Linear alkyl benzenes （LABs） are the main materials for detergent production. The presence of aromatic compounds in this material can decrease the quality of the final product and enhance the deactivation rate of ca...Linear alkyl benzenes （LABs） are the main materials for detergent production. The presence of aromatic compounds in this material can decrease the quality of the final product and enhance the deactivation rate of catalysts. In this research we used zeolite NaX for de-aromatization of the recycled paraffin from the alkylation unit of an LAB production complex. The effect of different parameters on the removal efficiency of adsorbent was studied and optimized. To study the re-usability of the adsorbent, the breakthrough curves were obtained by using a fixed bed column filled with the adsorbent. The results indicated that the adsorbent capacity remained unchanged after three regeneration cycles. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. It was concluded that the Langmuir model agreed well with the experimental data. The calculated thermodynamic parameters of the adsorption showed that the adsorption process was spontaneous and exothermic. The reaction rate was estimated by the pseudo-second order kinetic model.展开更多
We report herein a palladium-catalyzed diarylative dearomatization of indole by employing thioester and arylboronic acid as the aryl electrophiles.The reaction involved a decarbonylation/migratory insertion/terminal S...We report herein a palladium-catalyzed diarylative dearomatization of indole by employing thioester and arylboronic acid as the aryl electrophiles.The reaction involved a decarbonylation/migratory insertion/terminal Suzuki coupling procedure.Substrates bearing various functional groups are well tolerated in the reaction,affording the diarylated indoline skeletons in moderate to good yields.展开更多
A catalytic asymmetric hydroxylative dearomatization reaction has been disclosed,and the products can smoothly transform into spiroannulation adducts by simply treated with a base under mild conditions.Novel in-situ g...A catalytic asymmetric hydroxylative dearomatization reaction has been disclosed,and the products can smoothly transform into spiroannulation adducts by simply treated with a base under mild conditions.Novel in-situ generated magnesium catalytic methods are developed by application of combinational ligands.Related concise transformaitons of the spiroannulation adducts have been carried out.展开更多
Photo‐catalyzed tandem dearomatization/carboxylation of benzyl o‐halogenated aryl ether with CO_(2) was achieved,which affords spirocyclic carboxylic acids under mild conditions.The reaction has good functional grou...Photo‐catalyzed tandem dearomatization/carboxylation of benzyl o‐halogenated aryl ether with CO_(2) was achieved,which affords spirocyclic carboxylic acids under mild conditions.The reaction has good functional group tolerance with high yields.Mechanism studies indicate that the transformation was realized via intramolecular radical addition and nucleophilic addition.展开更多
The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in a...The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in aqueous solution.The resultant 2,3-diazides can be smoothly converted to other functional groups,including vicinal diamines,triazoles and benzotriazoles,in a single step.展开更多
Atom-and step-economy in IBX assisted diversity-oriented synthesis is achieved with a versatile AQ auxiliary α-amino acid analogs offering rapid access to polycyclic spiro-quinolines featuring a quaternary stereocent...Atom-and step-economy in IBX assisted diversity-oriented synthesis is achieved with a versatile AQ auxiliary α-amino acid analogs offering rapid access to polycyclic spiro-quinolines featuring a quaternary stereocenter in 20%–91% yields under mild conditions via 7,8-dearomatization of quinolines. Free of a preinstalled activation group is highlight of this intramolecular oxidation spiroannulation tandem reaction. This type of N-heterospirocycles, traditionally difficult to access, may open the door to a potentially interest scaffold for synthetic and medicinal chemistry.展开更多
Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral ...Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Br■nsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities.展开更多
A straightforward and efficient protocol for dearomatizing indoles is described.The reaction,catalyzed by an inexpensive Co(III)/Zn(II)catalyst,starts from easily accessible N‐pyrimidinyl indoles and ene‐yne ketones...A straightforward and efficient protocol for dearomatizing indoles is described.The reaction,catalyzed by an inexpensive Co(III)/Zn(II)catalyst,starts from easily accessible N‐pyrimidinyl indoles and ene‐yne ketones.Mild reaction conditions,high diastereoselectivity,a broad substrate scope,effective functional group tolerance,and reasonable to remarkable yields were observed.展开更多
A catalytic asymmetric brominative dearomatization reaction of benzofuran derivatives was achieved by using hydroquinidine 1,4-phthalazinediyl diether [（DHQ）_2PHAL] as the catalyst and N-bromoacetamide（NBAc） as th...A catalytic asymmetric brominative dearomatization reaction of benzofuran derivatives was achieved by using hydroquinidine 1,4-phthalazinediyl diether [（DHQ）_2PHAL] as the catalyst and N-bromoacetamide（NBAc） as the brominating reagent. A series of brominated spiro[benzofuran-2,5＇-oxazoles] bearing two contiguous stereogenic centers were obtained in high yields（up to 99%） with excellent enantioselectivity（up to 97% ee）.展开更多
1,7-Hydride transfer-involved dearomatization of quinolines toward C3-spiro hydroquinoline derivatives has been developed.This method offers a protocol to achieve the dearomatization of electron-deficient arenes via t...1,7-Hydride transfer-involved dearomatization of quinolines toward C3-spiro hydroquinoline derivatives has been developed.This method offers a protocol to achieve the dearomatization of electron-deficient arenes via the redox-neutral hydride transfer process.A series of C3-spiro hydroquinolines can be provided in moderate to excellent yields(up to 98%)with good diastereoselectivities.Significant advantages such as high step-and atomeconomy,as well as redox-neutral and mild conditions,make it an appealing alternative to achieve the dearomatization of quinolines.展开更多
The dearomatization of indole derivatives bearing amide functionalities presents a significant challenge due to the inherent stability of the amide carbonyl group,resulting from nitrogen lone-pair delocalization that ...The dearomatization of indole derivatives bearing amide functionalities presents a significant challenge due to the inherent stability of the amide carbonyl group,resulting from nitrogen lone-pair delocalization that imparts increased resonance stabilization.In this study,we report a visible-light photocatalytic intramolecular dearomatization of indole derivatives with amide groups,achieving the synthesis of spiroindolines via energy transfer.This method enables the efficient formation of a range of hydroxyl-substituted spiroindolines in moderate to high yields,with excellent diastereoselectivity(>20:1)under mild reaction conditions.Control experiments confirmed the involvement of an energy transfer pathway in the reaction mechanism.Density Functional Theory(DFT)calculations further revealed r-stacking interactions between the indole core and pyridine ring,along with the strengthening of hydrogen bonding between the pyridine nitrogen and hexafluoroisopropanol(HFiP)in the excited state.These interactions facilitated the energy transfer-mediated triplet excited state intermolecular proton transfer(T-ESPT),crucial for activating the otherwise amide functionality.This protocol represents a rare example of harnessing the reactivity of amide groups for dearomative transformations.展开更多
Chiral[2.2]paracyclophane(PCP)is an intriguing prevalent scaffold widely utilized inπ-stacked polymers,luminescent materials,and asymmetric catalysis.However,current synthetic methods to access chiral PCP derivatives...Chiral[2.2]paracyclophane(PCP)is an intriguing prevalent scaffold widely utilized inπ-stacked polymers,luminescent materials,and asymmetric catalysis.However,current synthetic methods to access chiral PCP derivatives are still limited to physical separation and chemical or kinetic resolution.The direct desymmetric functionalization of nonsubstituted PCP has been a challenge since its discovery 70 years ago.Herein,we present a catalytic desymmetric dearomatization cyclopropanation reaction of PCP,providing rapid access to enantioenriched PCP cyclopropyl carboxylates with continuous tertiary/quaternary/quaternary chiral centers.The application of the chiral PCPs obtained has also been demonstrated by transformation to structurally novel C_(2) symmetric dirhodium catalysts.Of equal importance,detailed density functional theory calculations have been carried out to reveal the mechanism of this reaction.The key to this success is a structurally symmetric bulky C_(4) dirhodium catalyst:noncovalent interactions exist between substrates and catalysts,which form a cavity to host substrates,and mainly affect the regio-and enantioselectivity.展开更多
A dearomatization strategy using dicetolic acid(6)as the starting material to synthesize the core intermediate(10R,13S,14S)-10,13-dimethyl-7,10,11,12,13,14,15,16-octahydro-3H-cyclopenta[a]phenanthrene-3,17(6H)-dione(2...A dearomatization strategy using dicetolic acid(6)as the starting material to synthesize the core intermediate(10R,13S,14S)-10,13-dimethyl-7,10,11,12,13,14,15,16-octahydro-3H-cyclopenta[a]phenanthrene-3,17(6H)-dione(20)for the formal synthesis of dydrogesterone is presented,achieving a total yield of 21%over nine steps.This approach features an environmentally friendly carbonyl protection strategy and efficient Heck coupling,while avoiding harsh conditions and hazardous reagents throughout the entire process.展开更多
Catalytic asymmetric dearomatization(CADA)of phenols has emerged as a powerful strategy for constructing stereochemically complicated architectures from planar aromatic feedstocks.However,the development of novel cata...Catalytic asymmetric dearomatization(CADA)of phenols has emerged as a powerful strategy for constructing stereochemically complicated architectures from planar aromatic feedstocks.However,the development of novel catalysts for highly enantioselective phenolic oxidative dearomatization continues to be a time-and resource-intensive endeavor,attributable mainly to the paucity of a reliable predictive catalyst design strategy.In this study,we systematically compiled a dataset of 847 literaturereported asymmetric phenolic dearomatization by hypervalent iodine(III)catalysts(HVI-CADA dataset),a unique type of catalyst that is gaining increasing attention owing to their ecofriendly features.Leveraging this reaction dataset,we established a machine learning predictive model to predict enantioselectivity.The XGBoost algorithm exhibited the optimal performance,with a root-mean-square error of 0.26(kcal/mol)and an R^(2)of 0.84.This established model can effectively guide the selection of the optimal catalyst and additives in out-of-sample tests.Subsequent independent experiments were conducted to validate the results obtained from the model predictions.We anticipate that our current work will facilitate further design,optimization,and development of novel chiral hypervalent iodine catalysts for new asymmetric phenolic dearomatization reactions.展开更多
We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds ...We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.展开更多
Herein,we achieved a green and efficient dearomatization for the synthesis of 2,3-functionalized polycyclic indolines in an electrochemical way.This avoiding of external oxidants and metals approach allowed various nu...Herein,we achieved a green and efficient dearomatization for the synthesis of 2,3-functionalized polycyclic indolines in an electrochemical way.This avoiding of external oxidants and metals approach allowed various nucleophilic sources(Nu¼anilines,TMSN3 and ROH)to perform the products,representing an environmentally benign means.Additionally,the continuous flow electrosynthesis and synthetic transformations also reveal the strong practicality of electrochemistry in organic synthesis.展开更多
P450 enzymes-catalyzed aromatic hydroxylation plays an important role in detoxification,biosynthesis,and potential carcinogenic effect of aromatic compounds.Though it has been explored for decades,the actual process o...P450 enzymes-catalyzed aromatic hydroxylation plays an important role in detoxification,biosynthesis,and potential carcinogenic effect of aromatic compounds.Though it has been explored for decades,the actual process of aromatic hydroxylation and mechanism of regioselectivity catalyzed by cytochrome P450 monooxygenases remained ambiguous.Here,we have resolved these issues.With a stable chiral organofluorine probe,and especially with X-ray data of two isolated arene oxides derivatives,we demonstrate that an arene oxide pathway is definitely involved in P450-catalyzed aromatic hydroxylation.By the capture,isolation,identification and reactivity exploration of the arene 1,2-oxide and arene 2,3-oxide intermediates,together with advanced QM calculations,the mechanism of how two intermediates go to the same product has been elucidated.In addition to the model substrate,we also confirmed that an arene oxide intermediate is involved in the P450-catalyzed hydroxylation pathway of a natural product derivative methyl cinnamate,which indicates that this intermediate appears to be universal in P450-catalyzed aromatic hydroxylation.Our work not only provides the most direct evidence for the arene oxide pathway and new insights into the regioselectivity involved in P450-catalyzed aromatic hydroxylation,but also supplies a new synthetic approach to achieve the dearomatization of aromatic compounds.展开更多
The first total synthesis of(+)-taberdicatine B and(+)-tabernabovine B has been accomplished in 10steps with 26.9% overall yield and 15 steps with 7.3% overall yield,respectively.The prominent features of this efficie...The first total synthesis of(+)-taberdicatine B and(+)-tabernabovine B has been accomplished in 10steps with 26.9% overall yield and 15 steps with 7.3% overall yield,respectively.The prominent features of this efficient synthetic strategy include the following:(1)(+)-Taberdicatine B and(+)-tabernabovine B were accessed from common advanced intermediates by varying the substituents;(2) A one-pot asymmetric bromocyclization/hydrolysis was explored to assemble HPI skeleton;(3) Dieckmann condensation to form β-keto ester for the assembly of seven-membered ring;(4) An ester reduction/amide semireduction/cyclization sequence was applied to form the cage-like framework.展开更多
Catalytic asymmetric dearomatization(CADA)has emerged as a powerful strategy for transforming planar aromatic systems into three-dimensional chiral architectures[1].Notably,the Büchner reaction and arene cyclopro...Catalytic asymmetric dearomatization(CADA)has emerged as a powerful strategy for transforming planar aromatic systems into three-dimensional chiral architectures[1].Notably,the Büchner reaction and arene cyclopropanation excel in constructing complex polycyclic frameworks[2].However,current methods predominantly rely on diazo compounds as carbene precursors(Scheme1a),which pose safety risks and limit functional group compatibility.展开更多
An asymmetric fluorinative dearomatization reaction of tryptophol derivatives was developed via chiral anion phase-transfer catalysis. Vari- ous fluorinated furoindolines were obtained in moderate to excellent yields ...An asymmetric fluorinative dearomatization reaction of tryptophol derivatives was developed via chiral anion phase-transfer catalysis. Vari- ous fluorinated furoindolines were obtained in moderate to excellent yields and enantioselectivity in the presence of Selectfluor. The preliminary mecha- nistic studies suggested the existence of an in situ formed tryptophol boronic ester plays a critical role in determining the enantioselectivity. This method features the facile introduction of a fluorine atom in a highly enantioselective manner and construction of two contiguous quaternary stereogenic cen- ters.展开更多
基金Financial support of the Iran Chemical Industries Investment Company is greatly acknowledged
文摘Linear alkyl benzenes （LABs） are the main materials for detergent production. The presence of aromatic compounds in this material can decrease the quality of the final product and enhance the deactivation rate of catalysts. In this research we used zeolite NaX for de-aromatization of the recycled paraffin from the alkylation unit of an LAB production complex. The effect of different parameters on the removal efficiency of adsorbent was studied and optimized. To study the re-usability of the adsorbent, the breakthrough curves were obtained by using a fixed bed column filled with the adsorbent. The results indicated that the adsorbent capacity remained unchanged after three regeneration cycles. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. It was concluded that the Langmuir model agreed well with the experimental data. The calculated thermodynamic parameters of the adsorption showed that the adsorption process was spontaneous and exothermic. The reaction rate was estimated by the pseudo-second order kinetic model.
基金the Shanghai Institute of Materia Medicathe Chinese Academy of Sciences+4 种基金the National Natural Science Foundation of China(Nos.21772211 and 21920102003)the Youth Innovation Promotion Association CAS(Nos.2014229 and 2018293)the Science and Technology Commission of Shanghai Municipality(Nos.17JC1405000 and 18431907100)the Program of Shanghai Academic Research Leader(No.19XD1424600)the National Science&Technology Major Project“Key New Drug Creation and Manufacturing Program”,China(No.2018ZX09711002-006)for financial support。
文摘We report herein a palladium-catalyzed diarylative dearomatization of indole by employing thioester and arylboronic acid as the aryl electrophiles.The reaction involved a decarbonylation/migratory insertion/terminal Suzuki coupling procedure.Substrates bearing various functional groups are well tolerated in the reaction,affording the diarylated indoline skeletons in moderate to good yields.
基金the financial support from the National Natural Science Foundation of China (Nos. 21901092, 21807053)Innovation Fund for Medical Sciences (No. 2019-12M-5-074)+2 种基金Program for Chang-jiang Scholars and Innovative Research Team in University (PCSIRT) (No. IRT_15R27)the Funds for Fundamental Research Creative Groups of Gansu Province (No. 20JR5RA310)the Fundamental Research Funds for the Central Universities (Nos. lzujbky2020-49, 2021-kb21)
文摘A catalytic asymmetric hydroxylative dearomatization reaction has been disclosed,and the products can smoothly transform into spiroannulation adducts by simply treated with a base under mild conditions.Novel in-situ generated magnesium catalytic methods are developed by application of combinational ligands.Related concise transformaitons of the spiroannulation adducts have been carried out.
文摘Photo‐catalyzed tandem dearomatization/carboxylation of benzyl o‐halogenated aryl ether with CO_(2) was achieved,which affords spirocyclic carboxylic acids under mild conditions.The reaction has good functional group tolerance with high yields.Mechanism studies indicate that the transformation was realized via intramolecular radical addition and nucleophilic addition.
基金the National Natural Science Foundation of China(Nos.21472172,21272212)Natural Science Foundation of Zhejiang Province(No.LY17B060009)。
文摘The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in aqueous solution.The resultant 2,3-diazides can be smoothly converted to other functional groups,including vicinal diamines,triazoles and benzotriazoles,in a single step.
基金the National Natural Science Foundation of China (Nos. 22101074, 21877206, and 21772032)the 111 Project (No. D17007)+2 种基金Excellent Youth Foundation of Henan Scientific Committee (No. 222300420012)China Postdoctoral Science Foundation (No. 2019M660173)the Natural Science Foundation of Henan Province (No. 202300410233)。
文摘Atom-and step-economy in IBX assisted diversity-oriented synthesis is achieved with a versatile AQ auxiliary α-amino acid analogs offering rapid access to polycyclic spiro-quinolines featuring a quaternary stereocenter in 20%–91% yields under mild conditions via 7,8-dearomatization of quinolines. Free of a preinstalled activation group is highlight of this intramolecular oxidation spiroannulation tandem reaction. This type of N-heterospirocycles, traditionally difficult to access, may open the door to a potentially interest scaffold for synthetic and medicinal chemistry.
基金financial support from the National Natural Science Foundation of China(Nos.22125108,22101238,92056104 and 21772161)the China Postdoctoral Science Foundation(No.2020M680087)+3 种基金the Natural Science Foundation of Fujian Province of China(No.2019J02001)the President Research Funds from Xiamen University(No.20720210002)the Fundamental Research Funds for the Central Universities(No.20720202008)NFFTBS(No.J1310024)。
文摘Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Br■nsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities.
文摘A straightforward and efficient protocol for dearomatizing indoles is described.The reaction,catalyzed by an inexpensive Co(III)/Zn(II)catalyst,starts from easily accessible N‐pyrimidinyl indoles and ene‐yne ketones.Mild reaction conditions,high diastereoselectivity,a broad substrate scope,effective functional group tolerance,and reasonable to remarkable yields were observed.
基金the National Key R&D Program of China (No. 2016YFA0202900)National Basic Research Program of China (No.2015CB856600)+1 种基金the National Natural Science Foundation of China (Nos. 21332009, 21421091)the Chinese Academy of Sciences (Nos. XDB20000000, QYZDY-SSW-SLH012) for generous financial support
文摘A catalytic asymmetric brominative dearomatization reaction of benzofuran derivatives was achieved by using hydroquinidine 1,4-phthalazinediyl diether [（DHQ）_2PHAL] as the catalyst and N-bromoacetamide（NBAc） as the brominating reagent. A series of brominated spiro[benzofuran-2,5＇-oxazoles] bearing two contiguous stereogenic centers were obtained in high yields（up to 99%） with excellent enantioselectivity（up to 97% ee）.
基金support from the Taishan Scholars Construction Projects of Shandong(No.tsqn201909131)the National Natural Science Foundation of China(No.22001144)the Natural Science Foundation of Shandong Province(Nos.ZR2020QB046,ZR2020KB007 and ZR2020QB047).
文摘1,7-Hydride transfer-involved dearomatization of quinolines toward C3-spiro hydroquinoline derivatives has been developed.This method offers a protocol to achieve the dearomatization of electron-deficient arenes via the redox-neutral hydride transfer process.A series of C3-spiro hydroquinolines can be provided in moderate to excellent yields(up to 98%)with good diastereoselectivities.Significant advantages such as high step-and atomeconomy,as well as redox-neutral and mild conditions,make it an appealing alternative to achieve the dearomatization of quinolines.
基金supported by the National Natural Science Foundation of China(22001220)Sichuan Science and Technology Program(2023NSFSC1086)+1 种基金the Collaborative Fund of Luzhou Government and Southwest Medical University(2024LZXNYDJ016)Ningbo Key Scientific and Technological Project(2023ZI58)。
文摘The dearomatization of indole derivatives bearing amide functionalities presents a significant challenge due to the inherent stability of the amide carbonyl group,resulting from nitrogen lone-pair delocalization that imparts increased resonance stabilization.In this study,we report a visible-light photocatalytic intramolecular dearomatization of indole derivatives with amide groups,achieving the synthesis of spiroindolines via energy transfer.This method enables the efficient formation of a range of hydroxyl-substituted spiroindolines in moderate to high yields,with excellent diastereoselectivity(>20:1)under mild reaction conditions.Control experiments confirmed the involvement of an energy transfer pathway in the reaction mechanism.Density Functional Theory(DFT)calculations further revealed r-stacking interactions between the indole core and pyridine ring,along with the strengthening of hydrogen bonding between the pyridine nitrogen and hexafluoroisopropanol(HFiP)in the excited state.These interactions facilitated the energy transfer-mediated triplet excited state intermolecular proton transfer(T-ESPT),crucial for activating the otherwise amide functionality.This protocol represents a rare example of harnessing the reactivity of amide groups for dearomative transformations.
基金support of the Natural Science Foundation of China and Shandong Province(grant nos.21971149,92156007,21933003,ZR2019ZD45,and ZR2020KB005).
文摘Chiral[2.2]paracyclophane(PCP)is an intriguing prevalent scaffold widely utilized inπ-stacked polymers,luminescent materials,and asymmetric catalysis.However,current synthetic methods to access chiral PCP derivatives are still limited to physical separation and chemical or kinetic resolution.The direct desymmetric functionalization of nonsubstituted PCP has been a challenge since its discovery 70 years ago.Herein,we present a catalytic desymmetric dearomatization cyclopropanation reaction of PCP,providing rapid access to enantioenriched PCP cyclopropyl carboxylates with continuous tertiary/quaternary/quaternary chiral centers.The application of the chiral PCPs obtained has also been demonstrated by transformation to structurally novel C_(2) symmetric dirhodium catalysts.Of equal importance,detailed density functional theory calculations have been carried out to reveal the mechanism of this reaction.The key to this success is a structurally symmetric bulky C_(4) dirhodium catalyst:noncovalent interactions exist between substrates and catalysts,which form a cavity to host substrates,and mainly affect the regio-and enantioselectivity.
文摘A dearomatization strategy using dicetolic acid(6)as the starting material to synthesize the core intermediate(10R,13S,14S)-10,13-dimethyl-7,10,11,12,13,14,15,16-octahydro-3H-cyclopenta[a]phenanthrene-3,17(6H)-dione(20)for the formal synthesis of dydrogesterone is presented,achieving a total yield of 21%over nine steps.This approach features an environmentally friendly carbonyl protection strategy and efficient Heck coupling,while avoiding harsh conditions and hazardous reagents throughout the entire process.
基金supported by the Ministry of Science and Technology of China(grant no.2021YFF0701700)the National Natural Science Foundation of China(grant nos.22122104,22193012,and 21933004)+1 种基金the CAS Project for Young Scientists in Basic Research(grant nos.YSBR-052 and YSBR-095)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB0590000).
文摘Catalytic asymmetric dearomatization(CADA)of phenols has emerged as a powerful strategy for constructing stereochemically complicated architectures from planar aromatic feedstocks.However,the development of novel catalysts for highly enantioselective phenolic oxidative dearomatization continues to be a time-and resource-intensive endeavor,attributable mainly to the paucity of a reliable predictive catalyst design strategy.In this study,we systematically compiled a dataset of 847 literaturereported asymmetric phenolic dearomatization by hypervalent iodine(III)catalysts(HVI-CADA dataset),a unique type of catalyst that is gaining increasing attention owing to their ecofriendly features.Leveraging this reaction dataset,we established a machine learning predictive model to predict enantioselectivity.The XGBoost algorithm exhibited the optimal performance,with a root-mean-square error of 0.26(kcal/mol)and an R^(2)of 0.84.This established model can effectively guide the selection of the optimal catalyst and additives in out-of-sample tests.Subsequent independent experiments were conducted to validate the results obtained from the model predictions.We anticipate that our current work will facilitate further design,optimization,and development of novel chiral hypervalent iodine catalysts for new asymmetric phenolic dearomatization reactions.
基金the National Natural Science Foundation of China(Nos.22171154 and 21801144)the Youth Innovative Talents Recruitment and Cultivation Program of Shandong Higher Education,the Natural Science Foundation of Shandong Province(Nos.ZR2020QB114 and ZR2020QB008)+4 种基金Jinan Science&Technology Bureau(No.2021GXRC080)supported by the Foundation(No.ZZ20190312)of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology(Shandong Academy of Sciences)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province,the Open Fund of the Department of Chemistry,Qingdao University of Science and Technology(No.QUSTHX202010)Science and Technology Innovation Development Plan of Yantai(No.2020MSGY114)Yantai“Double Hundred Plan”.
文摘We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.
基金We are grateful to the National Natural Science Foundation of China(Nos.21961037,21861036,22161044 and 22201241)the Program for Tianshan Innovative Research Team of Xinjiang Uygur Autonomous Region(No.2021D14011)+1 种基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Nos.2020D01C077 and 2021D01E10)the Key Program of Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01D06)for support of this research。
文摘Herein,we achieved a green and efficient dearomatization for the synthesis of 2,3-functionalized polycyclic indolines in an electrochemical way.This avoiding of external oxidants and metals approach allowed various nucleophilic sources(Nu¼anilines,TMSN3 and ROH)to perform the products,representing an environmentally benign means.Additionally,the continuous flow electrosynthesis and synthetic transformations also reveal the strong practicality of electrochemistry in organic synthesis.
文摘P450 enzymes-catalyzed aromatic hydroxylation plays an important role in detoxification,biosynthesis,and potential carcinogenic effect of aromatic compounds.Though it has been explored for decades,the actual process of aromatic hydroxylation and mechanism of regioselectivity catalyzed by cytochrome P450 monooxygenases remained ambiguous.Here,we have resolved these issues.With a stable chiral organofluorine probe,and especially with X-ray data of two isolated arene oxides derivatives,we demonstrate that an arene oxide pathway is definitely involved in P450-catalyzed aromatic hydroxylation.By the capture,isolation,identification and reactivity exploration of the arene 1,2-oxide and arene 2,3-oxide intermediates,together with advanced QM calculations,the mechanism of how two intermediates go to the same product has been elucidated.In addition to the model substrate,we also confirmed that an arene oxide intermediate is involved in the P450-catalyzed hydroxylation pathway of a natural product derivative methyl cinnamate,which indicates that this intermediate appears to be universal in P450-catalyzed aromatic hydroxylation.Our work not only provides the most direct evidence for the arene oxide pathway and new insights into the regioselectivity involved in P450-catalyzed aromatic hydroxylation,but also supplies a new synthetic approach to achieve the dearomatization of aromatic compounds.
基金the Qingdao Marine Science and Technology Center(No.2022QNLM030003-2)the Fundamental Research Funds for the Central Universities,Taishan Scholar Program of Shandong Province(No.tsqn202103152)National Natural Science Foundation of China(No.22171251) for financial support。
文摘The first total synthesis of(+)-taberdicatine B and(+)-tabernabovine B has been accomplished in 10steps with 26.9% overall yield and 15 steps with 7.3% overall yield,respectively.The prominent features of this efficient synthetic strategy include the following:(1)(+)-Taberdicatine B and(+)-tabernabovine B were accessed from common advanced intermediates by varying the substituents;(2) A one-pot asymmetric bromocyclization/hydrolysis was explored to assemble HPI skeleton;(3) Dieckmann condensation to form β-keto ester for the assembly of seven-membered ring;(4) An ester reduction/amide semireduction/cyclization sequence was applied to form the cage-like framework.
文摘Catalytic asymmetric dearomatization(CADA)has emerged as a powerful strategy for transforming planar aromatic systems into three-dimensional chiral architectures[1].Notably,the Büchner reaction and arene cyclopropanation excel in constructing complex polycyclic frameworks[2].However,current methods predominantly rely on diazo compounds as carbene precursors(Scheme1a),which pose safety risks and limit functional group compatibility.
文摘An asymmetric fluorinative dearomatization reaction of tryptophol derivatives was developed via chiral anion phase-transfer catalysis. Vari- ous fluorinated furoindolines were obtained in moderate to excellent yields and enantioselectivity in the presence of Selectfluor. The preliminary mecha- nistic studies suggested the existence of an in situ formed tryptophol boronic ester plays a critical role in determining the enantioselectivity. This method features the facile introduction of a fluorine atom in a highly enantioselective manner and construction of two contiguous quaternary stereogenic cen- ters.
