains a significant challenge.Here,we report the first catalytic,branch-selective cyanation of alkenes via a sulfinateassisted traceless functional group translocation strategy.This reaction operates through a sequential radical-polar crossover,group transfer,and elimination of a temporary radical source,enabling the efficient installation ofα,β-unsaturated nitriles with complete branched selectivity under mild photocatalytic conditions.Experimental and theoretical studies corroborate the proposed mechanism involving the addition and subsequent elimination of a temporary radical source.This method demonstrates broad substrate scope,accommodating aryl,alkyl,and heterocyclic compounds,as well as drug molecules and substituted internal olefins.
基金support from the Distinguished University Professor grant(Nanyang Technological University)the Agency for Science,Technology,and Research(No.A^(*)STAR)under its MTC Individual Research grant(No.M21K2c0114)RIE2025 MTC Programmatic Fund(No.M22K9b0049)for T.P.L.
文摘An unusual 1,3-addition products were obtained when amines were reacted withα,β-unsaturated aldehydes compounds in the presence of iodine and an oxidant.The versatile unsaturatedα-amino acetals are highly useful amino acid derivatives and can be converted to a wide variety of synthetically useful building blocks.Various control experiments have shown that the reaction proceeded via a mechanism involving the formation of imine/enamine intermediates followed by a 1,2-amine group migration reaction.
基金supported by the National Natural Science Foundation of China(21971173,22001185,22171201)the Natural Science Foundation of Jiangsu Province(BK20200852)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘A conceptually novel,trifunctional sulfoximine-mediatedγ-functionalization of unactivated C(sp^(3))–H bonds has been achieved.The reaction is initiated by the photo-induced homolytic cleavage of an N–S bond in the absence of photosensitizer,and proceeds sequentially through a cascade of 1,5-hydrogen atom transfer,1,4-functional group migration,desulfoximination and a Minisci reaction.A major feature of this approach is the use of sulfoximine as a traceless directing group.Other positive properties include mild conditions,simple operation,exclusive site-selectivity,high product diversity and the avoidance of additional photosensitizers.The protocol provides a new reaction mode for HAT-induced C(sp^(3))–H functionalization,and allows a much broader chemical space for sulfoximine studies.
基金the National Natural Science Foundation of China(21971173)the Project of Scientific and Technologic Infrastructure of Suzhou(SZS201905)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘A novel photoinduced intermolecular 1,2-arylheteroarylation of alkenes and the efficient synthesis of valuable polyarylalkanes are reported.The reaction is operationally simple,proceeds under mild conditions and with no additional catalyst and reagents.The strategically designed radical cascade reaction is enabled by electron transfer,and involves cleavage of an inert C–C bond.The process features broad functional group compatibility as well as high product transformability.
