Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
orgoexam2
Chapters 17,18,19
| Question | Answer |
|---|---|
| Alcohols contain an OH group next to a saturated ____ carbon | sp3 |
| OH groups bonded to vinylic sp2-hybridized carbons are called___ | enols |
| alcohols are both ______ and _____ depending upon the conditions of the solution | weakly basic; weakly acidic |
| Nomenclature of alcohols | take the longest carbon chain attached to the OH group and make it the parent chain. number the chain from the end nearer to the hydroxyl group. number substituents in order that the come in the chain but list them in alphabetical order in the name |
| primary alcohol | is attached to a carbon that only has one other carbon attached to it |
| secondary alcohol | attached to a carbon that has two other carbons attached to it |
| tertiary alcohol | attached to a carbon that has three other carbons attached to it |
| alcohols and phenols have much higher boiling points than similar alkanes and alkyl halides because | the hydrogen in the OH group is positively charged and is attracted to the lone pair of electrons on the negatively polarized oxygen atom of another molecule |
| the strucure around O of the alcohol or phenol is similar to that in water, being that it is | sp3 hybridized |
| the molecular forces that make the boiling points of alcohols and phenols higher are present and absent when? | present in solution(this accounts for the higher boiling point) but absent in the gas phase |
| The oxygen lone pair in the OH group of alcohols and phenols can act as a | Lewis Base and may be protonated by strong acids to yield oxonium ions, ROH2+ |
| Alcohols can also be acidic by | they can transfer a proton to water to a very small extent, and this creates a Hydrogen bonding network. Thus, alcohols are quite soluble in protic solvents. They can also react with bases, creating H30+ and an alkoxide ion RO-; or a phenoxide ion ArO- |
| The electron donating substituents that activate the ring toward electrophilic substitution also | increase the pKa of phenols |
| The electron withdrawing substituents that deactivate the ring | decrease the pKa of phenols |
| electron withdrawing groups are acid ___ | strengthening |
| electron donating groups are acid ___ | weakening |
| solvation and proton transfer can be affected by | steric effects |
| the more easy an alkoxide ion is solvated, the | more its formation is energetically favored |
| Phenols are much more acidic than alcohols due to | resonance stabilization of the phenoxide ion. Phenols react with NaOH solutions (but alcohols do not), forming salts that are soluble in dilute aqueous solution. |
| A phenolic compound can be separated from an organic solution by | extraction into basic aqueous solution and is isolated after acid is added to the solution |
| Phenols with nitro groups at the ortho and para positions are much stronger acids because | of the resonance stabilization of the alkoxide anion. |
| What other groups besides nitro can stabilize the alkoxide anion? | -SO3R & -CO2R |
| hydration: | regiospecific(limited) but not stereospecific |
| hydroboration/oxidation: | syn, non-Markovnikov hydration |
| oxymercuration/reduction: | Markovnikov hydration |
| Reduction of a carbonyl compound generally yields: | an alcohol |
| reduction of aldehydes gives | primary alcohols |
| reduction of ketones gives | secondary alcohols |
| NaBH4 is not | sensitive to moisture and does not reduce other common functional groups. Adds the equivalent of "H" |
| LiAlH4 is | more powerful than NaBH4, less specific, and very reactive with water. Adds the equivalent of "H" |
| Carboxylic acids and esters are reduced using LiAlH4 to give | primary alcohols(NaBH4 is not effective) |
| Alkyl, aryl, and vinylic halides react with Mg in ether or tetrahydrofuran to generate | Grignard Reagents. These Grignard reagents in turn react with carbonyl compounds to yield alcohols |
| Grignard Reagents act as | nucleophilic carbanions in adding to the carbonyl group. The intermediate alkoxide is then protonated to produce the alcohol |
| to produce only an aldehyde, milder oxidizing agents must be used (PCC, C5H6NCrO3Cl) pyridium chlorochromate in dichloromethane bc | other stronger oxidizing agents will oxidize the intermediate aldehydes into carboxylic acids |
| oxidizing agents used by chemists, such as chromate and permanganate salts are not | present in living systems |
| oxidation of a secondary alcohol produces | a ketone as the product |
| PCC is used to oxidize | sensitive secondary alcohols at low temperatures |
| Swern Oxidiztion is carried out in | DMSO not an Aqueous solvent,so the product stops at the aldehyde. also, the reaction does not involve chromium-based reagents which are toxic |
| tertiary alcohols react with HCl or HBr by | SN1 through carbocation intermediate to form alkyl halides |
| primary and secondary alcohols are converted into halides by treatment with | SOCl2 or PBr3 via SN2 mechanism |
| Reacting an alcohol with p-toluenesulfonyl chloride (tosyl chloride, p-TsCl)in pyridine yields | alkyl tosylates, ROTs. The formation of the tosylate does not involve the C–O bond so configuration at a chirality center is maintained. Alkyl tosylates react like alkyl halides, i.e. good leaving groups. |
| The SN2 reaction of an alcohol via a tosylate produces | an inversion at the chirality center. |
| The SN2 reaction of an alcohol via a halide proceeds with | two inversions, giving the product the same arrangement as the starting alcohol |
| an alkene can be formed from an alcohol by | a dehydration reaction to create a pi bond. specific reagents are needed to facilitate this elimination (usually strong acid) |
| tertiary alcohols are readily | dehydrated with acid |
| secondary alcohols require what for dehydration? | severe conditions (75% H2SO4, 100C) and sensitive molecules dont survive |
| primary alcohols require what for dehydration? | very harsh conditions; they are impractical and usually rearrange to form a more stable carbocation. reactivity is the resul of the nature of the carbocation intermediate |
| Phosphorus oxychloride in the amine solvent pyridine can lead to | dehydration of secondary and tertiary alcohols at low temperatures. This reaction proceeds via an E2 mechanism from an intermediate ester of POCl2 |
| hydroxyl groups can easily | transfer their proton to a basic reagent |
| Converting the hydroxyl to a (eventually removable) functional group without an acidic proton | protects the alcohol |
| Reaction with chlorotrimethylsilane in the presence of base yields | an unreactive trimethylsilyl (TMS) ether. The ether can be cleaved with acid or with fluoride ion to regenerate the alcohol. |
| The hydroxyl group of phenols is strongly activating, making phenols | good substrates for electrophilic halogenation, nitration, sulfonation, and Friedel–Crafts reactions (or any electrophilic substitution). |
| Reaction of a phenol with a strong oxidizing agent will yield | a quinone |
| Fremy's salt [(KSO3 )2 NO] works under mild conditions through | a radical mechanism |
| Ubiquinones mediate electron-transfer processes involved in energy production through | their redux reactions |
| Ether | has two organic groups (alkyl, aryl or vinyl) bonded to the same oxygen atom R-O-R' |
| diethyl ether can be prepared by | sulfuric acid catalyzed dehydration of ethanol or other primary alcohols. This is a good way to prepare symmetrical ethers |
| Williamson Ether Synthesis | reaction of metal alkoxides and primary alkyl halides and tosylates. Best method for the preparation of ethers.Best way to prepare unsymmetrical ethers, but is a good way to prepare symmetrical ethers too |
| Alkoxides made by reacting an alcohol with | a strong base like NaH |
| Reaction of alcohols with Ag2O directly with alkyl halide forms | ether in one step. Glucose reacts with excess iodomethane in the presence of Ag2O to generate a pentaether in 85% yield |
| Alkoxymercuration of Alkenes | react alkene with an alcohol and mercuric acetate or trifluoroacetate. demercuration with NaBH4 yields an ether. overall Markovnikov addition of alcohol to alkene. |
| Mechanicallistically, the alkoxymercuration of alkenes is analagous to | the hydration of an alkene |
| reactions of ethers: acidic cleavage | ethers are generally unreactive. strong acid will cleave an ether at elevated temperature. HI, HBr produce an alkyl halide from less hindered component by SN2(tertiary ethers undergo SN1) |
| The protonated ether can undergo substitution reactions because | a good leaving group (ROH) has been generated. |
| The neutral ether is unreactive because | it has a very poor leaving group (RO-) |
| chemically inert ethers are commonly used as organic solvents because | they can dissolve both polar and non-polar organics and because they are unreactive with most reagents except strong acids. |
| autoxidation is an unwanted side reaction that makes the handling of some ethers potentially dangerous due to | the formation of explosive hydroperoxides |
| Cleavage of Ethers by HX: primary and methyl ethers | cleavage occurs by an SN2 mechanism. Initial attack occurs on the less hindered carbon. The alcohol formed in the first step of the reaction will react further with HX. reaction is slow and requires high temperatures and concentrated acids |
| Cleavage of secondary, tertiary, allylic and benzylic ethers | The cleavage occurs by an SN1 mechanism with formation of the more stable carbocation. the reaction occurs at lower temperatures so the alcohol formed during the first step may not react further. E1 elimination will complete the substitution process. |
| Autoxidation of ethers | Autoxidation is a particular problem for 2° ethers but also occurs with common laboratory solvents such as diethyl ether and THF. |
| Reactions of ethers: claisen rearrangement | specific to allyl aryl ethers, ArOCH2CH=CH2. heating to 200-250C leads to an o-allylphenol. result is alkylation of the phenol in an ortho position |
| Cyclic ethers behave like acyclic ethers except if | the ring is 3-membered |
| dioxane and tetrahydrofuran are used as | solvents |
| Cyclic ethers: epoxides (oxiranes) | three membered ring ether is called an oxirane or an epoxide. |
| ethylene oxide is industrially important as an intermediate fro several processes. it is prepared by | a reaction of ethylene with oxygen at 300C and silver oxide catalyst |
| reactions of cyclic ethers | 5 and 6 membered rings such as THF and THP are as unreactive as their acyclic analogues. |
| 3 membered rings are uniquely reactive, much like cyclopropanes are much more reactive than ordinary alkanes. the reason for the reactivity is the same in both cases: | Any reaction that cleaves the ring releases about 25 kcal/mol of bond strain. This can make otherwise endergonic reactions thermodynamically feasible; can speedup the rate of reactions |
| the release of strain energy makes an epoxide | much more reactive than an acyclic ether |
| Epoxides from halohydrins | Addition of HO-X to an alkene gives a halohydrin. Treatment of a halohydrin with base gives an epoxide via intermolecular willamson ether synthesis. The nucleophile and leaving group muct be able to be anti |
| Preparation of Epoxides using a Peroxyacid | treat an alkene with a peroxyacid, mCPBA is the most common |
| Reactions of epoxides: acid catalyzed Ring-opening | water adds to epoxides with dilute acid at room temperature to give a 1,2-diol. Mechanism: acid protonates oxygen and water adds to the opposite side(trans addition) |
| halohydrins from epoxides | anhydrous HF,HBr, HCl, or HI combines with an epoxide and gives a trans product |
| regiochemistry of acid-catalyzed opening of epoxides | Nucleophile preferably adds to less hindered site if primary and secondary C’s. Beware however, if there is a tertiary center the ring will open to generate the tertiary carbocation and the nucleophile will add there. |
| rapid acid catalyzed ring cleavage of epoxides | The stereoselectivity is consistent with an ordinary SN 2 reaction, but the regiochemistry is not. |
| the transition state for an epoxide opening | The transition state for the reaction has an unbalanced structure with bond cleavage ahead of bond formation. |
| nucleophilic addition (and ring opening) TO EPOXIDES | Epoxides are subject to SN 2 reactions under conditions in which other ethers are inert. The attack occurs at the less hindered carbon and with inversion of configuration at the reacting carbon. |
| base catlayzed epoxide opening: SN2 | strain of the three membered ring is relieved on ring opening. hydroxide cleaves epoxides at elevated temperatures to give trans 1,2-diols |
| organometallic addition to epoxides | reactions with nucleophilic organo metallics RLi and RMgX are important C-C bond forming reactions. The configuration of the carbon that does not react remains unchanged |
| epoxides in biological systems: arene oxides | arene oxides are subject to two different reactions, the first is the nucleophilic attack like other epoxides and the second is a rearrangement via the NIH shift to make phenols |
| chemical carcinogens are electrophiles that react with | nucleophilic sites on the DNA bases, particularly deoxyguanosine |
| crown ethers | specifically bind certain metal ions or organic molecules to form a host-guest complex, an example of molecular recognition. |
| crown ethers can serve as phase-transfer catalysts by bringing ionic salts into non-polar solvents that they | are not normally soluble in. The anions that are brought into solution are very weakly solvated. these weakly solvated anions may react at an increased rate in these solvents as nucleophiles, redox reagents etc. |
| thiols are sulfure analogs of alcohols | thiols (RSH) named with the suffix thiol. SH group is called a mercapto group |
| although they have similar chemistry to alcohols, thiols have unique properties that are distinct from alcohols | In protic solvents RS- are better nucleophiles than the corresponding RO- because they are less heavily solvated. |
| RSH2+ are not usually used as substrates in substitution reactions because | H2S is not as good a leaving group as H2O and RSH is more difficult to protonate. |
| thiols: formation and reaction | From alkyl halides by displacement with a sulfur nucleophile such as –SH or S-2 . The alkylthiol product can undergo further reaction with the alkyl halide to give a symmetrical sulfide, giving a poorer yield of the thiol. |
| thiols: formation and reaction 2 | Thioamides may be hydrolyzed to yield thiols, but very slow and relatively basic conditions are necessary. |
| using thiourea to form alkylthiols | Thiols can undergo further reaction with the alkyl halide to give dialkyl sulfides. For a pure alkylthiol use thiourea (NH2 (C=S)NH2 ) as the nucleophile. |
| using thiourea to form alkylthiols 2 | This gives an intermediate alkylisothiourea salt, which is hydrolyzed cleanly to the alkyl thiourea. |
| oxidation of thiols to disulfates | Reaction of an alkyl thiol (RSH) with bromine or iodine gives a disulfide (RSSR). The thiol is oxidized in the process and the halogen is reduced. |
| sulfides | Thiolates (RS- ) are formed by the reaction of a thiol with a base. Thiolates react with primary or secondary alkyl halide to give sulfides (RSR’). Thiolates are excellent nucleophiles and react with many electrophiles. |
| More on the Synthesis of Thioethers (Sulfides). | Reaction is analogous to the Williamson ether synthesis. Since RS- is a relatively weak base it is less likely to cause elimination reactions than is RO- . R' should still be as unhindered as possible. |
| The thioether is far more | nucleophilic than an ether is |
| Sulfur compounds are more nucleophilic than their oxygen-compound analogs. | The 3p electrons valence electrons (on S) are less tightly held than 2p electrons (on O). Sulfides react with primary alkyl halides (SN 2) to give trialkylsulfonium salts (R3 S+ ) |
| oxidation reactions of sulfides/thioethers | Sulfides are easily oxidized with H2O2 to the sulfoxide (R2 SO). Oxidation of a sulfoxide with a peroxyacid yields a sulfone (R2 SO2 ). Dimethyl sulfoxide (DMSO) is often used as a polar aprotic solvent. |
| Aldehydes and Ketones | Aldehydes (RCHO) and ketones (R2 CO) are characterized by the the carbonyl functional group (C=O) The compounds occur widely in nature as intermediates in metabolism and biosynthesis |
| Class I carbonyl compounds | Class I carbonyl compounds have groups that can be replaced by a nucleophile. A carbonyl group has a C=O. An acyl group is an alkyl or aryl group attached to the carbonyl group. |
| Class I carbonyl compounds 2 | The group attached to the carbonyl group strongly affects the reactivity of the carbonyl compound. |
| Class I carbonyl compounds 3 | carboxylic acid (O=COH), ester(OR), acid anhydride(O[C=O]R), acyl halides(O=CX), amides(NH2, NHR, NR2) |
| Class II carbonyl compounds | s have groups that cannot be replaced by a nucleophile. These are commonly aldehydes and ketones. The H bonded to the acyl group of an aldehyde or the R group bonded to the acyl group of a ketone cannot be readily replaced by a nucleophile. |
| structure of a carbonyl carbon | the carbonyl carbon in carboxylic acids and carboxylic acid derivatives is sp2 hybridized, has bond angles of 120 and has a trigonal planar shape |
| naming aldehydes and ketones | Aldehydes are named by replacing the terminal -e of the corresponding alkane name with –al The parent chain must contain the ⎯CHO group The ⎯CHO carbon is numbered as C1 If the ⎯CHO group is attached to a ring, use the suffix carbaldehyde. |
| Naming Ketones | Replace the terminal -e of the alkane name with –one Parent chain is the longest one that contains the ketone group Numbering begins at the end nearer the carbonyl carbon |
| ketones and aldehydes as substituents | The R–C=O as a substituent is an acyl group, used with the suffix -yl from the root of the carboxylic acid CH3 CO: acetyl; CHO: formyl; C6 H5 CO: benzoyl |
| ketones and aldehydes as substituents 2 | The prefix oxo- is used if other functional groups are present and the doubly bonded oxygen is labeled as a substituent on a parent chain |
| Preparation of aldehydes and ketones | Oxidize primary alcohols using pyridinium chlorochromate Ozonolysis of alkenes with a vinylic hydrogen Reduce esters with diisobutylaluminum hydride (DIBAH) |
| preparing ketones | Oxidize a 2° alcohol Many reagents possible: choose for the specific situation (scale, cost, and acid/base sensitivity |
| Ketones from ozonolysis | Ozonolysis of alkenes yields ketones if one of the unsaturated carbon atoms is disubstitute |
| Aryl ketones by acylation | Friedel–Crafts acylation of an aromatic ring with an acid chloride in the presence of AlCl3 catalyst |
| Methyl ketones by hydrating alkynes | Hydration of terminal alkynes in the presence of Hg 2 |
| oxidation of aldehydes and ketones | CrO3 in aqueous acid oxidizes aldehydes to carboxylic acids efficiently. Silver oxide, Ag2O, in aqueous ammonia (Tollens’ reagent) oxidizes aldehydes (no |
| ketones oxidize with difficulty | Undergo slow cleavage with hot, alkaline KMnO4 C–C bond next to C=O is broken to give carboxylic acids Reaction is practical for cleaving symmetrical ketones |
| nucleophilic addition reactions of aldehydes and ketones | A nucleophile attacks the positively charged carbonyl carbon producing a ionic tetrahedral intermediate. This addition can be either acid or base catalyzed. |
| Relative Reactivity of Aldehydes and Ketones | Aldehydes are generally more reactive than ketones in nucleophilic addition reactions. Nu - approaches 75° to the plane of C=O and adds to the carbonyl carbon |
| Relative Reactivity of Aldehydes and Ketones 2 | The transition state for addition is less crowded and lower in energy for an aldehyde (a) than for a ketone (b). Aldehydes have one large substituent bonded to the C=O: ketones have two. |
| Electrophilicity of Aldehydes and Ketones | Aldehyde C=O is more polarized than ketone C=O. As in carbocations, more alkyl groups stabilize positive character. Ketone has more alkyl groups, stabilizing the C=O carbon inductive |
| Reactivity of Aromatic aldehydes | Less reactive in nucleophilic addition reactions than aliphatic aldehydes. Electron-donating resonance effect of aromatic ring makes C=O less reactive electrophile than the carbonyl group of an aliphatic aldehyde. |
| Nucleophilic Addition of H2O: Hydration | Aldehydes and ketones react with water to yield 1,1-diols (geminal (gem) diols). Hyrdation is reversible: a gem diol can eliminate water |
| hydration of aldehydes | Aldehyde oxidations occur through 1,1-diols (“hydrates”). Reversible addition of water to the carbonyl group. Addition of water is catalyzed by both acid and base. Aldehyde hydrate is oxidized to a carboxylic acid by usual reagents for alcohols |
| Base-Catalyzed Addition of Water | The base-catalyzed hydration nucleophile is the hydroxide ion, which is a much stronger nucleophile than water. |
| Acid-Catalyzed Addition of Water | The first step is the protonation of C=O, this makes it more electrophilic |
| Addition of H-Y to C=O | Reaction of C=O with H-Y, where Y is electronegative, gives an addition product (“adduct”). Formation is readily reversible |
| Nucleophilic Addition of HCN: Cyanohydrin Formation | Aldehydes and unhindered ketones react with HCN to yield cyanohydrins, RCH(OH)C≡N. Addition of HCN is reversible and base-catalyzed, generating nucleophilic cyanide ion, CN- . |
| Nucleophilic Addition of HCN: Cyanohydrin Formation 2 | Addition of CN- to C=O yields a tetrahedral intermediate, which is then protonated. Equilibrium favors adduct. |
| Uses of Cyanohydrins | The nitrile group (⎯C≡N) can be reduced with LiAlH4 to yield a primary amine (RCH2 NH2 ). Can be hydrolyzed by hot acid to yield a carboxylic acid |
| Nucleophilic Addition of Grignard Reagents and Hydride Reagents: Alcohol Formation | Treatment of aldehydes or ketones with Grignard reagents yields an alcohol. Nucleophilic addition of the equivalent of a carbon anion, or carbanion. |
| Nucleophilic Addition of Grignard Reagents and Hydride Reagents: Alcohol Formation 2 | . A carbon–magnesium bond is strongly polarized, so a Grignard reagent reacts for all practical purposes as R: - MgX+ |
| Mechanism of Addition of Grignard Reagents | Complexation of C=O by Mg 2+, Nucleophilic addition of R: - , protonation by dilute acid yields the neutral alcohol. Grignard additions are irreversible because a carbanion is not a leaving group |
| Hydride Addition | Convert C=O to CH-OH. LiAlH4 and NaBH4 react as hydride ion donors to the electrophilic carbonyl carbon. Subsequent protonation of the oxygen anion of the tetrahedral intermediate after addition yields the alcohol |
| Nucleophilic Addition of Amines: Imine and Enamine Formation | RNH2 adds to C=O to form imines, R2 C=NR (after loss of HOH) R2 NH yields enamines, R2 N⎯CR=CR2 (after loss of HOH) (ene + amine = unsaturated amine) |
| Mechanism of Formation of Imines | Primary amine adds to C=O. Proton is lost from N and adds to O to yield a neutral amino alcohol (carbinolamine). Protonation of OH converts into water as the leaving group. Result is iminium ion, which loses proton. |
| Mechanism of Formation of Imines 2 | Acid is required for loss of OH – too much acid blocks RNH2 |
| Imine Derivatives | Addition of amines with an atom containing a lone pair of electrons on the adjacent atom occurs very readily, giving useful, stable imines. For example, hydroxylamine forms oximes and 2,4-dinitrophenylhydrazine |
| Imine Derivatives 2 | readily forms 2,4- dinitrophenylhydrazones. These are usually solids and help in characterizing liquid ketones or aldehydes by melting points. |
| Enamine Formation | For enamine formation on the α-carbon there must a hydrogen present in order for elimination to occur. After addition of R2 NH, proton is lost from adjacent carbon |
| Nucleophilic Addition of Hydrazine: The Wolff–Kishner Reaction | Treatment of an aldehyde or ketone with hydrazine, H2 NNH2 and KOH converts the compound to an alkane. Originally carried out at high temperatures but with dimethyl sulfoxide as solvent takes place near room temperature. |
| Nucleophilic Addition of Alcohols: Acetal Formation | Alcohols are weak nucleophiles but acid promotes addition forming the conjugate acid of C=O. Addition yields a hydroxy ether, called a hemiacetal (reversible); further reaction can occur |
| Nucleophilic Addition of Alcohols: Acetal Formation 2 | Protonation of the ⎯OH and loss of water leads to an oxonium ion, R2 C=OR+ to which a second alcohol adds to form the acetal |
| Uses of Acetals | Acetals can serve as protecting groups for aldehydes and ketones. It is convenient to use a diol, to form a cyclic acetal (the reaction goes even more readily) |
| Nucleophilic Addition of Phosphorus Ylides: The Wittig Reaction | The sequence converts C=O is to C=C. A phosphorus ylide adds to an aldehyde or ketone to yield a dipolar intermediate called a betaine. The intermediate spontaneously decomposes through a four-membered ring |
| Nucleophilic Addition of Phosphorus Ylides: The Wittig Reaction 2 | to yield alkene and triphenylphosphine oxide, (Ph)3 P=O. Formation of the ylide is shown above, it must be formed from a 1° or 2° alkyl halide or tosylate |
| Uses of the Wittig Reaction | Can be used for monosubstituted, disubstituted, and trisubstituted alkenes but not tetrasubstituted alkenes. The reaction yields a pure alkene of known structure. |
| The Cannizaro Reaction | The adduct of an aldehyde and OH- can transfer hydride ion to another aldehyde C=O resulting in a simultaneous oxidation and reduction (disproportionation) |
| Conjugate Nucleophilic Addition to α,β-Unsaturated Aldehydes and Ketones | A nucleophile can add to the C=C double bond of an α,β-unsaturated aldehyde or ketone (conjugate addition, or 1,4 addition. The initial product is a resonance-stabilized enolate ion, which is then protonated |
| Conjugate Addition of Amine | Primary and secondary amines add to α,β-unsaturated aldehydes and ketones to yield β-amino aldehydes and ketones |
| Conjugate Addition of Alkyl Groups: Organocopper Reactions | Reaction of an α, β-unsaturated ketone with a lithium diorganocopper reagent. Diorganocopper (Gilman) reagents form by reaction of 1 equivalent of cuprous iodide and 2 equivalents |
| Conjugate Addition of Alkyl Groups: Organocopper Reactions 2 | of organolithium. 1°, 2°, 3° alkyl, aryl and alkenyl groups react but not alkynyl groups. |
| Mechanism of Alkyl Conjugate Addition | Conjugate nucleophilic addition of a diorganocopper anion, R2 Cu - , to an enone. Transfer of an R group and elimination of a neutral organocopper species, RCu |
Created by:
ESPOLADE
Popular Chemistry sets