A photoinduced intramolecular charge transfer complex(ICTC)-enabled photoreduction of trifluoromethyl phosphonium salt for the trifluoromethylation of heteroarenes was developed.It offers a convenient approach to intr...A photoinduced intramolecular charge transfer complex(ICTC)-enabled photoreduction of trifluoromethyl phosphonium salt for the trifluoromethylation of heteroarenes was developed.It offers a convenient approach to introduce trifluoromethyl group to a wide range of aromatic heterocycles,such as indoles,pyrrole,substituted benzene,coumarin,and chromone.This strategy provides operational simplicity,photocatalyst-,transition metal-,and oxidant-free conditions,making it highly advantageous.展开更多
The transition metal-free chalcogen trifluoromethylation of alkenes represents a highly efficient transformation for the rapid generation of C(sp3)-rich aliphatic trifluoromethyl compounds. However, a unified methodol...The transition metal-free chalcogen trifluoromethylation of alkenes represents a highly efficient transformation for the rapid generation of C(sp3)-rich aliphatic trifluoromethyl compounds. However, a unified methodology to achieve oxy-, thio-, and seleno-trifluoromethylation remains elusive yet highly desirable. In this study, we report a triarylamine-catalyzed three-component vicinal chalcogen-trifluoromethylation of alkenes under blue light irradiation without the need of transition metal catalyst. This reaction is broadly applicable to oxy, thio, and seleno nucleophiles, facilitating modular access to a diverse array of β-trifluoromethyl alcohols, ethers, thioethers, thiocyanates, and selenocyanates with good yields and predictable regioselectivities (61 examples). Additionally, we demonstrate its application in the late-stage modification of natural products and pharmaceutical compounds. Preliminary mechanistic studies suggest that a catalytic electron donor-acceptor (EDA) complex between triarylamine and the Umemoto reagent is key to enabling the radical/polar crossover process.展开更多
A new electrochemical strategy for trifluoromethylation/cyclization using TfNHNHBoc as a CF_(3)source was established.This approach was realized by the direct electrolysis of Tf NHNHBoc under external oxidantfree and ...A new electrochemical strategy for trifluoromethylation/cyclization using TfNHNHBoc as a CF_(3)source was established.This approach was realized by the direct electrolysis of Tf NHNHBoc under external oxidantfree and catalyst-free conditions,and afforded various trifluoromethylated oxindoles with good functional group compatibility and broad substrate scope.Preliminary mechanistic studies show that the reaction proceeds by a radical process.展开更多
Difluorocarbene has emerged as a valuable intermediate to synthesize fluorides.However,difluorocarbene-derived synthesis of^(19)F/^(18)F-trifluoromethyl triazoles has not been explored.Herein,we reported the Cu(I)-pro...Difluorocarbene has emerged as a valuable intermediate to synthesize fluorides.However,difluorocarbene-derived synthesis of^(19)F/^(18)F-trifluoromethyl triazoles has not been explored.Herein,we reported the Cu(I)-promoted difluorocarbene-derived^(19)F/^(18)F-trifluoromethylation of iodotriazoles using KF/K^(18)F as the fluorine source.This approach rapidly generated a wide range of 5-trifluoromethyl-1,2,3-triazoles in good yields showing high functional group compatibility.The reaction was effective for late-stage functionalization of bioactive molecules and^(18)F-trifluoromethylation of iodotriazoles.This work provides a practical synthetic methodology for the development of triazole drugs and^(18)F-radiotracers for positron emission tomography.展开更多
In the presence of copper （I） halide as catalyst, a variety of carbonyl compounds could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields.
A copper-catalyzedα-selective C–H trifluoromethylation of acrylamides with TMSCF3 is described.A wide range of arenes and heteroarenes at theβ-position of acrylamides are compatible with the reaction,affording the ...A copper-catalyzedα-selective C–H trifluoromethylation of acrylamides with TMSCF3 is described.A wide range of arenes and heteroarenes at theβ-position of acrylamides are compatible with the reaction,affording the corresponding(E)-trifluoromethylated products in moderate to good yields.The reaction proceeded fast and can be completed within 30 min.展开更多
Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene （NHC）-supported Cu~ trifiuor- omethyl complexes. Four pr...Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene （NHC）-supported Cu~ trifiuor- omethyl complexes. Four proposed reaction pathways, namely cr-bond metathesis （BM）, concerted oxidative addition-reductive elimination （OARE）, iodine atom transfer （IAT） and single-electron transfer （SET）, have been computed by density functional theory （DFT）. The result indicated that the concerted OARE mechanism is favored among the four reaction pathways, suggesting the trifluoromethylation may occur via concerted OARE mechanism involving Ar-X oxidative addition to the Cu（1） center as the rate determining step.展开更多
The nucleophilic trifluoromethylation involving trifluoromethyllithium(LiCF_(3))species has been an open question since Haszeldine attempted to prepare LiCF_(3) in 1949.Indeed,LiCF_(3) has been used for electrophilic ...The nucleophilic trifluoromethylation involving trifluoromethyllithium(LiCF_(3))species has been an open question since Haszeldine attempted to prepare LiCF_(3) in 1949.Indeed,LiCF_(3) has been used for electrophilic difluoromethylene transfer processes(via elimination of fluoride ions)since 2010.Herein,we demonstrated that by using a polar solvent such as dimethylformamide(DMF)or hexamethylphosphoramide(HMPA)as the lithium chelator,the in situ deprotonation of fluoroform(HCF_(3))with lithium hexamethyldisilazide(LiHMDS)could generate a tamed LiCF_(3) species that is sufficiently persistent to undergo nucleophilic trifluoromethylation reaction.The nucleophilic reactivity of LiCF_(3) species was probed with several electrophiles,including arylsulfonyl fluorides,diaryl ketones,and silyl chlorides.The synthetic utility of this method is demonstrated with the efficient synthesis of highly valuable triflones that are otherwise difficult to synthesize from HCF_(3) using potassium or sodium bases.This work not only showcases a new protocol for the utilization of fluoroform(an industrial waste with high global warming potential)as the trifluoromethylation reagent,but also provides intriguing insights into the harnessing of nucleophilic reactivity of the transient LiCF_(3) species.展开更多
A simple copper-promoted one-pot Sandmeyer trifluoromethylation of aromatic amines with Langlois＇ reagent has been demonstrated. The reaction is performed in mild reaction conditions under an air atmosphere with good...A simple copper-promoted one-pot Sandmeyer trifluoromethylation of aromatic amines with Langlois＇ reagent has been demonstrated. The reaction is performed in mild reaction conditions under an air atmosphere with good substrate scope and functional group compatibility. It provides an alternative and straightforward synthetic approach to access a variety of trifluoromethylated arenes.展开更多
An efficient method for Cu-catalyzed decarboxylative trifluoromethylation offl-ketoacids to achieve a-trifluoro- methyl ketones was developed. A wide variety of synthetically useful α-trifluoromethyl ketones were obt...An efficient method for Cu-catalyzed decarboxylative trifluoromethylation offl-ketoacids to achieve a-trifluoro- methyl ketones was developed. A wide variety of synthetically useful α-trifluoromethyl ketones were obtained in modest to good yields under mild reaction conditions. The present method also exhibits good functional-group compatibility.展开更多
A novel iodonium-ylide compound 2 that appends a trifluoromethylthio （SCF3） group is disclosed as a new, shelf-stable electrophilic trifluoromethylation reagent. Unlike known shelf-stable electrophilic trifluorometh...A novel iodonium-ylide compound 2 that appends a trifluoromethylthio （SCF3） group is disclosed as a new, shelf-stable electrophilic trifluoromethylation reagent. Unlike known shelf-stable electrophilic trifluoromethylation reagents, 2 has a stable SCF3 group which is activated by appending iodonium ylide under copper catalysis via sul- fonium ylide to generate a cationic trifluoromethyl （CF3） species. Reagent 2 was found to be an efficient electro- philic trifluoromethylation reagent for a wide range of silyl enol ethers 3 under copper catalysis. Cyclic and acyclic a-trifiuoromethyl ketones 4 were obtained by reagent 2 in moderate to good yields. On the other hand, a difluoro- methylthio analogue 5 did not affect intermolecular transfer difluoromethylation to substrates. Instead, intramolecu- lar 1,4-migration proceeded similar to the Stevens rearrangement to provide 6 in 21% yield, independent of the presence of nucleophiles 3.展开更多
Trifluoromethyl group is one of the most frequently available and promising functional groups in pharmaceutical,agrochemical as well as material molecules.Developing synthetic methods for the synthesis of trifluoromet...Trifluoromethyl group is one of the most frequently available and promising functional groups in pharmaceutical,agrochemical as well as material molecules.Developing synthetic methods for the synthesis of trifluoromethyl functionalized compounds by trifluoromethylation reactions occupies significant position in modern organic chemistry.On the other hand,as a typical tool of sustainable synthesis,transition metal-free synthesis possesses unique advantages in atom economy,easy product purification as well as excellent eco-tolerance.Consequently,transition metal-free trifluoromethylation reactions constitute the most important approaches for accessing trifluoromethylated molecules.Herein,the advances in the transition metal-free C—H trifluoromethylation reactions are reviewed for the first time.According to the updated state-of-art,both the catalytic reactions by conventional heating chemistry and the more sustainable photocatalysis are included,covering the trifluoromethylation reactions of C(sp^(3))–H bond,aromatic C(sp^(2))–H bond as well as the non-aromatic C(sp^(2))–H bond in different substrates over the last five years(2017—2021).展开更多
DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide （DFPB） in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonat...DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide （DFPB） in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P＋CF2 , but also converts the difluorocarbene generated from ylide Ph3P＋CF2- into trifiuoromethyl anion, finally resulting in the trifluoromethy- lation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.展开更多
An efficient and practical method is developed for the trifluoromethylation of enamides using Umemoto's reagent as the trifluoromethylating reagent. These reactions proceeded under visible light irradiation withou...An efficient and practical method is developed for the trifluoromethylation of enamides using Umemoto's reagent as the trifluoromethylating reagent. These reactions proceeded under visible light irradiation without any photocatalyst at room temperature in good chemical yields.展开更多
Difluoromethylene phosphobetaine(Ph_(3)P^(+)CF_(2)CO_(2)^(-),PDFA),a known difluorocarbene reagent,was found to be able to efficiently trifluoromethylate terminal alkynes in the presence of Cu(I)and potassium fluoride...Difluoromethylene phosphobetaine(Ph_(3)P^(+)CF_(2)CO_(2)^(-),PDFA),a known difluorocarbene reagent,was found to be able to efficiently trifluoromethylate terminal alkynes in the presence of Cu(I)and potassium fluoride.The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields.展开更多
Summary of main observation and conclusion An efficient and environmentally benign electrochemical oxidative radical C-H trifluoromethylation of arenes by employing Langlois reagent as the CF3 source was developed in ...Summary of main observation and conclusion An efficient and environmentally benign electrochemical oxidative radical C-H trifluoromethylation of arenes by employing Langlois reagent as the CF3 source was developed in this work.Neither transition metal catalysts nor external chemical oxidants were required in this trifluoromethylation process.The reaction could be conducted in gram scale with high reaction efficiency.展开更多
The copper-mediated trifluoromethylation of terminal alkynes with S-（trifluoromethyl）diarylsulfonium salt has been carefully investigated. The reactions proceeded smoothly to afford trifluoromethylated acetylenes in...The copper-mediated trifluoromethylation of terminal alkynes with S-（trifluoromethyl）diarylsulfonium salt has been carefully investigated. The reactions proceeded smoothly to afford trifluoromethylated acetylenes in moderate to good yields. This approach is a convenient method to synthesize a variety of functional trifluoromethylated acetylenes.展开更多
Degradation of the highly reactive hypervalent trifluoromethylation iodine reagent PhI（OAc）（CF3）, which can only be generated in situ with mixing PhI（OAc）2 and TMSCF3 in the presence of CsF, was studied by ESI-M...Degradation of the highly reactive hypervalent trifluoromethylation iodine reagent PhI（OAc）（CF3）, which can only be generated in situ with mixing PhI（OAc）2 and TMSCF3 in the presence of CsF, was studied by ESI-MS and GC-MS combined with ~9F-NMR. The important transient intermediate PhlCF3＋ was determined by ESI-MS, and the major volatile products containing CF3 were identified with the authentic compounds by using GC-MS, such as trifluoromethylbenzene, 2-iodobenzotrifluoride, 3-iodobenzotrifluoride, 4-iodobenzotrifluoride. Meanwhile, more evidences obtained with 19F-NMR were given for such degradation reaction. A possible rapid CF3 radical transfer reaction pathway was proposed to clarify such degradation progress based on the experimental results. Therefore, this study may be helpful in elucidating the intrinsic reactivity of PhI（OAc）（CF3） and the possible competing side reactions caused by such self-degradation pathway.展开更多
Iodomethane is usually used as an electrophilic methylation reagent.Herein,we report its use as a C1 organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines in the absence of a transition meta...Iodomethane is usually used as an electrophilic methylation reagent.Herein,we report its use as a C1 organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines in the absence of a transition metal.Trifluoroacetic acid(TFA)was employed as an inexpensive,readily available trifluoromethyl source.The reaction efficiently produced a variety of trifluoromethylation products,with good functional group compatibility.Pyridine-containing drug molecules could also be selectively trifluoromethylated for late-stage functionalizations.Mechanistic studies showed that iodomethane selectively reacted with the pyridine starting material,rather than the pyridine product,to generate the corresponding N-methylpyridinium iodide.The decarboxylation of trifluoroacetic acid produced a trifluoromethyl anion,which added to the methylpyridinium iodide,and the subsequent aerobic rearomatization led to the generation of the ortho-trifluoromethylated product.展开更多
Professor Chaozhong Li's research group has long been interested in radicals in organic synthesis. They have developed a series of silver-catalyzed radical fluorination reactions since the year 2012.[1] In 2015, t...Professor Chaozhong Li's research group has long been interested in radicals in organic synthesis. They have developed a series of silver-catalyzed radical fluorination reactions since the year 2012.[1] In 2015, the research group joined the Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences. I joined the Li group in the same year.展开更多
文摘A photoinduced intramolecular charge transfer complex(ICTC)-enabled photoreduction of trifluoromethyl phosphonium salt for the trifluoromethylation of heteroarenes was developed.It offers a convenient approach to introduce trifluoromethyl group to a wide range of aromatic heterocycles,such as indoles,pyrrole,substituted benzene,coumarin,and chromone.This strategy provides operational simplicity,photocatalyst-,transition metal-,and oxidant-free conditions,making it highly advantageous.
基金the financial support provided by the National Natural Science Foundation of China(22361142832,92156025,22271212)the Science and Technology Project of Hebei Education Department Foundation(BJ2025192)We would like to thank Dr.Guosheng Ding,Dr.Kongying Zhu,and Dr.Xiaojuan Deng at the Analysis and Testing Center of Tianjin University for their assistance with NMR testing and analysis.
文摘The transition metal-free chalcogen trifluoromethylation of alkenes represents a highly efficient transformation for the rapid generation of C(sp3)-rich aliphatic trifluoromethyl compounds. However, a unified methodology to achieve oxy-, thio-, and seleno-trifluoromethylation remains elusive yet highly desirable. In this study, we report a triarylamine-catalyzed three-component vicinal chalcogen-trifluoromethylation of alkenes under blue light irradiation without the need of transition metal catalyst. This reaction is broadly applicable to oxy, thio, and seleno nucleophiles, facilitating modular access to a diverse array of β-trifluoromethyl alcohols, ethers, thioethers, thiocyanates, and selenocyanates with good yields and predictable regioselectivities (61 examples). Additionally, we demonstrate its application in the late-stage modification of natural products and pharmaceutical compounds. Preliminary mechanistic studies suggest that a catalytic electron donor-acceptor (EDA) complex between triarylamine and the Umemoto reagent is key to enabling the radical/polar crossover process.
基金supported by the Natural Science Foundation of Shanghai(No.20ZR1471600)the Science and Technology Commission of Shanghai Municipality(No.19DZ2271100)the Open Research Fund Program of CAS Key Laboratory of Energy Regulation Materials(No.ORFP2020–06)。
文摘A new electrochemical strategy for trifluoromethylation/cyclization using TfNHNHBoc as a CF_(3)source was established.This approach was realized by the direct electrolysis of Tf NHNHBoc under external oxidantfree and catalyst-free conditions,and afforded various trifluoromethylated oxindoles with good functional group compatibility and broad substrate scope.Preliminary mechanistic studies show that the reaction proceeds by a radical process.
基金financially supported by the National Natural Science Foundation of China(Nos.21977075,22271200,21801178,21907070,81971653)1.3.5 Project for Disciplines of Excellence,West China Hospital,Sichuan University,Central Plains Science and Technology Innovation Leader Project(No.214200510008 to L.Li)Scientific and Technological Innovation Team of Colleges and Universities in Henan Province(No.21IRTSTHN001)。
文摘Difluorocarbene has emerged as a valuable intermediate to synthesize fluorides.However,difluorocarbene-derived synthesis of^(19)F/^(18)F-trifluoromethyl triazoles has not been explored.Herein,we reported the Cu(I)-promoted difluorocarbene-derived^(19)F/^(18)F-trifluoromethylation of iodotriazoles using KF/K^(18)F as the fluorine source.This approach rapidly generated a wide range of 5-trifluoromethyl-1,2,3-triazoles in good yields showing high functional group compatibility.The reaction was effective for late-stage functionalization of bioactive molecules and^(18)F-trifluoromethylation of iodotriazoles.This work provides a practical synthetic methodology for the development of triazole drugs and^(18)F-radiotracers for positron emission tomography.
文摘In the presence of copper （I） halide as catalyst, a variety of carbonyl compounds could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields.
基金the National Natural Science Foundation of China(Nos.21472211,21502212,21772211)Youth Innovation Promotion Association CAS(Nos.2014229 and2018293)+1 种基金Institutes for Drug Discovery and Development,Chinese Academy of Sciences(No.CASIMM 0120163006)Science and Technology Commission of Shanghai Municipality(No.17JC1405000)for financial support
文摘A copper-catalyzedα-selective C–H trifluoromethylation of acrylamides with TMSCF3 is described.A wide range of arenes and heteroarenes at theβ-position of acrylamides are compatible with the reaction,affording the corresponding(E)-trifluoromethylated products in moderate to good yields.The reaction proceeded fast and can be completed within 30 min.
基金supported by National Natural Science Foundation of China(Nos.21073144,21173169)Fundamental Research Funds for the Central Universities(No.XDJK2013A008)
文摘Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene （NHC）-supported Cu~ trifiuor- omethyl complexes. Four proposed reaction pathways, namely cr-bond metathesis （BM）, concerted oxidative addition-reductive elimination （OARE）, iodine atom transfer （IAT） and single-electron transfer （SET）, have been computed by density functional theory （DFT）. The result indicated that the concerted OARE mechanism is favored among the four reaction pathways, suggesting the trifluoromethylation may occur via concerted OARE mechanism involving Ar-X oxidative addition to the Cu（1） center as the rate determining step.
基金support of this work by the National Key Research and Development Program of China(2021YFF0701700)the National Natural Science Foundation of China(22271299,22261132514 and 22301308)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0590000)the Natural Science Foundation of Shandong Province(ZR2021LFG006 and ZR2023LFG003)the Shandong Dongyue Polymer Material Co.Ltd.is gratefully acknowledged。
文摘The nucleophilic trifluoromethylation involving trifluoromethyllithium(LiCF_(3))species has been an open question since Haszeldine attempted to prepare LiCF_(3) in 1949.Indeed,LiCF_(3) has been used for electrophilic difluoromethylene transfer processes(via elimination of fluoride ions)since 2010.Herein,we demonstrated that by using a polar solvent such as dimethylformamide(DMF)or hexamethylphosphoramide(HMPA)as the lithium chelator,the in situ deprotonation of fluoroform(HCF_(3))with lithium hexamethyldisilazide(LiHMDS)could generate a tamed LiCF_(3) species that is sufficiently persistent to undergo nucleophilic trifluoromethylation reaction.The nucleophilic reactivity of LiCF_(3) species was probed with several electrophiles,including arylsulfonyl fluorides,diaryl ketones,and silyl chlorides.The synthetic utility of this method is demonstrated with the efficient synthesis of highly valuable triflones that are otherwise difficult to synthesize from HCF_(3) using potassium or sodium bases.This work not only showcases a new protocol for the utilization of fluoroform(an industrial waste with high global warming potential)as the trifluoromethylation reagent,but also provides intriguing insights into the harnessing of nucleophilic reactivity of the transient LiCF_(3) species.
基金We acknowledge the financial support for this work from the National Natural Science Foundation of China （Nos. 21502070 and 21562041） and the Fundamental Research Funds for the Central Universities （No. JUSRP51626B）.
文摘A simple copper-promoted one-pot Sandmeyer trifluoromethylation of aromatic amines with Langlois＇ reagent has been demonstrated. The reaction is performed in mild reaction conditions under an air atmosphere with good substrate scope and functional group compatibility. It provides an alternative and straightforward synthetic approach to access a variety of trifluoromethylated arenes.
基金We gratefully acknowledge financial support from the National Natural Science Foundation of China （21472033） and the Fundamental Research Funds for the Central Universities. We thank Wen-Man Zhang and Bei Huang in this group for reproducing the results of compounds 3c, 3e, and 3m.
文摘An efficient method for Cu-catalyzed decarboxylative trifluoromethylation offl-ketoacids to achieve a-trifluoro- methyl ketones was developed. A wide variety of synthetically useful α-trifluoromethyl ketones were obtained in modest to good yields under mild reaction conditions. The present method also exhibits good functional-group compatibility.
文摘A novel iodonium-ylide compound 2 that appends a trifluoromethylthio （SCF3） group is disclosed as a new, shelf-stable electrophilic trifluoromethylation reagent. Unlike known shelf-stable electrophilic trifluoromethylation reagents, 2 has a stable SCF3 group which is activated by appending iodonium ylide under copper catalysis via sul- fonium ylide to generate a cationic trifluoromethyl （CF3） species. Reagent 2 was found to be an efficient electro- philic trifluoromethylation reagent for a wide range of silyl enol ethers 3 under copper catalysis. Cyclic and acyclic a-trifiuoromethyl ketones 4 were obtained by reagent 2 in moderate to good yields. On the other hand, a difluoro- methylthio analogue 5 did not affect intermolecular transfer difluoromethylation to substrates. Instead, intramolecu- lar 1,4-migration proceeded similar to the Stevens rearrangement to provide 6 in 21% yield, independent of the presence of nucleophiles 3.
基金supported by the Natural Science Foundation of Jiangxi Province(20202ACBL203006).
文摘Trifluoromethyl group is one of the most frequently available and promising functional groups in pharmaceutical,agrochemical as well as material molecules.Developing synthetic methods for the synthesis of trifluoromethyl functionalized compounds by trifluoromethylation reactions occupies significant position in modern organic chemistry.On the other hand,as a typical tool of sustainable synthesis,transition metal-free synthesis possesses unique advantages in atom economy,easy product purification as well as excellent eco-tolerance.Consequently,transition metal-free trifluoromethylation reactions constitute the most important approaches for accessing trifluoromethylated molecules.Herein,the advances in the transition metal-free C—H trifluoromethylation reactions are reviewed for the first time.According to the updated state-of-art,both the catalytic reactions by conventional heating chemistry and the more sustainable photocatalysis are included,covering the trifluoromethylation reactions of C(sp^(3))–H bond,aromatic C(sp^(2))–H bond as well as the non-aromatic C(sp^(2))–H bond in different substrates over the last five years(2017—2021).
文摘DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide （DFPB） in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P＋CF2 , but also converts the difluorocarbene generated from ylide Ph3P＋CF2- into trifiuoromethyl anion, finally resulting in the trifluoromethy- lation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.
基金supported by the National Natural Science Foundation of China(2147208481421091)+2 种基金the Qing Lan Project of Jiangsu Province and State Key Laboratory of Bioorganic & Natural Products ChemistryShanghai Institute of Organic ChemistryChinese Academy of Sciences
文摘An efficient and practical method is developed for the trifluoromethylation of enamides using Umemoto's reagent as the trifluoromethylating reagent. These reactions proceeded under visible light irradiation without any photocatalyst at room temperature in good chemical yields.
基金The authors thank the National Natural Science Foundation of China(NSFC)(Nos.21032006,21172240)the 973 Program of China(No.2012CBA01200)the Chinese Academy of Sciences for financial support.
文摘Difluoromethylene phosphobetaine(Ph_(3)P^(+)CF_(2)CO_(2)^(-),PDFA),a known difluorocarbene reagent,was found to be able to efficiently trifluoromethylate terminal alkynes in the presence of Cu(I)and potassium fluoride.The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields.
基金supported by the National Natural Science Foundation of China (No.21702081)Jiangxi Provincial Education Department Foundation (No.GJJ160325).
文摘Summary of main observation and conclusion An efficient and environmentally benign electrochemical oxidative radical C-H trifluoromethylation of arenes by employing Langlois reagent as the CF3 source was developed in this work.Neither transition metal catalysts nor external chemical oxidants were required in this trifluoromethylation process.The reaction could be conducted in gram scale with high reaction efficiency.
基金Acknowledgement We thank the National Natural Science Foundation of China （Nos. 21032006, 21172240）, the 973 Program of China （No. 2012CBA01200）, the Chinese Academy of Sciences for financial support.
文摘The copper-mediated trifluoromethylation of terminal alkynes with S-（trifluoromethyl）diarylsulfonium salt has been carefully investigated. The reactions proceeded smoothly to afford trifluoromethylated acetylenes in moderate to good yields. This approach is a convenient method to synthesize a variety of functional trifluoromethylated acetylenes.
基金The authors are grateful for financial supports from the National Natural Science Foundation of China （NSFC Grant Nos. 21475145 and 21472228） and Youth Innovation Promotion Association CAS （201317 !）.
文摘Degradation of the highly reactive hypervalent trifluoromethylation iodine reagent PhI（OAc）（CF3）, which can only be generated in situ with mixing PhI（OAc）2 and TMSCF3 in the presence of CsF, was studied by ESI-MS and GC-MS combined with ~9F-NMR. The important transient intermediate PhlCF3＋ was determined by ESI-MS, and the major volatile products containing CF3 were identified with the authentic compounds by using GC-MS, such as trifluoromethylbenzene, 2-iodobenzotrifluoride, 3-iodobenzotrifluoride, 4-iodobenzotrifluoride. Meanwhile, more evidences obtained with 19F-NMR were given for such degradation reaction. A possible rapid CF3 radical transfer reaction pathway was proposed to clarify such degradation progress based on the experimental results. Therefore, this study may be helpful in elucidating the intrinsic reactivity of PhI（OAc）（CF3） and the possible competing side reactions caused by such self-degradation pathway.
基金supported by the National Natural Science Foundation of China(21971093)the Fundamental Research Funds for the Central Universities(lzujbky-2021-sp53)+1 种基金the International Joint Research Centre for Green Catalysis and Synthesis(2016B01017)the 111 Project。
文摘Iodomethane is usually used as an electrophilic methylation reagent.Herein,we report its use as a C1 organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines in the absence of a transition metal.Trifluoroacetic acid(TFA)was employed as an inexpensive,readily available trifluoromethyl source.The reaction efficiently produced a variety of trifluoromethylation products,with good functional group compatibility.Pyridine-containing drug molecules could also be selectively trifluoromethylated for late-stage functionalizations.Mechanistic studies showed that iodomethane selectively reacted with the pyridine starting material,rather than the pyridine product,to generate the corresponding N-methylpyridinium iodide.The decarboxylation of trifluoroacetic acid produced a trifluoromethyl anion,which added to the methylpyridinium iodide,and the subsequent aerobic rearomatization led to the generation of the ortho-trifluoromethylated product.
文摘Professor Chaozhong Li's research group has long been interested in radicals in organic synthesis. They have developed a series of silver-catalyzed radical fluorination reactions since the year 2012.[1] In 2015, the research group joined the Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences. I joined the Li group in the same year.
