The metal-free S–S bond exchange reaction of symmetrical disulfides catalyzed by NFSI is described. This novel protocol provides a facile and efficient approach to accessing important unsymmetrical disulfides.Further...The metal-free S–S bond exchange reaction of symmetrical disulfides catalyzed by NFSI is described. This novel protocol provides a facile and efficient approach to accessing important unsymmetrical disulfides.Furthermore, this strategy could also be utilized in the late-stage functionalization of amino acids, drugs,and natural products. The broad substrate scope, good functional group tolerance and easy accessibility of catalyst indicate that this strategy affords a green and practical complementary method to various unsymmetrical disulfides.展开更多
N-Fluorobenzenesulfonimide (NFSI) is one of the most popular fluorine-containing reagents for fluorination, imidation, sulfonylation, and oxidation reactions. Consequently, a variety of NFSI derivatives were designed ...N-Fluorobenzenesulfonimide (NFSI) is one of the most popular fluorine-containing reagents for fluorination, imidation, sulfonylation, and oxidation reactions. Consequently, a variety of NFSI derivatives were designed and synthesized to modify the reactivity and/or selectivity of the parent reagent. However, the hazardous F_(2) was inevitably required for the synthesis of NFSI derivatives. Herein, we disclosed a practical synthesis of various NFSI derivatives without F_(2) in common organic chemistry laboratories. This synthetic protocol started from NFSI through pyridine-promoted desulfonylation for formation of N-fluoroarenesulfonamide (ArSO_(2)NHF) and followed by condensation with arenesulfonyl chlorides. The reduction potentials and fluorinating reactivities of these NFSI derivatives demonstrated that NFSI derivatives bearing the electron-withdrawing groups on benzene ring had the higher oxidizing and fluorinating abilities than NFSI.展开更多
Cheap metal(Fe,Mn,and Co)-catalyzed hydroamination of alkenes has been an attractive method for synthesis of amines because of biocompatibility of metal,excellent Markovnikov selectivity and chemoselectivity.However,m...Cheap metal(Fe,Mn,and Co)-catalyzed hydroamination of alkenes has been an attractive method for synthesis of amines because of biocompatibility of metal,excellent Markovnikov selectivity and chemoselectivity.However,most reports are limited to unsaturated nitrogen sources(nitric oxide,azos,azides,cyano,etc.),for which aminated products are very limited.Notably,while used widely for fluorinating reaction,N-fluorobenzenesulfonimide(NFsI)as amine source for hydroamination has seldom been reported.Here we developed a cobalt-catalyzed intermolecular hydroamination of unactivated alkenes using NFSl as nitrogen source under mild conditions.The reaction exhibits excellent chemo-and regio-selectivity with no hydrofluorination or linear-selectivity products.Notably,the reaction proceeded with excellent yield even though the amount of Co(salen)catalyst was reduced to 0.2 mol%.Recently,a similar work was also reported by Zhang and coworkers(ref.19).展开更多
Herein,we reported a copper-catalyzed stereoselective olefinicβ-C(sp^(2))–H imidation of acyclic enamides employing commercially available N-fluorobenzenesulfonimide(NFSI)as an imidating reagent,which allows for the...Herein,we reported a copper-catalyzed stereoselective olefinicβ-C(sp^(2))–H imidation of acyclic enamides employing commercially available N-fluorobenzenesulfonimide(NFSI)as an imidating reagent,which allows for the synthesis of various imidation products with mainly E-selective control.This methodology was featured by being ligand-free,having good efficacy,and exhibiting broad substrate scope for acyclic enamides.Mechanistically,the imidyl radical species might be involved in the reaction.展开更多
Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to giv...Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.展开更多
基金the financial support from the National Natural Science Foundation of China (Nos. 21572026, 21702019)Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. SJCX20_0952)Advanced Catalysis and Green Manufacturing Collaborative Innovation Center, Changzhou University
文摘The metal-free S–S bond exchange reaction of symmetrical disulfides catalyzed by NFSI is described. This novel protocol provides a facile and efficient approach to accessing important unsymmetrical disulfides.Furthermore, this strategy could also be utilized in the late-stage functionalization of amino acids, drugs,and natural products. The broad substrate scope, good functional group tolerance and easy accessibility of catalyst indicate that this strategy affords a green and practical complementary method to various unsymmetrical disulfides.
基金The National Natural Science Foundation of China(21991211)the National Key Research and Development Program of China(2021YFF0701700)are greatly acknowledged for funding this work.
文摘N-Fluorobenzenesulfonimide (NFSI) is one of the most popular fluorine-containing reagents for fluorination, imidation, sulfonylation, and oxidation reactions. Consequently, a variety of NFSI derivatives were designed and synthesized to modify the reactivity and/or selectivity of the parent reagent. However, the hazardous F_(2) was inevitably required for the synthesis of NFSI derivatives. Herein, we disclosed a practical synthesis of various NFSI derivatives without F_(2) in common organic chemistry laboratories. This synthetic protocol started from NFSI through pyridine-promoted desulfonylation for formation of N-fluoroarenesulfonamide (ArSO_(2)NHF) and followed by condensation with arenesulfonyl chlorides. The reduction potentials and fluorinating reactivities of these NFSI derivatives demonstrated that NFSI derivatives bearing the electron-withdrawing groups on benzene ring had the higher oxidizing and fluorinating abilities than NFSI.
基金We declare no competing financial interests or personal relationships exiting in this article.And our work was supported by the National Natural Science Foundation of China(No.31972287).
文摘Cheap metal(Fe,Mn,and Co)-catalyzed hydroamination of alkenes has been an attractive method for synthesis of amines because of biocompatibility of metal,excellent Markovnikov selectivity and chemoselectivity.However,most reports are limited to unsaturated nitrogen sources(nitric oxide,azos,azides,cyano,etc.),for which aminated products are very limited.Notably,while used widely for fluorinating reaction,N-fluorobenzenesulfonimide(NFsI)as amine source for hydroamination has seldom been reported.Here we developed a cobalt-catalyzed intermolecular hydroamination of unactivated alkenes using NFSl as nitrogen source under mild conditions.The reaction exhibits excellent chemo-and regio-selectivity with no hydrofluorination or linear-selectivity products.Notably,the reaction proceeded with excellent yield even though the amount of Co(salen)catalyst was reduced to 0.2 mol%.Recently,a similar work was also reported by Zhang and coworkers(ref.19).
基金supported by the National Natural Science Foundation of China(22271062)Natural Science Foundation of Jiangxi Province(20242BAB26027).
文摘Herein,we reported a copper-catalyzed stereoselective olefinicβ-C(sp^(2))–H imidation of acyclic enamides employing commercially available N-fluorobenzenesulfonimide(NFSI)as an imidating reagent,which allows for the synthesis of various imidation products with mainly E-selective control.This methodology was featured by being ligand-free,having good efficacy,and exhibiting broad substrate scope for acyclic enamides.Mechanistically,the imidyl radical species might be involved in the reaction.
文摘Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.
