Química Orgânica 2 · Carbonyl chemistry
Adições à carbonila: revisão para a prova: problemas de prática
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- Conjugate addition of lithium dimethylcuprate to cyclohex-2-en-1-one
- Base-catalysed cyanohydrin formation from pentanal
- Ethylene ketal of butan-2-one
- Pyrrolidine enamine of cyclopentanone
- Ethylmagnesium bromide adds to propanal
- Acid-catalysed cyclic hemiacetal from 5-hydroxypentanal
- N-Methylimine from pentan-3-one
- LiAlH4 reduction of heptan-4-one
- Methyllithium adds 1,2 to cyclohex-2-en-1-one
Desenhe o mecanismo 40
- Conjugate addition of lithium dimethylcuprate to cyclohex-2-en-1-oneDraw the 1,4-addition of a methyl group from lithium dimethylcuprate to the β-carbon of cyclohex-2-en-1-one and the protonation of the enolate at carbon, giving 3-methylcyclohexan-1-one.
- Base-catalysed cyanohydrin formation from pentanalDraw the addition of cyanide to pentanal and the proton transfer from HCN that gives 2-hydroxyhexanenitrile and regenerates cyanide.
- Ethylene ketal of butan-2-oneDraw the acid-catalysed formation of 2-ethyl-2-methyl-1,3-dioxolane from butan-2-one and ethane-1,2-diol, using TsOH and tosylate for every proton transfer, and explain why water is removed.
- Pyrrolidine enamine of cyclopentanoneDraw the acid-catalysed condensation of cyclopentanone with the secondary amine pyrrolidine through a carbinolamine and an iminium ion to the enamine, and explain why an enamine rather than an imine forms.
- Ethylmagnesium bromide adds to propanalDraw the addition of ethylmagnesium bromide to propanal and the acidic workup that gives pentan-3-ol.
- Acid-catalysed cyclic hemiacetal from 5-hydroxypentanalDraw the acid-catalysed intramolecular addition of the hydroxyl group of 5-hydroxypentanal to its aldehyde, giving the six-membered cyclic hemiacetal oxan-2-ol.
- N-Methylimine from pentan-3-oneDraw imine formation from pentan-3-one and methylamine with acetic acid and acetate as the only proton donor and acceptor, and explain why the reaction is run near pH 4–5.
- LiAlH4 reduction of heptan-4-oneDraw hydride transfer from aluminohydride to heptan-4-one in dry ether and protonation of the alkoxide by water in the workup, giving heptan-4-ol.
- Methyllithium adds 1,2 to cyclohex-2-en-1-oneDraw the direct (1,2) addition of methyllithium to cyclohex-2-en-1-one and the mild NH4Cl workup that gives 1-methylcyclohex-2-en-1-ol.
- Two equivalents of methylmagnesium bromide add to ethyl benzoateDraw the addition of methylmagnesium bromide to ethyl benzoate, the loss of ethoxide to give acetophenone, the second addition, and the acidic workup to 2-phenylpropan-2-ol.
- NaBH4 reduction of 3-methylbutanalDraw hydride transfer from borohydride to the aldehyde carbon of 3-methylbutanal and protonation of the alkoxide by ethanol, giving 3-methylbutan-1-ol.
- Phenyllithium adds to 2-methylpropanalDraw the addition of phenyllithium to 2-methylpropanal and the separate acidic workup that gives 2-methyl-1-phenylpropan-1-ol, and explain why the addition must be run dry.
- Base-catalysed conjugate addition of ethanethiol to cyclopent-2-en-1-oneDraw the conjugate addition of ethanethiolate to cyclopent-2-en-1-one and the protonation of the enolate at carbon by ethanethiol, which regenerates the thiolate.
- Wittig methylenation of benzophenoneDraw the formation of the oxaphosphetane from methylenetriphenylphosphorane and benzophenone and its collapse to 1,1-diphenylethene and triphenylphosphine oxide.
- Wittig synthesis of propylidenecyclopentane from 1-bromopropaneDraw the SN2 formation of propyltriphenylphosphonium bromide, its deprotonation by butyllithium to the ylide, and the Wittig reaction with cyclopentanone that gives propylidenecyclopentane and triphenylphosphine oxide.
- Adição aza-Michael: 3-(dietilamino)propanoato de metilaDesenhe a adição 1,4 da dietilamina ao acrilato de metila, a protonação do enolato no carbono pelo metanol e a perda do próton N–H, formando o 3-(dietilamino)propanoato de metila.
- Adição 1,4 de dibutilcuprato: 4-metiloctan-2-onaDesenhe a adição 1,4 de um grupo butila do dibutilcuprato de lítio ao carbono β da (E)-pent-3-en-2-ona e a protonação do enolato no carbono que forma a 4-metiloctan-2-ona.
- Conjugate addition of cyanide to chalconeDraw cyanide adding to the β-carbon of chalcone and protonation of the enolate at carbon to give 4-oxo-2,4-diphenylbutanenitrile.
- Cyanohydrin of cyclohexanoneDraw cyanide adding to cyclohexanone and HCN protonating the alkoxide to give 1-hydroxycyclohexane-1-carbonitrile.
- Cianoidrina da ciclopentanona: 1-hidroxiciclopentano-1-carbonitrilaDesenhe a adição de cianeto à ciclopentanona e a protonação do alcóxido pelo HCN a 1-hidroxiciclopentano-1-carbonitrila, regenerando o cianeto catalisador.
- DIBAL-H reduction of ethyl benzoate to benzaldehydeDraw DIBAL-H coordinating to ethyl benzoate, hydride delivery to the stable tetrahedral intermediate, and the acidic workup that releases benzaldehyde.
- Dimethyl ketal of cyclohexanoneDraw the acid-catalysed formation of 1,1-dimethoxycyclohexane from cyclohexanone through the hemiketal and the oxocarbenium ion.
- Acetal cíclico do benzaldeído: 2-fenil-1,3-dioxanoDesenhe a condensação do benzaldeído com propano-1,3-diol catalisada por TsOH, passando pelo hemiacetal e pelo íon oxocarbênio, até o acetal cíclico 2-fenil-1,3-dioxano.
- Enamina de morfolina: 4-(ciclo-hex-1-en-1-il)morfolinaDesenhe a condensação da ciclo-hexanona com a amina secundária morfolina catalisada por TsOH, passando por uma carbinolamina e um íon imínio, até a 4-(ciclo-hex-1-en-1-il)morfolina.
- Dois EtMgBr abrem a γ-butirolactona: 4-etil-hexano-1,4-diolDesenhe a adição do brometo de etilmagnésio à γ-butirolactona, a abertura do anel a um cetoalcóxido, a segunda adição à cetona e o tratamento com NH4Cl que leva ao 4-etil-hexano-1,4-diol.
- Butylmagnesium bromide opens ethylene oxide: hexan-1-olDraw butylmagnesium bromide opening ethylene oxide by SN2 and the acidic workup to hexan-1-ol.
- Hidratação da hexafluoroacetona a hexafluoropropano-2,2-diolDesenhe a adição de água à hexafluoroacetona e as transferências de próton mediadas pela água que formam o diol geminal hexafluoropropano-2,2-diol, e explique por que esse hidrato é favorecido.
- Imine from cyclohexanone and anilineDraw the acid-catalysed addition of aniline to cyclohexanone, proton transfers to the carbinolamine, loss of water and deprotonation to N-cyclohexylideneaniline.
- Redução do ciclopentanocarbaldeído com LiAlH4 a ciclopentilmetanolDesenhe a adição de hidreto do LiAlH4 ao ciclopentanocarbaldeído e o tratamento ácido que protona o alcóxido a ciclopentilmetanol.
- Redução de Luche: 3-metilciclo-hex-2-en-1-ol a partir da enonaDesenhe a adição 1,2 de hidreto de um metoxiboroidreto à 3-metilciclo-hex-2-en-1-ona em condições de Luche e a protonação pelo metanol que forma o álcool alílico 3-metilciclo-hex-2-en-1-ol.
- Metil-lítio e ciclo-hexanocarbaldeído: 1-ciclo-hexiletan-1-olDesenhe a adição do grupo metila do metil-lítio ao ciclo-hexanocarbaldeído e o tratamento com NH4Cl que forma o álcool secundário 1-ciclo-hexiletan-1-ol.
- NaBH4 reduction of cyclohex-2-enone to cyclohex-2-en-1-olDraw 1,2-hydride delivery from borohydride to cyclohex-2-enone and protonation of the alkoxide by methanol to give cyclohex-2-en-1-ol.
- Formação de oxima: (E)-acetofenona oxima a partir de hidroxilaminaDesenhe a condensação da hidroxilamina com a acetofenona catalisada por ácido acético, passando pela carbinolamina até a (E)-acetofenona oxima, com o tampão de acetato atuando como ácido e como base.
- Benzaldehyde phenylhydrazoneDraw acid-catalysed addition of phenylhydrazine to benzaldehyde, proton transfers, loss of water and deprotonation to benzaldehyde phenylhydrazone.
- Brometo de vinilmagnésio e benzaldeído: 1-fenilprop-2-en-1-olDesenhe a adição do brometo de vinilmagnésio ao benzaldeído e o tratamento com cloreto de amônio que fornece o álcool alílico 1-fenilprop-2-en-1-ol.
- Wittig reaction of acetophenone: 2-phenylbut-2-eneDraw ethylidenetriphenylphosphorane adding to acetophenone, oxaphosphetane formation and collapse to 2-phenylbut-2-ene.
- Wittig com ciclopentanona: propan-2-ilidenociclopentanoDesenhe a adição do isopropilidenotrifenilfosforano à ciclopentanona, o fechamento do anel até o oxafosfetano e seu colapso ao alceno tetrassubstituído propan-2-ilidenociclopentano.
- Ilídeo estabilizado e butanal: (E)-hept-2-enoato de etilaDesenhe a adição do ilídeo estabilizado por éster (trifenilfosforanilideno)acetato de etila ao butanal, o fechamento do anel até o oxafosfetano e seu colapso ao (E)-hept-2-enoato de etila, e explique a seletividade E.
- Wittig synthesis of (E)-stilbene from benzaldehydeDraw benzylidenetriphenylphosphorane adding to benzaldehyde, ring closure to the oxaphosphetane and its collapse to (E)-stilbene (benzaldehyde).
- Wittig Z-seletiva: benzaldeído a (Z)-1-fenilbut-1-enoDesenhe o propilidenotrifenilfosforano e o benzaldeído formando o oxafosfetano e seu colapso ao (Z)-1-fenilbut-1-eno, e explique por que o ilídeo não estabilizado fornece o alceno Z.
Preveja o produto 13
- Cuprate meets mesityl oxidePredict the conjugate-addition product of a cuprate with a β,β-disubstituted enone.
- Which enamine does 2-methylcyclohexanone give?Predict the major regioisomer of the pyrrolidine enamine of an unsymmetrical cyclic ketone from allylic strain.
- Order the events of imine formationPut the elementary events of acid-catalysed imine formation from a primary amine in the order they occur.
- NaBH₄ with a keto esterPredict the chemoselectivity of NaBH₄ toward a molecule containing both a ketone and an ester.
- Phenyl Grignard and a ketonePredict the tertiary alcohol formed when an aryl Grignard reagent adds to a ketone.
- Geometry from a stabilised ylidePredict the alkene geometry formed by a stabilised Wittig reagent with an aldehyde.
- Trap the cuprate enolatePredict the product of conjugate addition followed by alkylation of the enolate formed regiospecifically in that addition.
- Methylenation of a cyclohexanonePredict the alkene formed by Wittig methylenation of a ketone and distinguish it from Grignard-type and sulfur-ylide products.
- Formate ester plus two GrignardsPredict the secondary alcohol formed when a formate ester reacts with two equivalents of a Grignard reagent.
- What survives the workup?Predict the isolated product after cuprate conjugate addition and aqueous workup.
- Hidrólise da cianidrina do benzaldeídoPreveja que a hidrólise ácida converte a nitrila de uma cianidrina em ácido carboxílico enquanto o OH permanece, fornecendo um α-hidroxiácido.
- Which conditions hydrolyze an imine?Choose the conditions that convert an imine back to its carbonyl compound and amine.
- Stabilised ylide geometryPredict the alkene geometry from a Wittig reaction with a stabilised ylide.
Classificar 6
- Spot the hemiacetalClassify carbonyl addition products as hemiacetal, acetal, hydrate or none from the groups on a single carbon.
- Find the conjugate acceptorIdentify a Michael acceptor by checking whether the C=C is conjugated with a carbonyl group.
- Spot the ketalRecognise a ketal by its carbon bearing two ether oxygens and no OH.
- Which reagents add 1,4?Sort nucleophiles into those that add conjugately (1,4) to an enone.
- Which amine gives an enamine?Identify the amine class that forms an enamine with a ketone.
- Qual estrutura é a 4-metilpentan-2-ona?Converta o nome IUPAC 4-metilpentan-2-ona em estrutura: uma cadeia de cinco carbonos numerada a partir da extremidade mais próxima da C=O, com a cetona em C2 e uma metila em C4.
Comparar 3
- Rank carbonyl electrophilicityRank aldehydes and ketones by how readily they undergo nucleophilic addition, using hydration as the measure.
- Which ketone resists cyanohydrin formation?Compare the position of cyanohydrin equilibria for aldehydes and ketones from steric and conjugation effects.
- Rank the hydride reagentsOrder three common hydride reagents by their strength as hydride donors toward carbonyl groups.
Calcular 6
- How much ethanal is hydrated?Calculate the percentage of an aldehyde present as its hydrate from the hydration equilibrium constant.
- Grignard equivalents for a hydroxy ketoneCount the equivalents of Grignard reagent consumed by a substrate that carries both an acidic O–H and a ketone.
- How much NaBH₄ is needed?Calculate the theoretical minimum mass of NaBH₄ for a ketone reduction from the number of hydrides per borohydride.
- Atom economy of a Wittig reactionCalculate the atom economy of a Wittig methylenation and relate it to the triphenylphosphine oxide by-product.
- Hydride equivalents for a keto esterCount the hydride equivalents LiAlH4 delivers to a molecule with a ketone and an ester.
- Conte as rotas de Grignard para o 2-metilbutan-2-olConte os pares distintos de reagente de Grignard e composto carbonílico que constroem o álcool terciário 2-metilbutan-2-ol, incluindo a rota via éster que adiciona dois grupos iguais.
Encontre o erro 4
- Why did the LiAlH₄ reduction fail?Diagnose the failure of a LiAlH₄ reduction run in a protic solvent.
- Fix the route to 3,3-dimethylcyclohexanoneDiagnose a synthesis that uses an organolithium where a conjugate-addition reagent is needed.
- A Wittig reaction that stalledDiagnose a failed Wittig reaction caused by an acidic proton in the substrate.
- Diagnose a failed GrignardExplain why acid must be added only after the Grignard addition is complete.
Interprete as evidências 1
- Estiramento C=O no IV: pentan-2-ona ou butanoato de metila?Use a frequência de estiramento C=O para distinguir um éster saturado (cerca de 1735 cm⁻¹) de uma cetona saturada (cerca de 1715 cm⁻¹).
Trabalhe de trás para frente 3
- Which carbonyl partner for Et₃COH?Work back from a tertiary alcohol with three identical groups to the ester that gives it with excess Grignard reagent.
- Make ethylidenecyclopentaneChoose the carbonyl compound and ylide whose Wittig reaction gives a target exocyclic alkene, and reject a dehydration route that misplaces the C=C.
- Qual haleto forma o benzilidenotrifenilfosforano?Parta de um ilídeo de Wittig e volte ao haleto de alquila que forma seu sal de fosfônio por SN2 com trifenilfosfina.
Planeje uma síntese 2
- Reduce the ester, keep the ketonePlan a protecting-group sequence that reduces an ester in the presence of a more reactive ketone.
- Reduce the C=O but keep the C=CChoose reagents that reduce an enone carbonyl while leaving the conjugated alkene intact.
Explique por quê 2
- Why are acetals good protecting groups?Explain why acetals survive basic and nucleophilic reagents but are hydrolysed by aqueous acid.
- Why does the conjugate adduct win?Explain why reversible nucleophiles give conjugate adducts of enones using bond strengths.
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