- Silica gel-mediated catalyst-free and solvent-free Michael addition of 1,3-dicarbonyl compounds to highly toxic methyl vinyl ketone without volatilization
-
Silica gel-mediated Michael addition of 1,3-dicarbonyl compounds to methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) was carried out to give the corresponding adducts in quite excellent yields. The reactions could be carried out without any catalysts and solvents. In addition, highly toxic MVK and EVK could be employed without significant volatilization. Silica gel could be recycled five times without the decrease of the yields.
- Tanemura, Kiyoshi,Rohand, Taoufik
-
supporting information
(2020/06/28)
-
- Michael addition of cyclic β-oxo ester and α-methyl cyano ester substrates with activated olefins by iron complexes of benzimidazole derived N-heterocyclic carbene ligands
-
Michael addition reactions of cyclic β-oxo ester and α-methyl cyano ester substrates with acceptor activated olefins were catalyzed by iron N?heterocyclic carbene (NHC) complexes of the type, {Cp[1-benzyl-3-alkyl-benzimidazol-2-ylidene]Fe(CO)2}
- Prakasham,Gangwar, Manoj Kumar,Ghosh, Prasenjit
-
supporting information
p. 106 - 116
(2018/02/15)
-
- Michael addition catalyzed by difluorotris(pentafluoroethyl)phosphorane
-
Difluorotris(pentafluoroethyl)phosphorane, (C2F5)3PF2, was found to be an active catalyst for the Michael addition reaction of 1,3-β-diketones or β-ketoesters (Michael donors) and linear or cyclic unsaturated ketones (Michael acceptors). The reaction proceeds under mild conditions with low catalyst loading and results in the formation of the Michael addition products in moderate to high yields. The developed protocol does not require the use of a base for the in situ generation of a carbanion (Michael donor).
- Bittner, Bozena,Koppe, Karsten,Frank, Walter,Ignat'Ev, Nikolai
-
supporting information
p. 22 - 27
(2015/12/30)
-
- Air- and water-tolerant rare earth guanidinium BINOLate complexes as practical precatalysts in multifunctional asymmetric catalysis
-
Shibasaki's REMB catalysts (REMB; RE = Sc, Y, La-Lu; M = Li, Na, K; B = 1,1′-bi-2-naphtholate; RE/M/B = 1/3/3) are among the most enantioselective asymmetric catalysts across a broad range of mechanistically diverse reactions. However, their widespread us
- Robinson, Jerome R.,Fan, Xinyuan,Yadav, Jagjit,Carroll, Patrick J.,Wooten, Alfred J.,Pericàs, Miquel A.,Schelter, Eric J.,Walsh, Patrick J.
-
supporting information
p. 8034 - 8041
(2014/06/23)
-
- PRECATALYST FOR SHIBASAKI'S RARE EARTH METAL BINOLATE CATALYSTS
-
Disclosed herein are schemes for the synthesis of novel hydrogen-bonded rare earth- BINOLate precatalyst complexes, the precatalysts, per se, and their application for the generation of anhydrous REMB catalysts by cation-exchange from metal halides.
- -
-
Page/Page column 12-16; 29
(2015/01/07)
-
- Iron catalyzed Michael addition: Chloroferrate ionic liquids as efficient catalysts under microwave conditions
-
The iron containing ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate ([C4mim]Cl/FeCl3; χ = 0.5) proved to be an efficient catalyst for the solvent-free metal catalyzed Michael addition of ?-keto esters and enones. Due to the ionic st
- Vasiloiu, Maria,Gaertner, Peter,Bica, Katharina
-
p. 1614 - 1619
(2012/11/07)
-
- Phosphine-boronates: Efficient bifunctional organocatalysts for Michael addition
-
Phosphine-boronates R2P(o-C6H4) B(OR′)2 have been evaluated as bifunctional organocatalysts for the Michael addition of malonate pronucleophiles to methylvinylketone. The presence of the Lewis acidic boron center adjacent to phosphorus significantly improves catalytic performance. Isolation and complete characterization of a key intermediate, namely a β-phosphonium enolate, substantiate the role of the Lewis acidic moiety in the catalytic process.
- Basle, Olivier,Porcel, Susana,Ladeira, Sonia,Bouhadir, Ghenwa,Bourissou, Didier
-
supporting information; experimental part
p. 4495 - 4497
(2012/05/31)
-
- Structure and catalytic activity of organopalladium(II) complexes based on 4,5-dihydro-1H-imidazol-5-one derivatives
-
The paper describes preparation of a chiral bidentate ligand - 2-(2-bromophenyl)-4,5-dihydro-1H-imidazol-5-one, and a tridentate ligand - 2-bromo-1,3-bis(4,5-dihydro-1H-imidazol-5-on-2-yl)benzene, whose oxidative addition reaction with Pd(0) giving neutra
- Drabina, Pavel,Bro?, B?etislav,Padělková, Zdeňka,Sedlák, Milo?
-
experimental part
p. 971 - 981
(2011/03/22)
-
- Asymmetric lewis acid catalysis in water: α-amino acids as effective ligands in aqueous biphasic catalytic michael additions
-
This article explores the potential of native α-amino acids as chiral ligands in aqueous asymmetric Lewis acid catalysis, employing the C-C bond forming Michael addition as a model reaction. Some insights are provided regarding the details of Yb(OTf)
- Aplander, Karolina,Ding, Rui,Krasavin, Mikhail,Lindstroem, V. Marcus,Wennerberg, Johan
-
experimental part
p. 810 - 821
(2009/07/05)
-
- Nickel complexes of nio-functionalized n-Heterocyclic carbenes as precatalysts for michael reactions in air at room temperature under the much preferred base-Free conditions
-
A series of several new nickel precatalysts supported over N/O-functionalized N-heterocyclic carbenes (NHC) for the Michael reactions of B-dicarbonyl, B-keto ester, B-diester, and a-cyano ester compounds with a,B-unsaturated carbonyl compounds in air at ambient temperature under the much preferred base-free conditions are reported. Specifically, the nickel complexes, [1-(R1-aminocarbonylmethyl)-3-R2-imid-azol-2-ylidene]2Ni [R1 =2-C6H4(OMe); R2 = Me (1b), iPr (2b), CH2Ph (3b) and R1 = 2-CH2C4H3O; R2 =Me (4b), CH2Ph (5b)] carried out the highly convenient base-free Michael addition of the activated C-H compounds across a,B-unsaturated car- bonyl compounds in air at room temperature. The complexes 1b-5b were synthesized by the direct reaction of the respective imidazolium chloride salt with NiCl2-6H2Oin CH3CN in the presence of K2CO3 as a base. The exceptional stability of 1b-5b has been attributed to the deeply buried nickel-NHC CT-bonding molecular orbitals as evidenced from the density functional theory (DFT) studies. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009.
- Ray, Sriparna,Shaikh, Mobin M.,Ghosh, Prasenjit
-
experimental part
p. 1932 - 1941
(2009/10/30)
-
- α-amino acid induced rate acceleration in aqueous biphasic Lewis acid catalyzed Michael addition reactions
-
It's as easy as ABC: α-Amino acids may become very important tools in the development of economical and environmentally friendly aqueous biphasic catalysis. Alanine accelerated an Yb(OTf)3-catalyzed Michael addition by a factor of 138. The solubilizing and stabilizing properties of alanine allowed the metal catalyst to be "heterogenized" in the aqueous phase and recycled multiple times without appreciable loss of activity.
- Aplander, Karolina,Ding, Rui,Lindstrom, U. Marcus,Wennerberg, Johan,Schultz, Sara
-
p. 4543 - 4546
(2008/09/17)
-
- Quadrapure cartridges for removal of trace metal from reaction mixtures in flow
-
Packed cartridges of QuadraPure metal scavengers have been used to reduce levels of metal contaminants in a single-pass flow method. Five examples are given of simplified purification of metal-mediated reactions. QuadraPure cartridges demonstrated excellent clean-up in comparison with traditional methods for metal removal.
- Hinchcliffe,Hughes,Pears,Pitts
-
p. 477 - 481
(2012/12/31)
-
- Enantiodivergent synthesis of 3-amino-4,4-dimethyl-1-phenylpyrrolidin-2-one and derivatives: amino analogues of pantolactone
-
An enantiodivergent preparation of (+)-(R)- and (-)-(S)-3-amino-4,4-dimethyl-1-phenylpyrrolidin-2-one, (R)- and (S)-9, and several derivatives, from 4,4-dimethyl-1-phenylpyrrolidin-2,3-dione, 4, and (R)- or (S)-1-phenylethylamine, (R)- or (S)-5, as the chirality transfer agents, is described. Amine (S)-9 has also been used as a chiral auxiliary in a diastereoselective Michael reaction.
- Camps, Pelayo,Munoz-Torrero, Diego,Rull, Jordi,Font-Bardia, Merce,Solans, Xavier
-
p. 2947 - 2958
(2008/09/17)
-
- Expanding the scope of Lewis acid catalysis in water: Remarkable ligand acceleration of aqueous Ytterbium triflate catalyzed Michael addition reactions
-
Significant rate acceleration of metal-catalyzed Michael addition reactions in water was observed upon addition of small, dibasic ligands. Ytterbium triflate and TMEDA was the most effective combination leading to a nearly 20-fold faster reaction than in the absence of ligand.
- Ding, Rui,Katebzadeh, Kambiz,Roman, Lisa,Bergquist, Karl-Erik,Lindstroem, Ulf M.
-
p. 352 - 355
(2007/10/03)
-
- Creation of monomeric La complexes on apatite surfaces and their application as heterogeneous catalysts for Michael reactions
-
Using a cation-exchange method, an equimolar substitution of La 3+ for Ca2+ occurred by the treatment of stoichiometric hydroxyapatite (HAP: Ca10(PO4)6(OH) 2) with an aqueous solution of La(OTf)3, affording a monomeric hydroxyapatite-bound La complex (LaHAP). Physicochemical characterization by means of XRD, XPS, IR, and La K-edge XAFS analyses proved that a monomeric La3+ phosphate complex was generated on its surface. Such monomeric La3+ species function as an efficient heterogeneous catalyst for the Michael reaction of 1,3-dicarbonyls with enones under aqueous or solvent-free conditions. The work-up procedure is straightforward and the spent catalyst could be recycled without any loss of the catalytic activity. Further application to an asymmetric version was also investigated using various apatite catalysts modified with chiral organic ligands. Enantioselectivity was found to depend on the chiral ligand, solvent, and rare earth metal triflate precursor (RE(OTf)3) for the reaction of methyl 1-oxoindan-2- carboxylate with methyl vinyl ketone. Under optimized reaction conditions, a monomeric fluoroapatite-bound La complex catalyst modified with (R,R)-tartaric acid (TA-LaFAP) provided the Michael adduct quantitatively in up to 60% ee. the Royal Society of Chemistry the Centre National de la Recherche Scientifique 2006.
- Mori, Kohsuke,Oshiba, Michitaka,Hara, Takayoshi,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
-
-
- Highly efficient C-C bond-forming reactions in aqueous media catalyzed by monomeric vanadate species in an apatite framework
-
A calcium vanadate apatite (VAp), in which PO43- of hydroxyapatite (HAP), Ca10(PO4)6(OH) 2, is completely substituted by VO43- in the apatite framework, was synthesized. Physicochemical analysis of the VAp reveals the presence of isolated VO4 tetrahedron units with a pentavalent oxidation state. The VAp acts as a high-performance heterogeneous base catalyst for various carbon-carbon bond-forming reactions such as Michael and aldol reactions in aqueous media and the H-D exchange reactions using deuterium oxide. For example, a 200-mmol-scale Michael reaction under triphasic conditions proceeded rapidly, with an extremely high turnover number of up to 260 400 and an excellent turnover frequency of 48 s-1. No vanadium leaching was detected during the above reactions, and the catalyst was readily recycled with no loss of activity.
- Hara, Takayoshi,Kanai, Satoko,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
-
p. 7455 - 7462
(2007/10/03)
-
- Michael reaction of β-ketoesters with vinyl ketones by iron(III)-exchanged fluorotetrasilicic mica: Catalytic and spectroscopic studies
-
Michael reaction of β-ketoesters with vinylketones at room temperature under solvent-free condition is investigated with various Fe3+ catalysts, including FeCl3 ·6H2O supported on various supports (Fe-mica, Fe-mont, Fe-SiO
- Shimizu, Ken-Ichi,Miyagi, Masato,Kan-No, Toshiki,Hatamachi, Tsuyoshi,Kodama, Tatsuya,Kitayama, Yoshie
-
p. 470 - 479
(2007/10/03)
-
- Neutral Lewis bases as activators of molecular sieves in the conjugate addition of 1,3-dicarbonyl compounds
-
The catalytic properties of 3 A molecular sieves in the promotion of Michael addition of 1,3-dicarbonyl compounds are significantly improved by activation with several neutral Lewis bases. Comparable efficiency can be observed under solvent-free condition
- Villano, Rosaria,Scettri, Arrigo
-
p. 757 - 760
(2007/10/03)
-
- ZrCl4-catalyzed Michael reaction of 1,3-dicarbonyls and enones under solvent-free conditions
-
ZrCl4 has been found to catalyze the conjugate addition of 1,3-dicarbonyl compounds with enones. The reaction does not require any solvent and proceeds smoothly at room temperature leading to the corresponding adduct in good yields.
- Smitha,Patnaik, Sujatha,Reddy, Ch. Sanjeeva
-
p. 711 - 713
(2007/10/03)
-
- Copper(II) triflate immobilized in [bmim]BF4 ionic liquid: An efficient reaction medium for Michael addition of β-ketoesters to acceptor-activated alkenes
-
1,3-Dicarbonyl compounds undergo smooth conjugate addition to α,β-unsaturated ketones in the presence of 10 mol % copper(II) triflate immobilized in air and moisture stable [bmim]BF4 ionic liquid under extremely mild conditions to afford the co
- Yadav,Reddy,Baishya, Gakul,Venkat Narsaiah
-
p. 102 - 103
(2007/10/03)
-
- Michael reaction of 1,3-dicarbonyls with enones catalyzed by a hydroxyapatite-bound La complex
-
A hydroxyapatite-bound La complex, which functioned as an efficient heterogeneous catalyst for the Michael reaction of 1,3-dicarbonyls with enones under aqueous or solvent-free conditions, was prepared using a cation-exchange method. Further application to an asymmetric version by a fluoroapatite-bound La complex catalyst modified with (R,R)-tartaric acid is also described.
- Mori, Kohsuke,Oshiba, Michitaka,Hara, Takayoshi,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
-
p. 4283 - 4286
(2007/10/03)
-
- Monomeric metal aqua complexes in the interlayer space of montmorillonites as strong Lewis acid catalysts for heterogeneous carbon-carbon bond-forming reactions
-
Montmorillonite-enwrapped copper and scandium catalysts (Cu2-- and Sc3+-monts) were easily prepared by treating Na--mont with the aqueous solution of the copper nitrate and scandium triflate, respectively. The resulting Cu2+- and Sc3+-monts showed outstanding catalytic activities for a variety of carbon-carbon bond-forming reactions, such as the Michael reaction, the Sakurai-Hosomi allylation, and the Diels-Alder reaction, under solvent-free or aqueous conditions. The remarkable activity of the mont catalysts is attributable to the negatively charged silicate layers that are capable of stabilizing metal cations. Furthermore, these catalysts were reusable without any appreciable loss in activity and selectivity. The Cu2+-mont-catalyzed Michael reaction proceeds via a ternary complex in which both the 1,3-dicarbonyl compound and the enone are coordinated to a Lewis acid Cu2+ center.
- Kawabata, Tomonori,Kato, Masaki,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
-
p. 288 - 297
(2007/10/03)
-
- P-BEMP: A new efficient and commercially available user-friendly and recyclable heterogeneous organocatalyst for the Michael addition of 1,3-dicarbonyl compounds
-
Michael addition of 1,3-dicarbonyls with various Michael acceptors has been found to be catalyzed by commercially available, user-friendly and recyclable N-phenyl-tris(dimethylamino)iminophosphorane immobilized on polystyrene resin (P-BEMP). The reaction
- Bensa, David,Constantieux, Thierry,Rodriguez, Jean
-
p. 923 - 927
(2007/10/03)
-
- Utilization of nonionic bases in water as a highly efficient organocatalytic system for Michael addition of β-ketoesters
-
Michael addition of various β-ketoesters with several Michael acceptors in water containing 5 mol% of a nonionic base such as phosphazenes, guanidines, and more classical nitrogen containing derivatives or triphenyl phosphine results in high yield convers
- Bensa, David,Rodriguez, Jean
-
p. 1515 - 1533
(2007/10/03)
-
- Fe3+-exchanged fluorotetrasilicic mica as an active and reusable catalyst for Michael reaction
-
Fe3+-exchanged fluorotetrasilicic mica acts as a highly effective and reusable catalyst for the solventless Michael reaction of β-ketoesters with vinyl ketones under mild condition. The immobilized catalyst shows higher activity than homogeneou
- Shimizu, Ken-Ichi,Miyagi, Masato,Kan-no, Toshiki,Kodama, Tatsuya,Kitayama, Yoshie
-
p. 7421 - 7424
(2007/10/03)
-
- Indium(III) chloride catalyzed conjugate addition of 1,3-dicarbonyl compounds to α,β-unsaturated ketones
-
Indium trichloride catalyzes efficiently the Michael reactions of 1,3-dicarbonyl compounds with α,β-unsaturated ketones to afford the corresponding Michael adducts in high yields with high selectivity.
- Yadav,Geetha,Subba Reddy
-
p. 3519 - 3524
(2007/10/03)
-
- New auxiliaries for copper-catalyzed asymmetric Michael reactions: Generation of quaternary stereocenters at room temperature
-
Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1. undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess). The exclusion of moisture or oxygen is not necessary. The auxiliaries 2 are readily available by standard procedures. After workup they can be recovered almost quantitatively.
- Christoffers, Jens,Mann, Alexander
-
p. 1014 - 1027
(2007/10/03)
-
- Tandem conjugate reduction-aldol cyclization using stryker's reagent
-
(formula presentation) Conjugate reduction by Stryker's reagent to form copper enolates, followed by intramolecular aldol cyclization, successfully generated five- and six-membered carbocycles in one pot efficiently. This tandem reaction is generally dias
- Chiu, Pauline,Szeto, Chun-Pong,Geng, Zhe,Cheng, Kin-Fai
-
p. 1901 - 1903
(2007/10/03)
-
- Highly efficient phosphazene base-catalyzed Michael addition of β-ketoesters in water
-
Michael addition of various β-ketoesters with several Michael acceptors in water containing 10 mol% of N-phenyltris(dimethylamino)iminophosphorane results in high yield conversion to the corresponding adducts.
- Bensa, David,Brunel, Jean-Michel,Buono, Gérard,Rodriguez, Jean
-
p. 715 - 717
(2007/10/03)
-
- Pentacoordinate organosilicate-catalyzed Michael addition of β-keto esters to 3-buten-2-one
-
The Michael addition of β-keto esters to 3-buten-2-one (methyl vinyl ketone, MVK) in the presence of a pentacoordinate organosilicate was investigated. Ethyl 2-oxo-1-cyclohexanecarboxylate reacted with MVK in the presence of potassium bis(1,2-benzenediola
- Tateiwa, Jun-Ichi,Hosomi, Akira
-
p. 1445 - 1448
(2007/10/03)
-
- New chiral auxiliaries for the construction of quaternary stereocenters by copper-catalyzed Michael reactions
-
The construction of quaternary stereocenters with 95-99% ee at ambient temperatures can be achieved by a copper-catalyzed Michael reaction with the application of α-amino acid amides as chiral auxiliaries [Eq. (1)]. These amides can be obtained in a few steps from the α-amino acids with standard transformations and, after the Michael reaction, they can be quantitatively recovered. Exclusion of water and oxygen is not necessary.
- Christoffers, Jens,Mann, Alexander
-
p. 2752 - 2754
(2007/10/03)
-
- Construction of quaternary stereocenters by nickel-catalysis of asymmetric Michael reactions
-
Quaternary stereocenters were constructed with an enantio-selectivity of up to 91‰ ee under aerobic conditions and at ambient temperature in the Michael reaction of β-dicarbonyl compounds and methyl vinyl ketone with Ni(OAc)2·4H2O an
- Christoffers, Jens,Roessler, Ulrich,Werner, Thomas
-
p. 701 - 705
(2007/10/03)
-
- Michael reactions in water using amphiphilic resin-supported quaternary ammonium hydroxides
-
Quaternary ammonium hydroxides were immobilized on a polystyrene-poly(ethylene glycol) copolymer resin. The amphiphilic polymer-supported ammonium hydroxides catalyzed Michael reaction of cyclic β-keto esters with several Michael acceptors in water to giv
- Shibatomi,Nakahashi,Uozumi
-
p. 1643 - 1645
(2007/10/03)
-
- Michael reactions in water using Lewis acid-surfactant-combined catalysts
-
Michael reactions in water using Lewis acid-surfactant-combined catalysts (LASCs) have been developed. In the presence of a catalytic amount of scandium tris(dodecyl sulfate) (STDS), reactions of various β-ketoesters with enones proceeded smoothly in wate
- Mori, Yuichiro,Kakumoto, Kentaro,Manabe, Kei,Kobayashi, Shu
-
p. 3107 - 3111
(2007/10/03)
-
- A study on the phase transfer catalysed Michael addition
-
Solvent-free and liquid-liquid PTC conditions have been used for the Michael addition of several enolates to methyl vinyl ketone, chalcone and methyl acrylate. The solvent-free technique affords high yields whereas the liquid-liquid procedure is less effi
- Diez-Barra, Enrique,De La Hoz, Antonio,Merino, Sonia,Rodriguez, Ana,Sanchez-Verdu, Prado
-
p. 1835 - 1844
(2007/10/03)
-
- Cu(II)-catalyzed Michael addition of 1,3-dicarbonyl compounds
-
Copper sulphate pentahydrate catalyses the C-C bond formation via Michael addition of 1,3-dicarbonyl compounds 1 under mild and neutral conditions at ambient temperature and furnishes the products 3 in high yields.
- Baruah, Partha P.,Boruah, Anima,Prajapati, Dipak,Sandhu, Jagir S.
-
p. 425 - 426
(2007/10/03)
-
- Supported phenolates as efficient catalysts of the Michael reaction
-
Simple, heterogeneous base catalysts based on supported phenolates can be easily prepared and are very active and selective in the Michael reaction.
- Macquarrie, Duncan J.
-
p. 4125 - 4128
(2007/10/03)
-
- Novel potential enantioselective phase transfer catalysts based on lupinine
-
Ten N-alkylated lupininium derivatives 5-8 were prepared as potential enantioselective phase transfer catalysts. Compounds 5a-d, 6a-d contain four asymmetric centers (including one in the side chain) with known configuration resting on an X-ray structure.
- Dehmlow, Eckehard Volker,Klauck, Robert,Neumann, Beate,Stammler, Hans-Georg
-
experimental part
p. 572 - 575
(2011/10/09)
-
- Yb(OTf)3-catalyzed Michael addition reactions of β-ketoesters on silica gel supports and at high pressure
-
Michael addition reactions of β-ketoesters with a variety of α,β-unsaturated carbonyl compounds proceed efficiently using a Yb(OTf)3 catalyst either on a silica gel support or at high pressure.
- Kotsuki, Hiyoshizo,Arimura, Koji
-
p. 7583 - 7586
(2007/10/03)
-
- Iron(III) catalysis of the Michael reaction of 1,3-dicarbonyl compounds and enones
-
Iron(III) chloride hexahydrate catalyses the Michael reaction of β-dicarbonyl compounds and enones under mild and neutral conditions with excellent yields and product selectivity.
- Christoffers, Jens
-
p. 943 - 944
(2007/10/03)
-
- Novel chemoselective and diastereoselective iron(III)-catalysed Michael reactions of 1,3-dicarbonyl compounds and enones
-
Iron(III) chloride hexahydrate catalyses the Michael reaction of 1,3-dicarbonyl compounds with α,β-unsaturated ketones under mild and neutral conditions with extraordinary efficiency. The chemoselectivity of this FeIII-catalysed process is superior to that of the classic base-catalysed Michael reaction, since the latter suffers from various side reactions, namely drawbacks such as aldol cyclisations and ester solvolysis. Excellent yields and chemoselectivities together with the environmentally friendly nature of FeIII catalysis makes this an important alternative to classic base catalysis. Moreover, the reaction procedure is reasonably easy: FeIII catalysis does not require inert or anhydrous conditions, and in most cases no solvent is needed. In terms of diastereoselectivity, the FeIII-mediated reaction may also prove superior to a base-catalysed one. In at least one example, FeIII catalysis forms a diastereoisomer as the major kinetic product, which is disfavoured in the base-mediated Michael reaction, where a thermodynamic mixture is obtained. The relative configuration of the diastereoisomeric Michael products has been determined for two examples by synthesis and structure elucidation of the cyclic aldol derivatives.
- Christoffers, Jens
-
p. 3141 - 3149
(2007/10/03)
-
- Supported BINOLate salts as base catalysts. Preparation and use in the Michael reaction
-
Two silica supported BINOL complexes are prepared, both of which are active catalysts in the Michael reaction.
- Macquarrie, Duncan J.
-
p. 601 - 602
(2007/10/03)
-
- Catalytic asymmetric Michael reaction promoted by the La-Na-BINOL complex (LSB). Enantioface selection on Michael donors
-
LSB can efficiently promote catalytic asymmetric Michael reactions in CH2Cl2, inducing high enantiomeric excesses on the Michael donor side. The multifunctional character of LSB appears to give rise to high stereoselectivity, offerin
- Sasai, Hiroaki,Emori, Eita,Arai, Takayoshi,Shibasaki, Masakatsu
-
p. 5561 - 5564
(2007/10/03)
-
- Ytterbium triflate catalyzed Michael additions of β-ketoesters in water
-
Michael addition of various β-ketoesters towards enones and α,β-unsaturated aldehydes resulted in quantitative conversion to the corresponding 1,4-adducts by performing the reactions in water in the presence of ytterbium triflate as a water-tolerant Lewis
- Keller, Erik,Feringa, Ben L.
-
p. 1879 - 1882
(2007/10/03)
-
- Facile enantioselective synthesis of two new bicyclic chiral templates
-
Optically active bicyclic dienes, 4 and 5 have been enantioselectively prepared in three and four steps, respectively. Mixtures of predominantly either the R or S enantiomer were obtained via an asymmetric alkylation of a chiral enamine.
- Belfield,Seo
-
p. 461 - 466
(2007/10/02)
-
- A facile synthesis of 1,5-diketones from cyclic β-ketoesters under nickel-catalysis
-
Michael addition of cyclic β-ketoesters to α,β-unsaturated ketones has been carried out conveniently using bis(2,4-pentanedionato)nickel(II) catalyst.
- Rao, H. Surya Prakash,Reddy, K. Subba,Jeyalakshmi, K.
-
p. 809 - 810
(2007/10/03)
-
- A new method for the preparation of Michael adducts and cyclic enones using lithium chloride-hexamethylphosphoramide system
-
A new procedure using lithium chloride in hexamethylphosphoramide was found to be useful for the synthesis of Michael-type adducts and cyclic enones. Selectivity for the two products could be controlled by altering the reaction temperature employed. The urea-type solvents were also examined instead of hexamethylphosphoramide.
- Ozaki,Kubo,Okamura,Kim
-
p. 734 - 737
(2007/10/02)
-