Unnatural amino acids(UAAs)have broad applications in pharmaceutical sciences and biological studies.Current synthetic methods for UAAs mainly rely on asymmetric catalysis and often require several steps.There is a la...Unnatural amino acids(UAAs)have broad applications in pharmaceutical sciences and biological studies.Current synthetic methods for UAAs mainly rely on asymmetric catalysis and often require several steps.There is a lack of direct and simple methods.To address this challenge,we designed the LADA(labeling-activation-desulfurization-addition)strategy:selective labeling and activation of cysteine residues,the photocatalytic desulfurization and the subsequent radical addition to alkenes.Although composed of two steps,it is one-pot synthesis and has advantages such as high functional group tolerance,biocompatible reaction condition,and retained stereochemistry.This highly efficient strategy was successfully applied in the direct synthesis of unnatural amino acids and modifications of peptides with more than 50 examples.展开更多
A new electrochemical strategy for the atom transfer radical addition(ATRA)of polychloroalkanes across olefins has been realized by the synergism of paired electrolysis and halogen bonding activation.Notably,readily a...A new electrochemical strategy for the atom transfer radical addition(ATRA)of polychloroalkanes across olefins has been realized by the synergism of paired electrolysis and halogen bonding activation.Notably,readily accessible 4,4-di-tert-butyl bipyridine(dtbpy),acting as a halogen bonding acceptor,shifted the reduction potential of C—Cl bonds positively by 110 mV.The decreased operating potential leads to a wide substrate scope and excellent functional group compatibility.A diverse array of terminal and internal alkenes such as(hetero)aryl olefins,unactive aliphatic olefins,and natural products and drugs-derived olefins were well compatible.展开更多
Reversible deactivation radical polymerization(RDRP)provides unprecedented control over polymer composition,size,functionality,and topology.Various materials,such as linear polymers,star polymers,branched polymers,gra...Reversible deactivation radical polymerization(RDRP)provides unprecedented control over polymer composition,size,functionality,and topology.Various materials,such as linear polymers,star polymers,branched polymers,graft polymers,polymer networks,and hybrid materials,have been prepared by RDRP.The ability to control polymer topology also enabled precision synthesis of well-defined polymer topologies with degradable functional groups located at specific locations along a polymer chain.This review outlines progress in the synthesis of degradable polymers designed by RDRP,organized by topology and synthetic route.Recent progress in the depolymerization of polymers using RDRP mechanisms is highlighted and critically discussed.展开更多
A simple one-pot reaction that serves to functionalize graphite nanosheets(graphene)and single-walled carbon nanotubes(SWNTs)with perfluorinated alkyl groups is reported.Free radical addition of 1-iodo-1H,1H,2H,2H-per...A simple one-pot reaction that serves to functionalize graphite nanosheets(graphene)and single-walled carbon nanotubes(SWNTs)with perfluorinated alkyl groups is reported.Free radical addition of 1-iodo-1H,1H,2H,2H-perfluorododecane to ortho-dichlorobenzene suspensions of the carbon nanomaterial is initiated by thermal decomposition of benzoyl peroxide.Similarly,UV photolysis of 1-iodo-perfluorodecane serves to functionalize the carbon materials.Perfluorododecyl-SWNTs,perfluorododecyl-graphene,and perfluorodecyl-graphene are characterized by infrared(IR)and Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA),and atomic force microscopy(AFM).The products show enhanced dispersability in CHCl3 as compared to unfunctionalized starting materials.The advantage of this one-pot functionalization procedure lies in the use of pristine graphite as starting material thereby avoiding the use of harsh oxidizing conditions.展开更多
Unnatural amino acids(UAAs)are important building blocks in organic synthesis and drug discovery.They are also frequently integrated into peptides or proteins for biological studies.However,the direct and simplified s...Unnatural amino acids(UAAs)are important building blocks in organic synthesis and drug discovery.They are also frequently integrated into peptides or proteins for biological studies.However,the direct and simplified synthesis of UAAs remains a great challenge.At the same time,vast known peptide modifications are based on carbon-heteroatom bonds.There are no general methods for peptide modifications via the construction of C–C bonds.To address this challenge,herein we propose the LADA strategy,which is composed of two steps:the selective labeling and activation of cysteine residues,the desulfurization to generate carbon-centered radical and the radical addition to alkenes to build C–C bond.This one-pot protocol has obvious advantages such as good functional group tolerance,biocompatible reaction conditions,and retained stereochemistry.This strategy was successfully utilized for the synthesis of unnatural amino acids and direct modifications of peptides.展开更多
This review discusses the numerous routes to all-carbon quaternary centers based on the unique radical chemistry of xanthates. Itsummarizes the various approaches to the synthesis of tertiary xanthates then describes ...This review discusses the numerous routes to all-carbon quaternary centers based on the unique radical chemistry of xanthates. Itsummarizes the various approaches to the synthesis of tertiary xanthates then describes the intra- and intermolecular radicaladditions and combinations thereof that have so far been used to construct quaternary centers.展开更多
文摘Unnatural amino acids(UAAs)have broad applications in pharmaceutical sciences and biological studies.Current synthetic methods for UAAs mainly rely on asymmetric catalysis and often require several steps.There is a lack of direct and simple methods.To address this challenge,we designed the LADA(labeling-activation-desulfurization-addition)strategy:selective labeling and activation of cysteine residues,the photocatalytic desulfurization and the subsequent radical addition to alkenes.Although composed of two steps,it is one-pot synthesis and has advantages such as high functional group tolerance,biocompatible reaction condition,and retained stereochemistry.This highly efficient strategy was successfully applied in the direct synthesis of unnatural amino acids and modifications of peptides with more than 50 examples.
基金the National Natural Science Foundation of China(21871019,21901263,22171015)Beijing Municipal Education Committee Project(KZ202110005003,KM202110005006)Beijing Natural Science Foundation(2222003).
文摘A new electrochemical strategy for the atom transfer radical addition(ATRA)of polychloroalkanes across olefins has been realized by the synergism of paired electrolysis and halogen bonding activation.Notably,readily accessible 4,4-di-tert-butyl bipyridine(dtbpy),acting as a halogen bonding acceptor,shifted the reduction potential of C—Cl bonds positively by 110 mV.The decreased operating potential leads to a wide substrate scope and excellent functional group compatibility.A diverse array of terminal and internal alkenes such as(hetero)aryl olefins,unactive aliphatic olefins,and natural products and drugs-derived olefins were well compatible.
基金Financial support from NSF DMR 1921858 and NSF DMR 2202747 is acknowledgedsupport from the Harrison Fellowship(CMU Department of Chemistry).
文摘Reversible deactivation radical polymerization(RDRP)provides unprecedented control over polymer composition,size,functionality,and topology.Various materials,such as linear polymers,star polymers,branched polymers,graft polymers,polymer networks,and hybrid materials,have been prepared by RDRP.The ability to control polymer topology also enabled precision synthesis of well-defined polymer topologies with degradable functional groups located at specific locations along a polymer chain.This review outlines progress in the synthesis of degradable polymers designed by RDRP,organized by topology and synthetic route.Recent progress in the depolymerization of polymers using RDRP mechanisms is highlighted and critically discussed.
文摘A simple one-pot reaction that serves to functionalize graphite nanosheets(graphene)and single-walled carbon nanotubes(SWNTs)with perfluorinated alkyl groups is reported.Free radical addition of 1-iodo-1H,1H,2H,2H-perfluorododecane to ortho-dichlorobenzene suspensions of the carbon nanomaterial is initiated by thermal decomposition of benzoyl peroxide.Similarly,UV photolysis of 1-iodo-perfluorodecane serves to functionalize the carbon materials.Perfluorododecyl-SWNTs,perfluorododecyl-graphene,and perfluorodecyl-graphene are characterized by infrared(IR)and Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA),and atomic force microscopy(AFM).The products show enhanced dispersability in CHCl3 as compared to unfunctionalized starting materials.The advantage of this one-pot functionalization procedure lies in the use of pristine graphite as starting material thereby avoiding the use of harsh oxidizing conditions.
基金supported by the Shanghai Jiao Tong University(WF220417003 to Z.S.)。
文摘Unnatural amino acids(UAAs)are important building blocks in organic synthesis and drug discovery.They are also frequently integrated into peptides or proteins for biological studies.However,the direct and simplified synthesis of UAAs remains a great challenge.At the same time,vast known peptide modifications are based on carbon-heteroatom bonds.There are no general methods for peptide modifications via the construction of C–C bonds.To address this challenge,herein we propose the LADA strategy,which is composed of two steps:the selective labeling and activation of cysteine residues,the desulfurization to generate carbon-centered radical and the radical addition to alkenes to build C–C bond.This one-pot protocol has obvious advantages such as good functional group tolerance,biocompatible reaction conditions,and retained stereochemistry.This strategy was successfully utilized for the synthesis of unnatural amino acids and direct modifications of peptides.
基金Ecole PolytechniqueCNRS+7 种基金DGAMNRTThe Fondation Alfred Kastlerthe Royal Commission for the Exhibition of 1851the China Research CouncilAventis(now Sanofi)Rhodia(now Solvay)Syngenta
文摘This review discusses the numerous routes to all-carbon quaternary centers based on the unique radical chemistry of xanthates. Itsummarizes the various approaches to the synthesis of tertiary xanthates then describes the intra- and intermolecular radicaladditions and combinations thereof that have so far been used to construct quaternary centers.
