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Asymmetric, catalysts

Fig. 1. P MAS NMR spectrum of (a)Ru-BrNAP/PTA/y-Al203, and (b)Ru-BINAP crt rlex In order to find the characteristics of the immobilized catalyst, asymmetric hydrogenation of the prochiral C=C bond was performed as a model reaction. Firstly, three different homogeneous Ru-BINAP complexes including [RuCl2((R)-BINAP)], [RuCl((R)-BINAP)(p-cymene)]Cl and [RuCl((R)-BINAP)(Benzene)]Cl were immobilized on the PTA-modified alumina. Reaction test of immobilized catalysts showed that [RuCl2((R)-BINAP)] was the most active and selective so all the experiment were done using this catalyst afterwards. Fig. 1. P MAS NMR spectrum of (a)Ru-BrNAP/PTA/y-Al203, and (b)Ru-BINAP crt rlex In order to find the characteristics of the immobilized catalyst, asymmetric hydrogenation of the prochiral C=C bond was performed as a model reaction. Firstly, three different homogeneous Ru-BINAP complexes including [RuCl2((R)-BINAP)], [RuCl((R)-BINAP)(p-cymene)]Cl and [RuCl((R)-BINAP)(Benzene)]Cl were immobilized on the PTA-modified alumina. Reaction test of immobilized catalysts showed that [RuCl2((R)-BINAP)] was the most active and selective so all the experiment were done using this catalyst afterwards.
This chapter deals with recent developments in this area, in particular DKR by enzyme-metal combinations. Each successful DKR is exempfified with several substrates and novel metal catalyst. Asymmetric transformations of achiral substrates via DKR of racemic intermediates also are described. [Pg.60]

Scheme 8-44. General scheme for Ti-catalyst asymmetric glyoxylate-ene reactions. Reprinted with permission by Wiley-VCH Verlag GmbH, Ref. 89. Scheme 8-44. General scheme for Ti-catalyst asymmetric glyoxylate-ene reactions. Reprinted with permission by Wiley-VCH Verlag GmbH, Ref. 89.
In contrast to the maturity of asymmetric synthesis utilizing chiral transition metal catalysts, asymmetric phase transfer catalysis is still behind it and covers organic reactions to lesser extent. Thus, it is further necessary in wide range to explore efficient asymmetric phase transfer catalysis keeping its superiority of easy operation, mild reaction conditions, and environmental binignancy. [Pg.140]

CAMPHOS catalyst, asymmetric hydrogenation of a,p-unsaturated carboxlic acids, 25 107-109, 112 -carbon bond, COj insertion, 28 132-134 -carbon dioxide complex, coordination, 28 125, 126, 128 oxide formation, 28 27 as catalyst, 26 335... [Pg.189]

A review of enantioselective aldol additions of latent enolate equivalents covers a variety of Sn", boron, Ti, Cu, lanthanide, and Lewis base catalysts. Asymmetric aldol reactions using boron enolates have been reviewed (401 references). ... [Pg.11]

When ethyl cyanoformate was used as the cyanide source and a heterobimetallic YLi3(binaphthoxide) complex (YLB) (Figure 5.15) was used as catalyst, asymmetric cyanoethoxycarbonylations of aldehydes were achieved in high yields and enantioselectivities in the presence of three achiral additives water, tris(2,6-... [Pg.147]

Huang YJ, Yang FY, Zhu CJ (2005) Highly enantioseletive biginelli reaction using a new chiral ytterbium catalyst Asymmetric synthesis of dihydropyrimidines. J Am Chem Soc 127 16386-16387... [Pg.273]

Chiral catalysts, asymmetric metal-catalyzed suHoxidations, 478-85 Chiral 1,2-dihydronaphthalenes, photooxygenation, 265-6 Chiral dioxetanes, stereoselective synthesis, 1173-8... [Pg.1450]

Makino, K., Hiroki, Y. and Hamada, Y. Dynamic Kinetic Resolution Catalyzed by Ir Axially Chiral Phosphine Catalyst Asymmetric S3mthesis of anti-Aromatic -Hydroxy-ot-amino Acid Esters. J. Am. Chem. Soc. 2005, 127, 5784—5785. [Pg.30]

As described in the preceding sections, asymmetric amplification is generally a consequence of the formation of aggregates (i.e., dimers or oligomers that are homochiral or heterochiral) of a chiral catalyst. However, even a racemic catalyst can be used as a chiral catalyst with the aid of chiral additives (a simple model consisting of dimers is depicted in Scheme 9.17). If a chiral additive (R)-B is selectively associated with (S)-A in the racemic catalyst, the remaining (R)-A could operate as the chiral monomer catalyst (asymmetric deactivation). Conversely, the chiral additive (/ )-B can be selectively associated with (/ )-A in racemic catalyst to generate an active dimeric catalyst (asymmetric activation). [Pg.708]

Barbier-type reactions, 9, 358 catalystic asymmetric reactions, 9, 359 Lewis acid-promoted reactions, 9, 358 Allenyltrichlorosilanes from 1,3-enynes, 9, 309 preparation, 9, 309... [Pg.50]

Enantioselective conjugate addition of dialkylzincs to enones using chiral catalysts asymmetric synthesis of -substituted ketones... [Pg.255]

A catalytic route using a manganese (III) complex has been developed for a-hydroxylation of ketones avoiding the use of water or a protic solvent mixtures of a-hydroxyketones and their silyl derivatives were formed in excellent yield. By using a chiral pyrrolidine-based manganese (III) complex as catalyst, asymmetric oxidation was effected, with enantiomeric excess varying from 14 to 62% [30], Another kind of a-functionalized ketones resulted from silyl enol ethers which after the addition of IOB.BF3 were treated with triethyl phosphite a-ketophosphonates were obtained in this way [31] ... [Pg.88]

Sulphides are oxidized readily by most hypervalent iodine reagents. IOB alone is not suitable, since mixtures of sulphoxides and sulphones are formed under drastic conditions. However, in the presence of catalytic amounts of p-toluenesulphonic acid [49] or benzeneseleninic acid [50] various sulphides were cleanly oxidized to sulphoxides in excellent yields. Using a chiral catalyst asymmetric oxidation was highly successful [51]. [Pg.94]

For the aziridination of 1,3-dienes, copper catalysis gave better yields of A-tosyl-2-alkenyl aziridines with 1,3-cyclooctadiene, 1,4-addition occurred exclusively (50%) [46]. Good results were also obtained on rhodium catalysed decomposition of PhI=NNs (Ns = p-nitrophenylsulphonyl) with some alkenes the aziridination was stereospecific, whereas with chiral catalysts asymmetric induction (up to 73% ee) was achieved. However, cyclohexene gave predominantly (70%) a product derived from nitrene insertion into an allylic carbon-hydrogen bond [47]. [Pg.191]

Hoveyda and co-workers have developed chiral catalysts for asymmetric alkene metathesis. They have demonstrated that with their chiral molybdenum catalyst asymmetric syntheses of dihydrofurans through catalytic kinetic resolution by RCM and enantioselective desymmetrization by RCM are feasible processes (Scheme 40) <1998JA9720>. The use of Schrock s molybdenum catalysts for asymmetric alkene metathesis has been reviewed <2001CEJ945>. [Pg.520]

Chiral Lewis Acid Catalysts Asymmetric synthesis... [Pg.3]

Enantioselective carbenoid cyclopropanation of achiral alkenes can be achieved with a chiral diazocarbonyl compound and/or chiral catalyst. In general, very low levels of asymmetric induction are obtained, when a combination of an achiral copper or rhodium catalyst and a chiral diazoacetic ester (e.g. menthyl or bornyl ester ) or a chiral diazoacetamide ° (see Section 1.2.1.2.4.2.6.3.3., Table 14, entry 3) is applied. A notable exception is provided by the cyclopropanation of styrene with [(3/ )-4,4-dimethyl-2-oxotetrahydro-3-furyl] ( )-2-diazo-4-phenylbut-3-enoate to give 5 with several rhodium(II) carboxylate catalysts, asymmetric induction gave de values of 69-97%. ° Ester residues derived from a-hydroxy esters other than ( —)-(7 )-pantolactone are not as equally well suited as chiral auxiliaries for example, catalysis by the corresponding rhodium(II) (S )-lactate provides (lS, 2S )-5 with a de value of 67%. [Pg.456]

Asymmetric catalysis encompasses the use of both biocatalysts (e.g., enzymes) and chemical catalysts that possess an element of chirality (e.g., a transition metal complex bearing a chiral ligand). From a commercial perspective, the interest in asymmetric catalysis emanates from inherent economic and ecological benefits that are associated with the capacity to produce a large volume of valuable enantiomerically enriched material through the agency of a negligible quantity of a chiral catalyst. Asymmetric catalytic processes may involve kinetic resolution of a racemic substrate, or preferably, direct transformation of a prochiral substrate into the desired chiral molecule. [Pg.339]


See other pages where Asymmetric, catalysts is mentioned: [Pg.77]    [Pg.1541]    [Pg.382]    [Pg.190]    [Pg.431]    [Pg.15]    [Pg.95]    [Pg.83]    [Pg.318]    [Pg.256]    [Pg.657]    [Pg.633]    [Pg.528]    [Pg.676]    [Pg.216]   
See also in sourсe #XX -- [ Pg.87 , Pg.113 ]

See also in sourсe #XX -- [ Pg.139 ]

See also in sourсe #XX -- [ Pg.87 , Pg.113 ]

See also in sourсe #XX -- [ Pg.139 ]




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ASYMMETRIC HYDROGENATION WITH CHIRAL RUTHENIUM CATALYSTS

Active catalyst asymmetric closure

Aldol condensation asymmetric catalysts

Alkaloid Derivatives as Asymmetric Phase-transfer Catalysts

Amino acid-derived catalysts asymmetric hydrogen transfer

Amino acid-derived catalysts asymmetric protonation

Asymmetric Activation and Deactivation of Racemic Catalysts

Asymmetric Activation of Chirally Flexible (Tropos) Catalysts

Asymmetric Activation of Racemic Catalysts

Asymmetric Aldols Catalysed by Proline, Its Derivatives and Related Catalysts

Asymmetric Allylation with the CAB Catalyst

Asymmetric Cycloaddition Catalyzed by Cinchona-Based Phase-Transfer Catalysts

Asymmetric Deactivation of Racemic Catalysts

Asymmetric Dihydroxylation Catalysts

Asymmetric Heterogeneous Catalysts Implemented in Industry

Asymmetric Hydrogenation of Prochiral Olefins by Rhodium-DuPhos Catalysts

Asymmetric Hydrogenation with Ruthenium Catalysts

Asymmetric Mannich reaction organometallic catalysts

Asymmetric Organocatalysis Introducing a Thiourea Catalyst for the Petasis Reaction

Asymmetric Reduction of Ketones Using Nonmetallic Catalysts

Asymmetric Reduction of Ketones Using Organometallic Catalysts

Asymmetric Sulfoxidation using Flavins as Catalysts

Asymmetric Transformations Using Resin-Bound Chiral Catalysts and Auxiliaries

Asymmetric alkali-metal catalyst

Asymmetric alkene catalysts

Asymmetric alkoxycarbonylation catalysts

Asymmetric aza Diels-Alder reactions synthesis of tetrahydroquinoline derivatives using a chiral lanthanide Lewis acid as catalyst

Asymmetric catalysis using polymer supported catalysts

Asymmetric catalyst directed

Asymmetric catalyst for

Asymmetric chiral catalyst-driven

Asymmetric copper catalysts

Asymmetric counteranion-directed catalysis catalysts

Asymmetric cycloaddition reaction catalysts

Asymmetric epoxidation catalyst preparation

Asymmetric epoxidation transition metal catalysts

Asymmetric homogeneous catalysts

Asymmetric hydroformylation, platinum catalysts

Asymmetric hydroformylation, rhodium catalysts

Asymmetric hydrogenation catalyst nature

Asymmetric hydrogenation catalysts

Asymmetric hydrogenation on metal-quartz catalysts

Asymmetric hydrogenations diamine catalysts

Asymmetric hydrogenations with Knowles’ catalyst

Asymmetric induction using chiral transition metal catalysts

Asymmetric induction with supported catalysts

Asymmetric metal complex catalysts

Asymmetric metal-catalyzed sulfoxidations chiral catalysts

Asymmetric multimetallic catalyst

Asymmetric osmium catalyst

Asymmetric palladium catalysts

Asymmetric phase-transfer catalysts

Asymmetric reactions, multiple catalyst-controlled

Asymmetric reduction of chloroacetophenone using a sulfoximine catalyst

Asymmetric reduction oxazaborolidine catalyst

Asymmetric reductive amination metal catalysts

Asymmetric synthesis catalyst controlled, examples

Asymmetric synthesis cyclopropanation, rhodium catalyst

Asymmetric synthesis with chiral catalysts

Asymmetric transfer hydrogenation (ATH) catalysts

Asymmetric transfer hydrogenation catalysts

Asymmetric using chiral catalysts

Asymmetric, catalysts synthesis

Bifunctional catalysts hydrogen-bond-donor asymmetric

Binaphthol, asymmetric catalyst

Bovine serum albumin asymmetric catalyst

Calcium catalysts, asymmetric

Catalysis/catalysts asymmetric reactions

Catalyst Bronsted base asymmetric

Catalyst asymmetric 430 - mass

Catalyst for asymmetric dihydroxylation

Catalysts aldol additions, catalytic asymmetric

Catalysts asymmetric hydroformylation

Catalysts asymmetric hydrogenation using

Catalysts for asymmetric reduction

Catalysts in asymmetric synthesis

Catalytic Asymmetric Aza Diels-Alder Reactions Promoted by Chiral Ytterbium Catalysts

Chiral Amines as Catalysts in Asymmetric Mannich Reactions

Chiral Catalysts for Asymmetric Allylation

Chiral catalysts, asymmetric metal-catalyzed

Chiral salen catalysts, olefins asymmetric

Cinchona-Derived Chiral Phase-Transfer Catalysts for Other Asymmetric Synthesis

Cinchona-Derived Chiral Poly(Phase-Transfer Catalysts) for Asymmetric Synthesis

Copper catalysts asymmetric reactions

Dynamic kinetic asymmetric catalysts

Dynamic kinetic asymmetric ruthenium catalyst

Ethers, Taddol, Nobin and Metal(salen) Complexes as Chiral Phase-Transfer Catalysts for Asymmetric Synthesis

Heterobimetallic asymmetric catalysts

Heterochiral catalysts, asymmetric

Heterochiral catalysts, asymmetric amplification

Heterogeneous asymmetric catalysis catalyst

Heterogeneous asymmetric catalysis chirally modified catalysts

Heterogeneous asymmetric catalysis inorganic catalysts

Heterogeneous asymmetric catalysis organic catalysts

Heterogeneous asymmetric catalysis solid catalysts

Homogeneous asymmetric catalysis dendritic catalysts

Homogeneous asymmetric catalysis polymeric catalysts

Hydrogenation, catalytic, alkene asymmetric catalysts

Iridium asymmetric catalysts

Iridium catalysts catalyzed asymmetric allylation

Keck allylation reaction asymmetric catalysts

Lanthanide Bimetallic and Polymetallic Asymmetric Catalysts

Lanthanide-Alkali Metal Heterobimetallic Asymmetric Catalysts

Meso catalysts asymmetric amplification

Multiple catalyst-controlled asymmetric

Nickel catalysts asymmetric reactions

Nonmetallic catalysts asymmetric reduction using

Novel Heterogenized Catalysts for Asymmetric Ring-Opening Reactions of Epoxides

Organometallic Catalysts in Asymmetric Mannich Reactions

Other Chiral Phase-Transfer Catalysts for Asymmetric Synthesis

Palladium catalysts catalyzed asymmetric allylation

Phase transfer catalyst asymmetric selection

Phosphine catalysts carbonates, asymmetric allylic

Phosphine-based catalysts, asymmetric

Phosphine-based catalysts, asymmetric catalysis

Polymer asymmetric aldol catalyst

Polymer-Supported Asymmetric Aldol Catalysts

Polymetallic asymmetric catalysts

Proline catalysts asymmetric aldol reactions

Purely organic catalysts asymmetric catalysis

Racemic catalysts, asymmetric amplification

Rhodium catalysts asymmetric

Rhodium catalysts asymmetric reactions

Rhodium catalysts for asymmetric ketone reduction

Rhodium catalyzed asymmetric imine hydrogenation catalysts

Rhodium complex catalysts asymmetric

Rhodium-phosphine catalysts asymmetric hydrogenation

Ring-closing metathesis asymmetric, using chiral catalyst

Ruthenium catalysts asymmetric

Ruthenium catalysts asymmetric reductive amination

Ruthenium catalysts asymmetric transfer hydrogenation

Ruthenium catalysts keto ester asymmetric hydrogenation

Ruthenium complex catalysts asymmetric

Ruthenium complex catalysts asymmetric hydrogenation

Sharpless asymmetric epoxidation Catalyst structure

Sharpless asymmetric epoxidation titanium catalysts

Supported Dendritic Catalysts for the Asymmetric Addition of Diethylzinc

The Application of DuPHOS Rhodium(l) Catalysts for Commercial Scale Asymmetric Hydrogenation

Thiamine Diphosphate-Dependent Enzymes Multi-purpose Catalysts in Asymmetric Synthesis

Titanium catalysts asymmetric epoxidation

Titanium catalysts asymmetric principles

Titanium complexes (Sharpless Ti tartrate asymmetric epoxidation catalyst)

Titanium-Binol catalyst asymmetric reactions

Transition metal catalysts asymmetric reductive amination

Transition metal catalysts asymmetric sulfoxidation

Two-Center Chiral Phase-Transfer Catalysts for Asymmetric Synthesis

Type I Homochiral MOCP Catalysts in Heterogeneous Asymmetric Reactions

Type II Homochiral MOCP Catalysts in Heterogeneous Asymmetric Reactions

Use of Nobin and Related Species as Asymmetric Phase-Transfer Catalysts

Use of asymmetric catalysts

Vanadium catalysts allylic alcohol asymmetric epoxidation

Vanadium catalysts asymmetric epoxidation

Zinc catalysts direct catalytic asymmetric aldol

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