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Nucleophile attack

The Claisen condensation is initiated by deprotonation of an ester molecule by sodium ethanolate to give a carbanion that is stabilized, mostly by resonance, as an enolate. This carbanion makes a nucleophilic attack at the partially positively charged carbon atom of the e.ster group, leading to the formation of a C-C bond and the elimination ofan ethanolate ion, This Claisen condensation only proceeds in strongly basic conditions with a pH of about 14. [Pg.561]

Fig. 11.37 Free energy profile for the nucleophilic attack of water on CO2 (a) in aqueous solution and (b) in the enzyme carbonic anhydrase. (Graphs redrawn from Aqvist J, M Fothergill and A Warshel 1993. Computer Simulai of the COj/HCOf Interconversion Step in Human Carbonic Anhydrase I. Journal of the American Chemical Society 115 631-635.)... Fig. 11.37 Free energy profile for the nucleophilic attack of water on CO2 (a) in aqueous solution and (b) in the enzyme carbonic anhydrase. (Graphs redrawn from Aqvist J, M Fothergill and A Warshel 1993. Computer Simulai of the COj/HCOf Interconversion Step in Human Carbonic Anhydrase I. Journal of the American Chemical Society 115 631-635.)...
This thesis has been completely devoted to catalysis by relatively hard catalysts. When aiming at the catalysis of Diels-Alder reactions, soft catalysts are not an option. Soft catalysts tend to coordinate directly to the carbon - carbon double bonds of diene and dienophile, leading to an activation towards nucleophilic attack rather than to a Diels-Alder reaction . This is unfortunate, since in water, catalysis by hard catalysts suffers from a number of intrinsic disadvantages, which are absent for soft catalysts. [Pg.163]

Facile reaction of a carbon nucleophile with an olefinic bond of COD is the first example of carbon-carbon bond formation by means of Pd. COD forms a stable complex with PdCl2. When this complex 192 is treated with malonate or acetoacetate in ether under heterogeneous conditions at room temperature in the presence of Na2C03, a facile carbopalladation takes place to give the new complex 193, formed by the introduction of malonate to COD. The complex has TT-olefin and cr-Pd bonds. By the treatment of the new complex 193 with a base, the malonate carbanion attacks the cr-Pd—C bond, affording the bicy-clo[6.1,0]-nonane 194. The complex also reacts with another molecule of malonate which attacks the rr-olefin bond to give the bicyclo[3.3.0]octane 195 by a transannulation reaction[l2.191]. The formation of 194 involves the novel cyclopropanation reaction of alkenes by nucleophilic attack of two carbanions. [Pg.47]

Interestingly, some nucleophiles attack the central carbon of the 7r-allyl system to form a palladacyclobutane 316 and its reductive elimination gives... [Pg.63]

Two monomeric and dimeric 2-substituied 7r-allylic complexes (548 and 549) are obtained by treatment of allene with PdCl2(PhCN)2. They are formed by the nucleophilic attack at the central carbon of allene[493, 494],... [Pg.102]

Formation of carboxylic acids ami their derivatives. Aryl and alkenyl halides undergo Pd-catalyzed carbonylation under mild conditions, offering useful synthetic methods for carbonyl compounds. The facile CO insertion into aryl- or alkenylpalladium complexes, followed by the nucleophilic attack of alcohol or water affords esters or carboxylic acids. Aromatic and a,/ -unsaturated carboxylic acids or esters are prepared by the carbonylation of aryl and alkenyl halides in water or alcohols[30l-305]. [Pg.188]

No reaction of soft carbon nucleophiles takes place with propargylic acet-ates[37], but soft carbon nucleophiles, such as / -keto esters and malonates, react with propargylic carbonates under neutral conditions using dppe as a ligand. The carbon nucleophile attacks the central carbon of the cr-allenylpal-ladium complex 81 to form the rr-allylpalladium complex 82, which reacts further with the carbon nucleophile to give the alkene 83. Thus two molecules of the a-monosubstituted /3-keto ester 84, which has one active proton, are... [Pg.465]

Charge diagrams suggest that the 2-amino-5-halothiazoles are less sensitive to nucleophilic attack on 5-position than their thiazole counterpart. Recent kinetic data on this reactivity however, show, that this expectation is not fulfilled (67) the ratio fc.. bron.c.-2-am.noih.azoie/ -biomoth.azoie O"" (reaction with sodium methoxide) emphasizes the very unusual amino activation to nucleophilic substitution. The reason of this activation could lie in the protomeric equilibrium, the reactive species being either under protomeric form 2 or 3 (General Introduction to Protomeric Thiazoles). The reactivity of halothiazoles should, however, be reinvestigated under the point of view of the mechanism (1690). [Pg.18]

The reaction of propiolic acid or its esters with 2-aminothiazole yields 7H-thiazolo[3.2o]pyTimidine 7-one (109) (Scheme 74) (273), The reaction probably proceeds by initial nucleophilic attack of 2-aminothiazole on the sp C followed by intramolecular addition of ring nitrogen to spC. [Pg.53]

Acidic hydrolysis of 2,5-dipheny]-4-aminothiazole similarly gives product 233, resulting from nucleophilic attack on C-4 (Scheme 142) (465). [Pg.85]

Thiazolotriazepines (290) are prepared by reaction in cold pyridine of the product resulting from nucleophilic attack of I-hydrazinothiazole on... [Pg.101]

The electrophilic character of the C-2 atom is more clearly evident in A-4-thiazoline-2-ones than in A-4-thiazoline-2-thiones. 3-Mcthyl-A-4-thiazoline-2-one is cleaved in alcaline medium to give methylaraine (36). This reaction probably starts with the nucleophilic attack of OH on C-2. [Pg.401]

Reduction of A-4-thiazoline-2-one by zinc dust gives low yields of the corresponding thiazoles (36, 231). The formation of thiochrome (95) results from an intramolecular nucleophilic attack (Scheme 47) (232). [Pg.402]

In a third step, the anhydrobase reacts on the carbon which is the most sensitive to nucleophilic attack. The unstable intermediate 23 splits into aminothiophenol and trimethine thiazolocyanine 124). [Pg.43]

As a consequence of the alternative distribution of an even number (2n) TT electrons on an odd number (2n - 1) carbon atoms, centers of the methine chain susceptible to nucleophilic attack are effectively the even carbons atoms starting from nitrogen, as it has been proven experimentally (103), particularly with a ketomethyiene giving a neutrocyanine compound (53, 67). [Pg.72]

The activated position is the most vulnerable to nucleophilic attack... [Pg.525]

Ilvespaa (98) has demonstrated that, using some amines, the 2-chloro-5-nitrothiazole undergoes an opening reaction in a competitive reaction parallel to the normal substitution process. This confirms the sensitivity of position 4 to nucleophilic attack when a nitro group is present in position 5 (Scheme 16). [Pg.579]

Step 2 Anion of hydrogen peroxide acts as a nucleophile attacking boron and forming an oxygen-boron bond... [Pg.255]

Step 2 Nucleophilic attack of bromide anion on the bromonium ion... [Pg.257]

Step 2 of the mechanism m Figure 6 12 is a nucleophilic attack by Br at one of the carbons of the cyclic bromonium ion For reasons that will be explained m Chapter 8 reactions of this type normally take place via a transition state m which the nude ophile approaches carbon from the side opposite the bond that is to be broken Recall mg that the vicinal dibromide formed from cyclopentene is exclusively the trans stereoisomer we see that attack by Br from the side opposite the C—Br bond of the bromonium ion intermediate can give only trans 1 2 dibromocyclopentane m accordance with the experimental observations... [Pg.258]

In a second possibility illustrated in Figure 8 Ih the nucleophile attacks the sub state from the side opposite the bond to the leaving group This is called back side dis placement or substitution with inversion of configuration... [Pg.331]

FIGURE 8 1 Two contrast mg stereochemical pathways for substitution of a leaving group (red) by a nucleophile (blue) In (a) the nucleophile attacks carbon at the same side from which the leaving group departs In (b) nude ophilic attack occurs at the side opposite the bond to the leaving group... [Pg.332]

As we have seen the nucleophile attacks the substrate m the rate determining step of the Sn2 mechanism it therefore follows that the rate of substitution may vary from nucleophile to nucleophile Just as some alkyl halides are more reactive than others some nucleophiles are more reactive than others Nucleophilic strength or nucleophilicity, is a measure of how fast a Lewis base displaces a leaving group from a suitable substrate By measuring the rate at which various Lewis bases react with methyl iodide m methanol a list of then nucleophihcities relative to methanol as the standard nucleophile has been compiled It is presented m Table 8 4... [Pg.337]

Tertiary alkyl halides are so sterically hindered to nucleophilic attack that the pres ence of any anionic Lewis base favors elimination Usually substitution predominates over elimination m tertiary alkyl halides only when anionic Lewis bases are absent In the solvolysis of the tertiary bromide 2 bromo 2 methylbutane for example the ratio of substitution to elimination is 64 36 m pure ethanol but falls to 1 99 m the presence of 2 M sodium ethoxide... [Pg.349]

Section 10 10 Protonation at the terminal carbon of a conjugated diene system gives an allylic carbocation that can be captured by the halide nucleophile at either of the two sites that share the positive charge Nucleophilic attack at the carbon adjacent to the one that is protonated gives the product of direct addition (1 2 addition) Capture at the other site gives the product of conjugate addition (1 4 addition)... [Pg.417]

A key step in the reaction mechanism appears to be nucleophilic attack on the alkyl halide by the negatively charged copper atom but the details of the mechanism are not well understood Indeed there is probably more than one mechanism by which cuprates react with organic halogen compounds Vinyl halides and aryl halides are known to be very unreactive toward nucleophilic attack yet react with lithium dialkylcuprates... [Pg.604]

When applied to the synthesis of ethers the reaction is effective only with primary alcohols Elimination to form alkenes predominates with secondary and tertiary alcohols Diethyl ether is prepared on an industrial scale by heating ethanol with sulfuric acid at 140°C At higher temperatures elimination predominates and ethylene is the major product A mechanism for the formation of diethyl ether is outlined m Figure 15 3 The individual steps of this mechanism are analogous to those seen earlier Nucleophilic attack on a protonated alcohol was encountered m the reaction of primary alcohols with hydrogen halides (Section 4 12) and the nucleophilic properties of alcohols were dis cussed m the context of solvolysis reactions (Section 8 7) Both the first and the last steps are proton transfer reactions between oxygens... [Pg.637]

Step 2 Nucleophilic attack by a molecule of alcohol on the alkyloxonmm ion formed m step 1 CH3CH2... [Pg.637]


See other pages where Nucleophile attack is mentioned: [Pg.561]    [Pg.140]    [Pg.628]    [Pg.632]    [Pg.222]    [Pg.38]    [Pg.66]    [Pg.87]    [Pg.410]    [Pg.8]    [Pg.40]    [Pg.41]    [Pg.140]    [Pg.209]    [Pg.164]    [Pg.335]    [Pg.336]    [Pg.445]   
See also in sourсe #XX -- [ Pg.8 , Pg.16 , Pg.34 , Pg.48 , Pg.75 , Pg.94 , Pg.135 , Pg.144 , Pg.164 , Pg.170 , Pg.178 , Pg.181 , Pg.191 , Pg.205 ]




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1-Haloalkynes, nucleophilic attacks

13- Lactam nucleophilic attack

13- Lactam nucleophilic attack, intramolecular

2- Azetidinones nucleophilic attack

2-Alkyl-3-isothiazolinones, nucleophilic attack

2-Oxetanones nucleophilic attack

A Nucleophilic Attack on Carbon

Acetate nucleophilic attack

Acetylenes nucleophilic attack

Acid-catalyzed nucleophilic attack at carbon

Acridine nucleophilic attack

Activation of a Substrate toward Nucleophilic Attack

Acyl nucleophile attack

Aldehydes nucleophilic attack

Alkene complexes nucleophilic attack

Alkene ligands nucleophilic attack

Alkenes coordinated, nucleophilic attack

Alkenes nucleophilic attack

Alkyl groups, nucleophilic attack

Alkyl ligands nucleophilic attack

Alkylidenes nucleophilic attack

Alkylidynes nucleophilic attack

Alkyne complexes nucleophilic attack

Alkynes nucleophilic attack

Alkynes, nucleophilic attack upon

Allene complexes nucleophilic attack

Allyl Complexes by Nucleophilic Attack

Allyl complexes nucleophilic attacks

Allyl ligand, nucleophilic attack

Allylic compounds, nucleophilic attack

Allylic systems, nucleophilic attack

Amines nucleophilic attack

Anthracene nucleophilic attack

Arenes nucleophilic attack

Aryl groups, nucleophilic attack

Attack by Nucleophiles

Attack of nucleophile

Azine substitution —cont by nucleophilic attack

Aziridines nucleophilic attack

Azlactones nucleophilic attack

Benzofuroxans nucleophilic attack

Bonding nucleophilic attack

Bonds nucleophilic attack

By nucleophilic attack onto carbonyl groups

Cage Helicity and Further Consequences Nucleophilic Attack on Quinuclidin-3-ones

Carbenes nucleophilic attack

Carbon monoxide nucleophilic attack

Carbon nitrogen nucleophile attack

Carbon nucleophilic attack

Carbonyl activation, nucleophilic attack

Carbonyl clusters, nucleophilic attack

Carbonyl compounds nucleophilic attack

Carbonyl group nucleophilic attack

Carbonylation nucleophilic attack

Carboxamides nucleophilic attack

Carboxylic acid derivatives, nucleophilic attack

Carbyne complexes nucleophilic attack

Cascade intramolecular nucleophilic attack

Chalcogen nucleophilic attack

Chromium carbonyl nucleophilic attack

Cieplak nucleophilic attack

Cobalt complexes nucleophilic attack

Coordinated ligand, nucleophilic attack

Cyclative cleavage nucleophile attack

Cyclohexanones nucleophilic attack

Cysteine in Nucleophilic Attack

Diastereoselective Nucleophilic and Electrophilic Attack on Double Bonds Free of Steric Effects

Diene complexes nucleophilic attack

Dienes nucleophilic attack

Dinitrogen nucleophilic attack

Electronegative elements nucleophilic attack

Electrophiles nucleophilic attack

Electrophilicity nucleophilic attack

Electropositive element nucleophilic attack

Elimination happens when the nucleophile attacks hydrogen instead of carbon

Epoxides nucleophilic attack

Ethyl acrylate nucleophilic attack

External attack of nucleophiles on alkene coordinated to electrophilic metal complexes

From 1,2 dienes nucleophilic attack

Frontside nucleophilic attack

Glutamate-43, nucleophilic attack

Glycals nucleophilic attack

Haloarenes nucleophilic attack

Halodeoxy sugars nucleophilic attack

Heterocyclic intramolecular nucleophilic attack

Hiickel calculations nucleophilic attack

Hydroxide, nucleophilic attack

Imine complexes nucleophilic attack

Imines nucleophilic attack

Iminium ions, nucleophilic attack

Intermolecular reactions nitrogen nucleophile attacks

Intermolecular reactions oxygen nucleophile attacks

Intramolecular nucleophilic attack Subject

Irene complexes nucleophilic attack

Iron nitrosyls nucleophilic attack

Isonitriles nucleophilic attack

Ketones nucleophilic attack

Lactones nucleophilic attack

Ligand substitution reactions nucleophilic attack

Ligands nucleophilic attack

Maleic anhydride nucleophilic attack

Masochistic nucleophilic attack

Metal carbonyls nucleophilic attack

Metal-activated nucleophilic attack

Metathesis nucleophilic attack

Methyl acrylate nucleophilic attack

Methyl group nucleophilic attack

Methyl nucleophilic attack

Methyl vinyl ketone nucleophilic attack

Methylplatinum complexes nucleophilic attack

Migration-nucleophilic attack-cyclization

NUCLEOPHILIC ATTACK ON PROTONS ATTACHED TO RING ATOMS

NUCLEOPHILIC ATTACK ON RING CARBON ATOMS

NUCLEOPHILIC ATTACK ON RING HETEROATOMS

Nitric oxide nucleophilic attack

Nitriles nucleophilic attacks

Nitrogen nucleophiles catalysis, intramolecular attacks

Nucleophile Nucleophilic attack

Nucleophile Nucleophilic attack

Nucleophiles attack

Nucleophiles attack

Nucleophiles transition-metal complexes attacked

Nucleophilic Attack Other Than at the Metal Atom

Nucleophilic Attack at CO Ligands

Nucleophilic Attack at Halogen

Nucleophilic Attack at Hydrogen

Nucleophilic Attack at Other Atoms

Nucleophilic Attack at Phosphorus

Nucleophilic Attack at Ring Carbon

Nucleophilic Attack at Ring Nitrogen

Nucleophilic Attack at Ring Sulfur

Nucleophilic Attack at the Ligands

Nucleophilic Attack by Oxygen

Nucleophilic Attack by Phosphorus

Nucleophilic Attack on Carbon

Nucleophilic Attack on Co-ordinated Nitriles

Nucleophilic Attack on Coordinated Double Bonds

Nucleophilic Attack on Halogen

Nucleophilic Attack on Hydrogen Attached to Carbon

Nucleophilic Attack on Hydrogen Proton Abstraction)

Nucleophilic Attack on N Aromatics Pyrrole and Pyridine

Nucleophilic Attack on Other Atoms

Nucleophilic Attack on Ring Carbon

Nucleophilic Attack on Ring Hydrogen (Proton Abstraction)

Nucleophilic Attack on Sulfur

Nucleophilic Attack on Transition Metal Complexes of Carbon Monoxide and Isonitriles

Nucleophilic Attack on Z-Substituted Benzenes

Nucleophilic Attack on a Carbonyl Group

Nucleophilic Attack on a Coordinated Ligand

Nucleophilic Attack on a Ligand

Nucleophilic Attack on a Temporarily Formed Imino Group

Nucleophilic Attack on the Ligands

Nucleophilic amidines, attack

Nucleophilic and Electrophilic Attack on Cycloalkenes

Nucleophilic and electrophilic attack

Nucleophilic attack

Nucleophilic attack

Nucleophilic attack 4- coordinate complexes

Nucleophilic attack 5- coordinate intermediate structure

Nucleophilic attack 5-coordination site involvement

Nucleophilic attack Ritter reaction

Nucleophilic attack Subject

Nucleophilic attack activation parameters

Nucleophilic attack alkyl halides

Nucleophilic attack at carbon

Nucleophilic attack at coordinated ligand

Nucleophilic attack at hydrogen (Deprotonation)

Nucleophilic attack at silicon

Nucleophilic attack at sulfur

Nucleophilic attack at the carbonyl group

Nucleophilic attack bimolecular transfer

Nucleophilic attack by hydride on

Nucleophilic attack by hydride on aldehydes and ketones

Nucleophilic attack by metal

Nucleophilic attack by unsaturated carbon

Nucleophilic attack carbonium ions

Nucleophilic attack catalysis

Nucleophilic attack chiral enolate

Nucleophilic attack complex rate laws

Nucleophilic attack concerted mechanism

Nucleophilic attack conjugate base mechanism

Nucleophilic attack equilibrium conditions

Nucleophilic attack fluxionality

Nucleophilic attack fundamental principles

Nucleophilic attack gold complexes

Nucleophilic attack halogen molecules

Nucleophilic attack hydrocarbon complexes

Nucleophilic attack initiation

Nucleophilic attack initiation characteristics

Nucleophilic attack initiation kinetics

Nucleophilic attack initiation mechanism

Nucleophilic attack intimate mechanisms

Nucleophilic attack intramolecular

Nucleophilic attack ligand-dependent pathway

Nucleophilic attack metal-olefin complexes

Nucleophilic attack nickel complexes

Nucleophilic attack of aldehydes and ketones

Nucleophilic attack of carbonyls

Nucleophilic attack of methoxide

Nucleophilic attack olefins

Nucleophilic attack on activated

Nucleophilic attack on allylic compounds

Nucleophilic attack on carbonyl groups

Nucleophilic attack on carbonyls

Nucleophilic attack on coordinated

Nucleophilic attack on coordinated ligands

Nucleophilic attack on coordinated olefins

Nucleophilic attack on epoxide

Nucleophilic attack on organotransition

Nucleophilic attack on organotransition metal complexes

Nucleophilic attack orbital interactions controlling

Nucleophilic attack orbital overlap

Nucleophilic attack oxidation

Nucleophilic attack oxidative addition reactions

Nucleophilic attack palladium complexes

Nucleophilic attack physical properties

Nucleophilic attack platinum complexes

Nucleophilic attack polar solvent effect

Nucleophilic attack reactions

Nucleophilic attack reduction reactions

Nucleophilic attack regiospecificity

Nucleophilic attack relative reactivities

Nucleophilic attack reverse hydrolysis

Nucleophilic attack rhodium compounds

Nucleophilic attack solubility

Nucleophilic attack solvation

Nucleophilic attack stability

Nucleophilic attack stereoselectivity

Nucleophilic attack steric effects

Nucleophilic attack substitution

Nucleophilic attack tetrahedral carbon center

Nucleophilic attack transition metal complexes

Nucleophilic attack trigonal bipyramids

Nucleophilic attack trigonal-bipyramidal transition state

Nucleophilic attack types

Nucleophilic attack via single-electron transfer

Nucleophilic attack, 1,2-dithiolium ring

Nucleophilic attack, electron transfer reactions

Nucleophilic attack, ester hydrolysis

Nucleophilic attack, glutathione conjugation

Nucleophilic attack, of water molecules

Nucleophilic attack, propargylic centers

Nucleophilic attacks isocyanide complexes

Nucleophilic attacks nitrile complexes

Nucleophilic attacks phosphate esters

Nucleophilic back-side* attack

Nucleophilic substitution ligand attacks

Nucleophilic ‘front-side’ attack

Nucleophilic-electrophilic attack at coordinated carbonyls

Olefin complexes nucleophilic attack

Olefin complexes nucleophilic attack upon

Orientation of nucleophilic attacks

Orthoesters, nucleophilic attack

Oxazoles nucleophilic attack

Oxonium ions, nucleophilic attack

Oxygen nucleophiles intramolecular attacks

Palladium complexes olefin, nucleophilic attack

Palladium nucleophilic attack

Palladium promotion of nucleophilic attack

Palladium-allyl complexes nucleophilic attacks

Perfluoroalkenes nucleophilic attack

Polyenes open, nucleophilic attack

Pyridazine 1-oxides, nucleophilic attack

Pyridine nucleophilic attack

Pyridinium cations nucleophilic attack

Pyrrole nucleophilic attack

Quinoline nucleophilic attack

Reactivity with the Attacking Nucleophile

Relative rates of nucleophilic attack

Replacement by Nucleophilic Attack

Reversibility of nucleophilic attack

Ring closure by nucleophilic attack

Ruthenium nitrosyls nucleophilic attack

Stereochemistry of nucleophilic attack

Succinimide, nucleophilic attack

Terminal acetylenes nucleophilic attacks

Tetrahedral nucleophilic attack

The Attacking Nucleophile

The Direction of Nucleophilic Attack and Orbital Steering

The angle of nucleophilic attack on aldehydes and ketones

The site of nucleophilic attack

Thioesters nucleophilic attack

Thiolactones nucleophilic attack

Titanium isopropoxide nucleophilic attack

Transition metal clusters and nucleophilic attack

Water, nucleophilic attack

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