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
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
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.
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.
