Radical/radical cross-coupling represents a straightforward way for the construction of new chemical bonds in theory and has received more and more attention over the past several years. Until now, it is challenging t...Radical/radical cross-coupling represents a straightforward way for the construction of new chemical bonds in theory and has received more and more attention over the past several years. Until now, it is challenging to achieve the selective bond formation between two transient radicals since selective radical cross-coupling usually happens between persistent radical and transient radical. However, the number of persistent radicals is much less than that of transient radicals. These issues limit the application of radical/radical cross-coupling in the construction of new chemical bonds. To solve this, we proposed a novel strategy ‘‘tuning radical reactivity" that could tune transient radical into persistent radical. This paper will introduce the concept and recent developments of ‘‘tuning radical reactivity".展开更多
The electrochemical utilization of electron-deficient methylarenes for radical-radical cross-couplings remains very rare.Enabled by an umpolung strategy,the unprecedented electrochemical cross-coupling of electron-def...The electrochemical utilization of electron-deficient methylarenes for radical-radical cross-couplings remains very rare.Enabled by an umpolung strategy,the unprecedented electrochemical cross-coupling of electron-deficient methylarenes with aldehydes was developed.The paired electrolysis simultaneously generated electron-deficient benzylic radicals and ketyl radicals at both electrodes,which then underwent radical recombination,governed by polarity matching and persistent-radical effect(PRE)to afford functionalized alcohols that are not easily accessible by other methods.This protocol features catalystand external redox agent-free conditions and a formal 100%atom economy.Mechanistic studies support the radical-radical cross-coupling pathway.展开更多
A novel photoredox-neutral ring-opening pyridylation of non-prefunctionalized cyclic oximes has been accomplished through phosphoranyl radical-mediated N-O/C-C bond cleavages followed by radicalradical coupling.This m...A novel photoredox-neutral ring-opening pyridylation of non-prefunctionalized cyclic oximes has been accomplished through phosphoranyl radical-mediated N-O/C-C bond cleavages followed by radicalradical coupling.This mild acid-,base-,and oxidant-free protocol provides highly site-selective and efficient access to distally pyridylated alkylnitriles,which could be scale-up synthesized and readily converted into skeletally diverse compounds.Notably,the oxidized ground-state photocatalyst generated via the SET oxidation of the highly reducing excited-state photocatalyst by cyanopyridines might initiate the following phosphoranyl radical-mediated deoxygenative process.展开更多
Umpolung reactions of C=X bonds(X=O,N)are valuable ways of constructing new C–C bonds,which are sometimes difficult to be constructed using traditional synthetic pathways.Classical polarity inversion of C=X bonds(X=O...Umpolung reactions of C=X bonds(X=O,N)are valuable ways of constructing new C–C bonds,which are sometimes difficult to be constructed using traditional synthetic pathways.Classical polarity inversion of C=X bonds(X=O,N)usually requires air or moisture‐sensitive and strong reducing agents,which limit the feasibility of substrate scope.Herein we describe a photo‐induced reductive cross‐coupling reaction of aldehydes,ketones and imines with electron‐deficient arenes(aromatic nitriles)using fac‐Ir(ppy)3as a photocatalyst and diisopropylethylamine(DIPEA)as a terminal reductant under visible light irradiation.Mild conditions and high yields mean that this new polarity inversion strategy can be used with aryl‐substituted alcohols and amines.Spectroscopic studies and control experiments have demonstrated the oxidative quenching of Ir(ppy)3*by electron‐deficient arenes involved in the key step for the C–C bond formation.展开更多
Organic radical as a powerful tool has been extensively applied in synthetic chemistry. However, harnessing radical-mediated noncovalent interactions to fabricate soft materials remains elusive. Here we report a new c...Organic radical as a powerful tool has been extensively applied in synthetic chemistry. However, harnessing radical-mediated noncovalent interactions to fabricate soft materials remains elusive. Here we report a new category of supramolecular hydrogel system held by multiple radical-radical(polyradical) interactions, and its photosensitive cross-linking structure. A simple polyacrylamide with triarylamine(TAA)pendants is designed as the precursor. The TAA units in polymer can be converted into active TAA^(·+)radical cations with light and further associate each other via TAA^(·+)–TAA^(·+)stacking interactions to form stable supramolecular network. Temporal control of the light irradiation dictates the degree of radical stacks, thus regulating the mechanical performance of the resulting hydrogel materials on-demand. Moreover, the reversible collapse of this hydrogels can be promoted by adding radical scavenger or exerting reduction voltage.展开更多
UV/H2O2 and UV/peroxodisulfate （PDS） processes were adopted to degrade a typical β-blocker atenolol （ATL）. The degradation efficiencies under various operational parameters （oxidant dosage, pH, HCO3-, humic acid...UV/H2O2 and UV/peroxodisulfate （PDS） processes were adopted to degrade a typical β-blocker atenolol （ATL）. The degradation efficiencies under various operational parameters （oxidant dosage, pH, HCO3-, humic acid （HA）, NO3- , and Cl-） were compared. Principal factor analysis was also performed with a statistical method for the two processes. It was found that increasing the specific dosage of the two peroxides （[peroxide]0/[ATL]0 ） ranging from 1：1 to 8：1 led to a faster degradation rate but also higher peroxide residual. Within the pH range 3-11, the optimum pH was 7 for the UV/PDS process and elevating pH benefitted the UV/H 2O2 process. The presence of HCO3- , HA, and Cl adversely affected ATL oxidation in both processes. The NO3- concentration 1-3 mmol/L accelerated the destruction of ATL by the UV/PDS process, but further increase of NO3- concentration retarded the degradation process, contrary to the case in the UV/H2O2 process. The rank orders of effects caused by the six operational parameters were pH ≈ specific dosage 〉 [HA]0 〉 [NO3-]0 〉 [HCO3-]0 〉 [Cl-]0 for the UV/H2O2 process and specific dosage 〉 pH 〉 [HA]0 〉 [NO3-]0 〉 [HCO3-]0 〉[Cl-]0 for the UV/PDS process. The UV/PDS process was more sensitive to changes in operational parameters than the UV/H2O2 process but more efficient in ATL removal under the same conditions.展开更多
基金supported by the National Natural Science Foundation of China(21390402,21520102003)the Hubei Provincial Natural Science Foundation(2017CFA010)The Program of Introducing Talents of Discipline to Universities of China(111 Program)
文摘Radical/radical cross-coupling represents a straightforward way for the construction of new chemical bonds in theory and has received more and more attention over the past several years. Until now, it is challenging to achieve the selective bond formation between two transient radicals since selective radical cross-coupling usually happens between persistent radical and transient radical. However, the number of persistent radicals is much less than that of transient radicals. These issues limit the application of radical/radical cross-coupling in the construction of new chemical bonds. To solve this, we proposed a novel strategy ‘‘tuning radical reactivity" that could tune transient radical into persistent radical. This paper will introduce the concept and recent developments of ‘‘tuning radical reactivity".
基金the National Natural Science Foundation of China(grant nos.22271009 and 22171015)Beijing Natural Science Foundation(grant no.2222003)Beijing Municipal Education Committee Project(grant nos.KZ202110005003 and KM202110005006).
文摘The electrochemical utilization of electron-deficient methylarenes for radical-radical cross-couplings remains very rare.Enabled by an umpolung strategy,the unprecedented electrochemical cross-coupling of electron-deficient methylarenes with aldehydes was developed.The paired electrolysis simultaneously generated electron-deficient benzylic radicals and ketyl radicals at both electrodes,which then underwent radical recombination,governed by polarity matching and persistent-radical effect(PRE)to afford functionalized alcohols that are not easily accessible by other methods.This protocol features catalystand external redox agent-free conditions and a formal 100%atom economy.Mechanistic studies support the radical-radical cross-coupling pathway.
基金supported by the National Natural Science Foundation of China(Nos.22101237,22171233,22001220)the Open Project Program of Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province(No.HYX21003)+1 种基金the Open Project Program of State Key Laboratory of Natural and Biomimetic Drugs(No.K202105)the Scientific Fund of Sichuan Province(Nos.2022NSFSC1219,21YYJC0697)。
文摘A novel photoredox-neutral ring-opening pyridylation of non-prefunctionalized cyclic oximes has been accomplished through phosphoranyl radical-mediated N-O/C-C bond cleavages followed by radicalradical coupling.This mild acid-,base-,and oxidant-free protocol provides highly site-selective and efficient access to distally pyridylated alkylnitriles,which could be scale-up synthesized and readily converted into skeletally diverse compounds.Notably,the oxidized ground-state photocatalyst generated via the SET oxidation of the highly reducing excited-state photocatalyst by cyanopyridines might initiate the following phosphoranyl radical-mediated deoxygenative process.
文摘Umpolung reactions of C=X bonds(X=O,N)are valuable ways of constructing new C–C bonds,which are sometimes difficult to be constructed using traditional synthetic pathways.Classical polarity inversion of C=X bonds(X=O,N)usually requires air or moisture‐sensitive and strong reducing agents,which limit the feasibility of substrate scope.Herein we describe a photo‐induced reductive cross‐coupling reaction of aldehydes,ketones and imines with electron‐deficient arenes(aromatic nitriles)using fac‐Ir(ppy)3as a photocatalyst and diisopropylethylamine(DIPEA)as a terminal reductant under visible light irradiation.Mild conditions and high yields mean that this new polarity inversion strategy can be used with aryl‐substituted alcohols and amines.Spectroscopic studies and control experiments have demonstrated the oxidative quenching of Ir(ppy)3*by electron‐deficient arenes involved in the key step for the C–C bond formation.
基金fund support of the National Natural Science Foundation of China (Nos. 21674022 and 51703034)the National Defense Science and Technology Innovation Zone (No. 163 Program)the Shanghai Rising-Star Program (No. 19QA1400700)。
文摘Organic radical as a powerful tool has been extensively applied in synthetic chemistry. However, harnessing radical-mediated noncovalent interactions to fabricate soft materials remains elusive. Here we report a new category of supramolecular hydrogel system held by multiple radical-radical(polyradical) interactions, and its photosensitive cross-linking structure. A simple polyacrylamide with triarylamine(TAA)pendants is designed as the precursor. The TAA units in polymer can be converted into active TAA^(·+)radical cations with light and further associate each other via TAA^(·+)–TAA^(·+)stacking interactions to form stable supramolecular network. Temporal control of the light irradiation dictates the degree of radical stacks, thus regulating the mechanical performance of the resulting hydrogel materials on-demand. Moreover, the reversible collapse of this hydrogels can be promoted by adding radical scavenger or exerting reduction voltage.
文摘UV/H2O2 and UV/peroxodisulfate （PDS） processes were adopted to degrade a typical β-blocker atenolol （ATL）. The degradation efficiencies under various operational parameters （oxidant dosage, pH, HCO3-, humic acid （HA）, NO3- , and Cl-） were compared. Principal factor analysis was also performed with a statistical method for the two processes. It was found that increasing the specific dosage of the two peroxides （[peroxide]0/[ATL]0 ） ranging from 1：1 to 8：1 led to a faster degradation rate but also higher peroxide residual. Within the pH range 3-11, the optimum pH was 7 for the UV/PDS process and elevating pH benefitted the UV/H 2O2 process. The presence of HCO3- , HA, and Cl adversely affected ATL oxidation in both processes. The NO3- concentration 1-3 mmol/L accelerated the destruction of ATL by the UV/PDS process, but further increase of NO3- concentration retarded the degradation process, contrary to the case in the UV/H2O2 process. The rank orders of effects caused by the six operational parameters were pH ≈ specific dosage 〉 [HA]0 〉 [NO3-]0 〉 [HCO3-]0 〉 [Cl-]0 for the UV/H2O2 process and specific dosage 〉 pH 〉 [HA]0 〉 [NO3-]0 〉 [HCO3-]0 〉[Cl-]0 for the UV/PDS process. The UV/PDS process was more sensitive to changes in operational parameters than the UV/H2O2 process but more efficient in ATL removal under the same conditions.
