- DABCO-based chiral ionic liquids as recoverable and reusable organocatalyst for asymmetric Diels–Alder reaction
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New DABCO-based chiral ionic liquids were synthesized and evaluated in asymmetric Diels–Alder reaction of cyclopentadiene with α,β-unsaturated aldehydes or 4-phenyl-3-buten-2-one. Chiral ionic liquid of modified MacMillan catalyst having a DABCO cation and hexafluorophosphate anion acts as organocatalyst (5?mol%) for the Diels–Alder reaction of crotonaldehyde and cyclopentadiene producing 98% of the product and 87% ee (endo) in CH3CN/H2O (95/5) at 25°C in 2?h. The scope and limitations of the catalysis were also studied by using cyclopentadiene and α,β-unsaturated aldehydes, and the Diels–Alder products were obtained in 18%–92% yields with 68%–93% ee. The catalyst was recycled and reused up to 6 cycles with a slight drop in ee and conversion of the product.
- Aalam, Mohd Jubair,Deepa,Chaudhary, Pooja,Meena, Dhan Raj,Yadav, Geeta Devi,Singh, Surendra
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supporting information
p. 134 - 146
(2021/11/16)
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- A High Loading and Recyclable Pentaerythritol Supported Imidazolidin-4-one Catalyst for Enantioselective Diels–Alder Reactions
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Abstract: The synthesis of high loading and recyclable pentaerythritol supported imidazolidin-4-one catalyst I and its application in enantioselective Diels–Alder reactions of cyclopentadiene and α,β-unsaturated aldehydes with high performance were descri
- Du, Kaitao,Lu, Cuifen,Chen, Zuxing,Nie, Junqi,Yang, Guichun
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p. 1107 - 1112
(2016/06/01)
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- Pentaerythritol-supported chiral imidazolone and preparation method as well as use thereof
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The invention relates to pentaerythritol-supported chiral imidazolone. The structure of the pentaerythritol-supported chiral imidazolone is shown in the description. Chiral imidazolone is supported on pentaerythritol to obtain a novel pentaerythritol-supp
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Paragraph 0023
(2016/10/08)
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- Improving catalyst activity in secondary amine catalysed transformations
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The effect on catalyst performance of altering substituents at the 2-position of the Macmillan imidazolidinone has been examined. Condensation of l-phenylalanine N-methyl amide with acetophenone derivatives results in a series of imidazolidinones whose sa
- Brazier, John B.,Gibbs, Timothy J. K.,Rowley, Julian H.,Samulis, Leopold,Yau, Sze Chak,Kennedy, Alan R.,Platts, James A.,Tomkinson, Nicholas C. O.
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supporting information
p. 133 - 141
(2015/02/05)
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- New insights into the asymmetric Diels-Alder reaction: The endo- and S-selective retro-Diels-Alder reaction
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The endo- and S-selective retro-Diels-Alder reactions in an imidazolethione-catalyzed asymmetric Diels-Alder reaction were verified and investigated, and account for the low ee values in a CH3CN-H2O catalytic system. This reverse pro
- Li, Na,Liang, Xianrui,Su, Weike
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p. 106234 - 106238
(2015/12/30)
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- Recyclable tetraarylphosphonium supported chiral imidazolidin-4-one organocatalyst for Diels-Alder reactions
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The tetraarylphosphonium supported chiral imidazolidin-4-ones were synthesized and used to catalyze the Diels-Alder reactions of cyclopentadiene and α,β-unsaturated aldehydes. High enantiomeric excesses and good yields were obtained, and catalyst recyclin
- Lin, Zihan,Chen, Zuxing,Yang, Guichun,Lu, Cuifen
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- The development of highly active acyclic chiral hydrazides for asymmetric iminium ion organocatalysis
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Double asymmetric induction has been employed as a tool to optimise pyrazolidinone-derived organocatalysts for the asymmetric iminium ion catalysed Diels-Alder reaction. Mechanistic studies revealed a superior hydrazide catalyst deriving from methanolysis of the chiral pyrazolidinone precursor. This catalyst displays unusually high endo diastereoselectivity and good enantioselectivity with a range of β-arylenals and cyclic dienes at catalyst loadings as low as 1 mol%.
- Gould, Eoin,Lebl, Tomas,Slawin, Alexandra M. Z.,Reid, Mark,Davies, Tony,Smith, Andrew D.
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p. 7877 - 7892
(2013/11/19)
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- Application of recyclable ionic liquid-supported imidazolidinone catalyst in enantioselective Diels-Alder reactions
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The application of ionic liquid-supported imidazolidinone catalyst I in enantioselective Diels-Alder reactions was investigated. The Diels-Alder reactions involving α,β-unsaturated aldehydes and cyclopentadiene proceeded efficiently in the presence of cat
- Shen, Zhi-Liang,Cheong, Hao-Lun,Lai, Yin-Chang,Loo, Wan-Yi,Loh, Teck-Peng
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supporting information
p. 2626 - 2630
(2013/02/22)
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- Micellar-driven substrate selectivity in Cr(salen)Cl catalytic Diels-Alder reaction in water
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A 3.5 increase in catalytic activity was observed in the Cr(III) (salen)Cl 3 catalyzed Diels-Alder reaction between cyclopentadiene 1 with the longer trans-2-decenal 2g compared to the shorter trans-2-butenal 2a dienophile under aqueous micellar conditions, while in chloroform the two substrates react with comparable activities.
- Trentin, Francesco,Scarso, Alessandro,Strukul, Giorgio
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supporting information; experimental part
p. 6978 - 6981
(2012/02/13)
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- A novel hydrazide type organocatalyst for enantioselective Diels-Alder reactions
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The development of a new class of hydrazide type organocatalyst, (4R,5R)-1,3-bis(isopropylamino)-4,5-dihenylimidazolidin-2-one 2a, for enantioselective Diels-Alder reactions between cyclopentadiene and α,β-unsaturated aldehydes are presented. The new organocatalyst 2a promoted the reaction, affording Diels-Alder adducts in good yields with good levels of enantioselectivity.
- Suzuki, Ichiro,Ando, Masafumi,Shimabara, Rumiko,Hirata, Ai,Takeda, Kei
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supporting information; experimental part
p. 3033 - 3040
(2011/05/30)
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- Highly active asymmetric Diels-Alder reactions catalyzed by C2-symmetric bipyrrolidines: catalyst recycling in water medium and insight into the catalytic mode
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A new class of C2-symmetric 3,3′-dialkoxy-2,2′-bipyrrolidines have been designed and synthesized for asymmetric organocatalytic Diels-Alder reactions of α,β-unsaturated aldehydes. The remarkable rate-accelerating effect for the cycloaddition reaction has been observed in aqueous medium. The catalyst 1c·2HClO4 can be recovered and reused several times by simple extraction without significant loss of catalytic activity and stereoselectivity. The catalytic mode has been demonstrated by DFT calculation, NMR, and X-ray crystallographic studies for diiminium intermediate.
- Ma, Yuanhui,Jin, Shangbin,Kan, Yuhe,Zhang, Yong Jian,Zhang, Wanbin
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experimental part
p. 3849 - 3854
(2010/07/02)
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- Immobilization of macMillan imidazolidinone as mac-SILC and its catalytic performance on sustainable enantioselective dielsAlder cycloaddition
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MacMillan's imidazolidinone catalyst was immobilized as a supported ionic liquid catalyst (Mac-SILC) in the pores of silica gel with the aid of an ionic liquid - 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The heterogenized organocatalyst was utilized for the enantioselective Diels-Alder reaction of cyclopentadiene and cinnamaldehyde, recovered by simple filtration and subsequent evacuation, and repeatedly used up to six times in 81% average chemical yield, 87% ee for endo- and 80% ee for exo-products. The Mac-SILC was effective for a variety of substrates.
- Hagiwara, Hisahiro,Kuroda, Toshihiro,Hoshi, Takashi,Suzuki, Toshio
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experimental part
p. 909 - 916
(2010/07/05)
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- Novel tetrahydroisoquinoline based organocatalysts for asymmetric Diels-Alder reactions: Insight into the catalytic mode using ROESY NMR and DFT studies
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For the first time an organocatalyst bearing a secondary nitrogen within a cyclohexane ring has been evaluated in the asymmetric Diels-Alder reaction. This organocatalyst is also the first of its kind based on a (1R,3S)-6,7-dimethoxy- 1-phenyl-1,2,3,4-tetrahydroisoquinoline backbone. These catalysts were tested over a range of dienes and dienophiles and displayed promising chemical conversions of up to 100% with up to 64% ee with triflic acid as the cocatalyst. Density functional theory computational studies and 2D NMR spectroscopy were used to determine the structure of the intermediate iminium ion formed between the most efficient catalyst and cinnamaldehyde. The reaction profile for each of the four possibilities in this reaction were calculated and it was found that the iminium intermediate leading to the major product is higher in energy but kinetically preferred. The activation energies of all possible reaction paths were calculated and the results correlated with the observed products. These experiments revealed that the presence of both (E)- and (Z)-isomers of the cinnamaldehyde were contributing factors for the low enantioselectivity of the reaction products.
- Naicker, Tricia,Petzold, Katja,Singh, Thishana,Arvidsson, Per I.,Kruger, Hendrik G.,Maguire, Glenn E.M.,Govender, Thavendran
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experimental part
p. 2859 - 2867
(2011/03/19)
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- Structural effects in pyrazolidinone-mediated organocatalytic Diels-Alder reactions
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A range of pyrazolidin-3-ones have been prepared and their activity as catalysts for iminium-ion promoted Diels-Alder reactions evaluated. Systematic variation of the C(5)- and N(2)-substituents indicates that the incorporation of an electron withdrawing
- Gould, Eoin,Lebl, Tomas,Slawin, Alexandra M.Z.,Reid, Mark,Smith, Andrew D.
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experimental part
p. 8992 - 9008
(2011/01/04)
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- Synthesis and application of novel imidazole and 1H-tetrazolic acid containing catalysts in enantioselective organocatalyzed Diels-Alder reactions
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Herein we report studies on the organocatalytic Diels-Alder reaction using a variety of catalysts capable of activating α,β-unsaturated carbonyl compounds for reactions with dienes. The structurally attractive catalysts 4 and 14 were utilized in the enant
- Hartikka, Antti,Hojabri, Leila,Bose, Partha Pratim,Arvidsson, Per I.
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experimental part
p. 1871 - 1876
(2010/02/27)
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- Camphor-derived sulfonylhydrazines: catalysts for Diels-Alder cycloadditions
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Camphor-derived sulfonylhydrazines proved to be very active for organocatalyzed Diels-Alder cycloadditions with cyclopentadiene. Good chemical yields and enantiomeric excesses up to 89% and 88% are obtained for endo/exo adducts.
- Langlois, Yves,Petit, Alain,Rémy, Pauline,Scherrmann, Marie-Christine,Kouklovsky, Cyrille
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scheme or table
p. 5576 - 5579
(2009/04/11)
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- Camphor sulfonyl hydrazines (CaSH) as organocatalysts in enantioselective Diels-Alder reactions
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(Chemical Equation Presented) Cyclic sulfonyl hydrazine was demonstrated for the first time as a new functionality for organocatalysis. A series of six-membered cyclic hydrazines derived from camphor sulfonic acid were synthesized. With trichloroacetic acid as cocatalyst, they are efficient organocatalysts for enantioselective Diels-Alder reactions with good chemical yields and up to 96% ee. The reactions took place in brine at 0 °C to room temperature.
- He, Hao,Pei, Bao-Jian,Chou, Ho-Hsuan,Tian, Tian,Chan, Wing-Hong,Lee, Albert W. M.
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supporting information; experimental part
p. 2421 - 2424
(2009/05/26)
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- A recyclable fluorous organocatalyst for Diels-Alder reactions
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Chiral fluorous imidazolidinone catalyst 2 provides consistently high enantioselectivities in Diels-Alder reactions of dienes and α,β-unsaturated aldehydes. The catalyst can be readily separated from the reaction products by fluorous solid-phase extractio
- Chu, Qianli,Zhang, Wei,Curran, Dennis P.
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p. 9287 - 9290
(2007/10/03)
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- Organocatalysis using protonated 1,2-diamino-1,2-diphenylethane for asymmetric Diels-Alder reaction
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Bisammonium salts of mono-N-alkylated chiral 1,2-diamino-1,2-diphenylethane (DPEN) were employed in the catalytic and asymmetric Diels-Alder reaction between cyclopentadiene and crotonaldehyde. The N-3-pentyl diamine·2HCl catalyst shows high endo/exo selectivity and endo-enantioselectivity for the cycloaddition, and this organocatalysis is the first example of the use of a chiral 1,2-diamine to generate an imine intermediate which is activated by an internal ammonium Br?nsted acid for the cycloaddition in a wet solvent.
- Kim, Kyoung Hoon,Lee, Seil,Lee, Dae-Woong,Ko, Dong-Hyun,Ha, Deok-Chan
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p. 5991 - 5994
(2007/10/03)
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- Aqueous enantioselective organocatalytic Diels-Alder reactions employing hydrazide catalysts. A new scaffold for organic acceleration
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(Chemical Equation Presented) Cyclic hydrazides function as asymmetric organocatalysts in aqueous Diels-Alder reactions. The hydrazide is employed as the catalytic machinery in a compact camphor-derived framework that imparts facial selectivity to the cyc
- Lemay, Mathieu,Ogilvie, William W.
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p. 4141 - 4144
(2007/10/03)
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- Chemical transformation of substrates using nonmetallic, organic catalyst compositions
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A method is provided for catalytically transforming a functional group within a first reactant by reaction with a second reactant in the presence of a nonmetallic, organic catalyst composition composed of a heteroatom-containing activator and an acid, or a salt of a heteroatom-containing activator and an acid. Exemplary first reactants are α,β-unsaturated carbonyl compounds such as α,β-unsaturated ketones and α,β-unsaturated aldehydes. The heteroatom of the activator is a Group 15 or Group 16 element such as nitrogen, oxygen, sulfur or phosphorus, and exemplary heteroatom-containing activators are amines. Chiral heteroatom-containing activators can be used to catalyze enantioselective reactions, such that a chiral product is obtained from a chiral or achiral starting material in enantiomerically pure form.
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- Aqueous catalysis: Methylrhenium trioxide (MTO) as a homogeneous catalyst for the Diels-Alder reaction
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The title compound proves to be an effective and efficient catalyst for the Diels-Alder reaction when the dienophile is an α,β-unsaturated ketone or aldehyde. It is especially effective in water. Equal amounts of any such dienophile and any of six representative dienes (isoprene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, cyclopentadiene, 1,2,3,4,5-pentamethylcyclopentadiene, and 1,3-cyclohexadiene) were used, along with 1% MTO. The reactions gave usually > 90% isolated yield of the cycloaddition product except for the larger dienophiles. Nearly exclusively, there was formed one product isomer, the same one that usually predominates. The reactions were often run in chloroform (mostly) and in other organic solvents. A select number were carried out in water, where the reactions gave a greater product yield in a considerably shorter time. Water, itself, is known to enhance the rates of Diels-Alder reactions, but MTO exerts an additional accelerating effect. Kinetics studies were carried out to show that the rate is proportional to the catalyst concentration. The products do not inhibit the reaction. The desirability of MTO as a Diels-Alder catalyst stems from a combination of favorable properties: the inertness to air/oxygen, the tolerance for many substrates, the use of an aqueous medium, and the absence of product inhibition. The initial step appears to be the (weak) coordination of the carbonyl oxygen to the electropositive rhenium center. Steric crowding around rhenium inhibits reactions of the larger dienophiles.
- Zhu, Zuolin,Espenson, James H.
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p. 3507 - 3512
(2007/10/03)
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