2, 3, 3a, 4, 5, 9b-hexahydro-8-(N-methylsulfamylmethyl)-4-phenylfuro[3, 2-c]quinoline was obtained when the alkylation of compound 1 was carried out with THF as solvent. The structure of the product was determined and...2, 3, 3a, 4, 5, 9b-hexahydro-8-(N-methylsulfamylmethyl)-4-phenylfuro[3, 2-c]quinoline was obtained when the alkylation of compound 1 was carried out with THF as solvent. The structure of the product was determined and the mechanism of the reaction was studied and proved by the imitation reaction.展开更多
Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the cor...Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields.展开更多
Extensive experimental studies have been performed on the Diels-Alder(DA)reactions in ionic liquids(ILs),which demonstrate that the IL environment can significantly influence the reaction rates and selectivity.However...Extensive experimental studies have been performed on the Diels-Alder(DA)reactions in ionic liquids(ILs),which demonstrate that the IL environment can significantly influence the reaction rates and selectivity.However,the underlying microscopic mechanism remains ambiguous.In this work,the multiscale reaction density functional theory is applied to explore the effect of 1-butyl-3-methylimidazolium hexafluorophosphate([BMIM][PF_(6)])solvent on the reaction of cyclopentadiene(CP)with acrolein,methyl acrylate,or acrylonitrile.By analyzing the free energy landscape during the reaction,it is found that the polarization effect has a relatively small influence,while the solvation effect makes both the activation free energy and reaction free energy decrease.In addition,the rearrangement of local solvent structure shows that the cation spatial distribution responds more evidently to the reaction than the anion,and this indicates that the cation plays a dominant role in the solvation effect and so as to affect the reaction rates and selectivity of the DA reactions.展开更多
The mechanism, catalytic effect and substituent effect of the hetero-Diels-Alder reactions between phosphonodithioformate and butadienes have been investigated theoretically using density functional theory at the B3LY...The mechanism, catalytic effect and substituent effect of the hetero-Diels-Alder reactions between phosphonodithioformate and butadienes have been investigated theoretically using density functional theory at the B3LYP/6-31G（d） level. The results show that all of these reactions proceed in a concerted but asynchronous way. In some reactions the formation of C-S bond is prior to that of C-C and opposite result is found in other reactions. The BF3 catalyst and trimethylsilyloxy group may lower the activation barriers by changing the energies of FMOs for reactant molecules. With the BF3-catalyzed reactions, the complete regioselectivity observed experimentally has well been reproduced by theoretical calculation and these results originate probably from blue-shifting C-H...F hydrogen bond interaction in some transition states.展开更多
Novel Schiff bases of H4＇-NOBIN 5a and 5b were synthesized by condensation of 3 with aldehydes. Compound 5b was structurally characterized by single-crystal X-ray diffraction. The asymmetric hetero-Diels-Alder reacti...Novel Schiff bases of H4＇-NOBIN 5a and 5b were synthesized by condensation of 3 with aldehydes. Compound 5b was structurally characterized by single-crystal X-ray diffraction. The asymmetric hetero-Diels-Alder reactions were carried out with high yields and good enantioselectivities in the presence of Ti-（S）-5a complex as catalyst. Crystallographic data for 5b： C27H22BrNO, Mr = 456.37, triclinic, space group P1 with a = 9.1618（2）, b = 10.3836（2）, c = 12.7718（2） А,α=105.4860（10）,β= 94.6360（10）, γ= 108.4610（10）°, V= 1092.32（4）А^3, Z=2, Dc= 1.388 g/cm^3, μ= 1.900 mm^-1, F（000） = 468, R = 0.0476 and wR = 0.1248 for 3092 observed reflections （I〉 2σ（I））.展开更多
The mechanism, catalytic effect and solvent effect of the hetero-Diels-Alder reactions between 3-pyddinedithioesters and 1-phenylsulfanylbutadiene have been studied theoretically using density functional theory （DFT...The mechanism, catalytic effect and solvent effect of the hetero-Diels-Alder reactions between 3-pyddinedithioesters and 1-phenylsulfanylbutadiene have been studied theoretically using density functional theory （DFT） at the B3LYP/6-31G（d） level. The results show that all of these reactions proceed in a concerted but asynchronous way. In some reactions the formation of C-S bond is prior to that of C-C bond and the opposite results are found in other reactions. The BF3 catalyst may lower the activation barriers by changing the energies of LUMO for 3-pyridinedithioester. THF solvent has trivial influence on the potential energy surface of these reactions. With the BF3-catalyzed reactions, regioselectivity and stereoselectivity observed experimentally were predicted correctly by calculations and these results originate probably from C-H…F interaction in two transition states.展开更多
The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than i...The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than in the conventional organic solvent. Furthermore, in the Diels-Alder reactions of 2- and 2,5-alkylfurans with N-alkylma- leimide, the reactivity increases by extending the alkyl chain length of N-alkylmaleimide. In addition, it was demon- strated that endo-selectivity increases when 2,5-disubstituted furans are used. These results will be explained by comparing the stability of the Diels-Alder adduct with that of the products obtained from the reactions of 2-substituted furans and 2,5-disubstituted furans.展开更多
Four novel bisoxazoline ligands 8a-d were synthesized from （S）-amino alcohols and could be formed effective catalysts （up to 77% ee for endo isomer） with Cu（OTf）2 for enantioselective Diels-Alder addition. The f...Four novel bisoxazoline ligands 8a-d were synthesized from （S）-amino alcohols and could be formed effective catalysts （up to 77% ee for endo isomer） with Cu（OTf）2 for enantioselective Diels-Alder addition. The facility of the reaction was dependent on the nature of the substituent R in the bisoxazoline ligand.展开更多
Diels-Alder reaction of hedychenone 1 and maleic anhydride 2 gave several products 4 similar to 7, whose structures were identified by spectral methods. Effect of temperature on the reaction was disscussed.
Aluminum chloride induced Diels-Alder reactions of 3-carboethoxy- and 3-carbonitrile-2-cyclohexen-1-one with cyclopentadiene, isoprene and (E)-piperylene were described. Thestereochemistry of the adducts were confirme...Aluminum chloride induced Diels-Alder reactions of 3-carboethoxy- and 3-carbonitrile-2-cyclohexen-1-one with cyclopentadiene, isoprene and (E)-piperylene were described. Thestereochemistry of the adducts were confirmed by 2D-NMR spectroscopy and isomerizationreactions.展开更多
The seleno substituted aromatic compounds were prepared via the Diels-Alder reaction of seleno substituted 3-sulfolenes with dimethyl acetylenedicarboxylate followed by DDQ dehydrogenation.
Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent i...Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed Absolute configuration of the cycloadducts was conformed. Dramatic reversal of selectivity is observed.展开更多
Symmetric, diesters of cis- or trans- bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylate were prepared by aqueous Diels-Alder reaction of cyclopentadiene with symmetric diester of fumarate or maleate.
The yield and stereoselectivity of the Diels-Alder reactions between furan(or 2-methylfuran)and different dienophiles are markedly enhanced by the catalysis of anhydrous YbCl_3.
文摘2, 3, 3a, 4, 5, 9b-hexahydro-8-(N-methylsulfamylmethyl)-4-phenylfuro[3, 2-c]quinoline was obtained when the alkylation of compound 1 was carried out with THF as solvent. The structure of the product was determined and the mechanism of the reaction was studied and proved by the imitation reaction.
文摘Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields.
基金supported by the National Natural Science Foundation of China(22168002,22108070,21878078)the Natural Science Foundation of Guangxi Province(2020GXNSFAA159119)+2 种基金the Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021Z012)the Open Fund of the State Key Laboratory of Molecular Reaction Dynamics in DICP(SKLMRD-K202106)the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)。
文摘Extensive experimental studies have been performed on the Diels-Alder(DA)reactions in ionic liquids(ILs),which demonstrate that the IL environment can significantly influence the reaction rates and selectivity.However,the underlying microscopic mechanism remains ambiguous.In this work,the multiscale reaction density functional theory is applied to explore the effect of 1-butyl-3-methylimidazolium hexafluorophosphate([BMIM][PF_(6)])solvent on the reaction of cyclopentadiene(CP)with acrolein,methyl acrylate,or acrylonitrile.By analyzing the free energy landscape during the reaction,it is found that the polarization effect has a relatively small influence,while the solvation effect makes both the activation free energy and reaction free energy decrease.In addition,the rearrangement of local solvent structure shows that the cation spatial distribution responds more evidently to the reaction than the anion,and this indicates that the cation plays a dominant role in the solvation effect and so as to affect the reaction rates and selectivity of the DA reactions.
文摘The mechanism, catalytic effect and substituent effect of the hetero-Diels-Alder reactions between phosphonodithioformate and butadienes have been investigated theoretically using density functional theory at the B3LYP/6-31G（d） level. The results show that all of these reactions proceed in a concerted but asynchronous way. In some reactions the formation of C-S bond is prior to that of C-C and opposite result is found in other reactions. The BF3 catalyst and trimethylsilyloxy group may lower the activation barriers by changing the energies of FMOs for reactant molecules. With the BF3-catalyzed reactions, the complete regioselectivity observed experimentally has well been reproduced by theoretical calculation and these results originate probably from blue-shifting C-H...F hydrogen bond interaction in some transition states.
基金supported by the Natural Science Foundation of Zhejiang Province (No. Y405013)
文摘Novel Schiff bases of H4＇-NOBIN 5a and 5b were synthesized by condensation of 3 with aldehydes. Compound 5b was structurally characterized by single-crystal X-ray diffraction. The asymmetric hetero-Diels-Alder reactions were carried out with high yields and good enantioselectivities in the presence of Ti-（S）-5a complex as catalyst. Crystallographic data for 5b： C27H22BrNO, Mr = 456.37, triclinic, space group P1 with a = 9.1618（2）, b = 10.3836（2）, c = 12.7718（2） А,α=105.4860（10）,β= 94.6360（10）, γ= 108.4610（10）°, V= 1092.32（4）А^3, Z=2, Dc= 1.388 g/cm^3, μ= 1.900 mm^-1, F（000） = 468, R = 0.0476 and wR = 0.1248 for 3092 observed reflections （I〉 2σ（I））.
文摘The mechanism, catalytic effect and solvent effect of the hetero-Diels-Alder reactions between 3-pyddinedithioesters and 1-phenylsulfanylbutadiene have been studied theoretically using density functional theory （DFT） at the B3LYP/6-31G（d） level. The results show that all of these reactions proceed in a concerted but asynchronous way. In some reactions the formation of C-S bond is prior to that of C-C bond and the opposite results are found in other reactions. The BF3 catalyst may lower the activation barriers by changing the energies of LUMO for 3-pyridinedithioester. THF solvent has trivial influence on the potential energy surface of these reactions. With the BF3-catalyzed reactions, regioselectivity and stereoselectivity observed experimentally were predicted correctly by calculations and these results originate probably from C-H…F interaction in two transition states.
文摘The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than in the conventional organic solvent. Furthermore, in the Diels-Alder reactions of 2- and 2,5-alkylfurans with N-alkylma- leimide, the reactivity increases by extending the alkyl chain length of N-alkylmaleimide. In addition, it was demon- strated that endo-selectivity increases when 2,5-disubstituted furans are used. These results will be explained by comparing the stability of the Diels-Alder adduct with that of the products obtained from the reactions of 2-substituted furans and 2,5-disubstituted furans.
基金Finacial support by the National Natural Science Foundation of China(No.2047211)the Science Foundation of China Agricultural University(No.2005058)is gratefully acknowledged.
文摘Four novel bisoxazoline ligands 8a-d were synthesized from （S）-amino alcohols and could be formed effective catalysts （up to 77% ee for endo isomer） with Cu（OTf）2 for enantioselective Diels-Alder addition. The facility of the reaction was dependent on the nature of the substituent R in the bisoxazoline ligand.
文摘Diels-Alder reaction of hedychenone 1 and maleic anhydride 2 gave several products 4 similar to 7, whose structures were identified by spectral methods. Effect of temperature on the reaction was disscussed.
文摘Aluminum chloride induced Diels-Alder reactions of 3-carboethoxy- and 3-carbonitrile-2-cyclohexen-1-one with cyclopentadiene, isoprene and (E)-piperylene were described. Thestereochemistry of the adducts were confirmed by 2D-NMR spectroscopy and isomerizationreactions.
文摘The seleno substituted aromatic compounds were prepared via the Diels-Alder reaction of seleno substituted 3-sulfolenes with dimethyl acetylenedicarboxylate followed by DDQ dehydrogenation.
文摘Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed Absolute configuration of the cycloadducts was conformed. Dramatic reversal of selectivity is observed.
文摘Symmetric, diesters of cis- or trans- bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylate were prepared by aqueous Diels-Alder reaction of cyclopentadiene with symmetric diester of fumarate or maleate.
文摘The yield and stereoselectivity of the Diels-Alder reactions between furan(or 2-methylfuran)and different dienophiles are markedly enhanced by the catalysis of anhydrous YbCl_3.
