Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)...Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)bond construction often rely on expensive and scarce transition metal catalysts,raising concerns about sustainability and environmental impact.To address these challenges,we develop a bifunctional photocatalyst,phloroglucinol carbon quantum dot(PG-CQD).It facilitates catalytic transfer hydrogenation(CTH)with IPA as the hydrogen donor.PG-CQDs exhibit both dehydrogenation and reduction activities,enabling the formation of vicinal diols under mild conditions with visible light irradiation.We propose a CTH mechanism that has been successfully validated through experiments.The catalytic system demonstrates remarkable versatility,enabling the synthesis of various vicinal diols from diverseα-keto ester substrates with good or excellent yields.These findings offer a sustainable synthetic strategy that aligns with green chemistry principles and establish a promising pathway for the development of environmentally benign and energy-efficient organic transformations.展开更多
The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydr...The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis.展开更多
The first efficiently N-heterocyclic carbene-catalyzed[4+2]cycloaddition of salicylaldehydes and pyrazole-4,5-diones to directly synthesis of spiro-ketal-pyrazolones bearing both oxygens of the ketal unit in the same ...The first efficiently N-heterocyclic carbene-catalyzed[4+2]cycloaddition of salicylaldehydes and pyrazole-4,5-diones to directly synthesis of spiro-ketal-pyrazolones bearing both oxygens of the ketal unit in the same ring was disclosed.This reaction was qualified with broad substrate scope,achieving moderate to excellent yield(up to 98%).This method has mild reaction conditions and simple operation,providing a new attractive strategy for the practical syntheses of multifunctionalized spiroketals including pyrazolone structures with mild reaction condition and operational simplicity.Furthermore,the gram scale and derivative transformations have also been achieved.展开更多
A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is ver...A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is very simple.A number of diazo esters and gem-difluoroalkenes are suitable for this reaction(36 examples),providing the desired products in good yields with excellent diastereoselectivity(>20∶1).展开更多
The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic comp...The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.展开更多
基金National Natural Science Foundation of China(Nos.21902023 and 21901252)Shanghai Pujiang Program,China(No.19PJ1400300)+1 种基金Professor of Special Appointment(Eastern Scholar),ChinaShanghai Institutions of Higher Education Fundamental Research Funds for the Central Universities,China(No.0900000155)。
文摘Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)bond construction often rely on expensive and scarce transition metal catalysts,raising concerns about sustainability and environmental impact.To address these challenges,we develop a bifunctional photocatalyst,phloroglucinol carbon quantum dot(PG-CQD).It facilitates catalytic transfer hydrogenation(CTH)with IPA as the hydrogen donor.PG-CQDs exhibit both dehydrogenation and reduction activities,enabling the formation of vicinal diols under mild conditions with visible light irradiation.We propose a CTH mechanism that has been successfully validated through experiments.The catalytic system demonstrates remarkable versatility,enabling the synthesis of various vicinal diols from diverseα-keto ester substrates with good or excellent yields.These findings offer a sustainable synthetic strategy that aligns with green chemistry principles and establish a promising pathway for the development of environmentally benign and energy-efficient organic transformations.
文摘The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis.
文摘The first efficiently N-heterocyclic carbene-catalyzed[4+2]cycloaddition of salicylaldehydes and pyrazole-4,5-diones to directly synthesis of spiro-ketal-pyrazolones bearing both oxygens of the ketal unit in the same ring was disclosed.This reaction was qualified with broad substrate scope,achieving moderate to excellent yield(up to 98%).This method has mild reaction conditions and simple operation,providing a new attractive strategy for the practical syntheses of multifunctionalized spiroketals including pyrazolone structures with mild reaction condition and operational simplicity.Furthermore,the gram scale and derivative transformations have also been achieved.
文摘A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is very simple.A number of diazo esters and gem-difluoroalkenes are suitable for this reaction(36 examples),providing the desired products in good yields with excellent diastereoselectivity(>20∶1).
文摘The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.
