Química Orgânica 2 · Carbonyl and enolate chemistry
Enolatos: alquilação, condensações e adições conjugadas: problemas de prática
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Comece a desenhar: Enolatos: alquilação, condensações e adições conjugadas
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- Acetoacetic ester alkylation with allyl bromide
- Self-aldol condensation of butanal
- Decarboxylation of butylmalonic acid to hexanoic acid
- Crossed Claisen of cyclohexanone with diethyl oxalate
- Dieckmann cyclisation of diethyl heptanedioate
- Directed aldol of cyclohexanone with benzaldehyde
- Claisen condensation of ethyl propanoate
- Intramolecular aldol condensation of hexane-2,5-dione
- Kinetic enolate alkylation of 3-methylbutan-2-one with benzyl bromide
Desenhe o mecanismo 38
- Acetoacetic ester alkylation with allyl bromideDeprotonate ethyl acetoacetate with the matching alkoxide and alkylate the enolate on carbon with allyl bromide.
- Self-aldol condensation of butanalDraw the hydroxide-catalysed aldol addition of two butanal molecules and the E1cB dehydration that gives (E)-2-ethylhex-2-enal.
- Decarboxylation of butylmalonic acid to hexanoic acidDraw the cyclic loss of CO₂ from a substituted malonic acid and the acid-catalysed tautomerisation of the enol to hexanoic acid.
- Crossed Claisen of cyclohexanone with diethyl oxalateDraw the ethoxide-mediated acylation of cyclohexanone by diethyl oxalate, the deprotonation of the 1,3-dicarbonyl product that drives the reaction, and the acid workup.
- Dieckmann cyclisation of diethyl heptanedioateDraw the intramolecular Claisen (Dieckmann) condensation of diethyl heptanedioate to the six-membered cyclic β-keto ester, including the deprotonation that drives it and the acid workup.
- Directed aldol of cyclohexanone with benzaldehydePreform the cyclohexanone enolate with LDA, add it to benzaldehyde, and protonate the alkoxide at workup to give the β-hydroxy ketone.
- Claisen condensation of ethyl propanoateDraw the Claisen condensation of ethyl propanoate: enolate formation, addition to a second ester, loss of ethoxide, the deprotonation that drives the reaction, and acid workup.
- Intramolecular aldol condensation of hexane-2,5-dioneDraw the hydroxide-catalysed ring closure of hexane-2,5-dione onto its own second ketone and the E1cB dehydration that gives 3-methylcyclopent-2-en-1-one.
- Kinetic enolate alkylation of 3-methylbutan-2-one with benzyl bromideDraw the LDA deprotonation of 3-methylbutan-2-one at its methyl group and the SN2 benzylation of the kinetic enolate.
- Methylation of methyl phenylacetate through its LDA enolateForm an ester enolate quantitatively with LDA and alkylate it with iodomethane by an SN2 reaction.
- Malonic ester alkylation with 1-bromobutaneDeprotonate diethyl malonate with ethoxide, show how both ester groups share the negative charge, and alkylate the enolate with 1-bromobutane.
- Diethyl malonate and 1,4-dibromobutane close a cyclopentaneUse two successive malonate alkylations, the second one intramolecular, to build diethyl cyclopentane-1,1-dicarboxylate.
- Michael addition of pentane-2,4-dione to cyclohex-2-en-1-oneDraw the base-catalysed conjugate addition of the pentane-2,4-dione enolate to the β-carbon of cyclohex-2-en-1-one and the proton transfer that regenerates ethoxide.
- Michael addition of ethyl 2-oxocyclopentane-1-carboxylate to acrylonitrileDraw the conjugate addition of a cyclic β-keto ester enolate to acrylonitrile and the proton transfer that regenerates the ethoxide catalyst.
- Robinson annulation of 2-methylcyclohexanone with methyl vinyl ketoneDraw the Michael addition of the more substituted 2-methylcyclohexanone enolate to methyl vinyl ketone, the intramolecular aldol addition that closes a six-membered ring, and the E1cB dehydration to the bicyclic enone.
- 4-Fenilbutan-2-ona pela síntese do éster acetoacéticoDesenhe a síntese da 4-fenilbutan-2-ona pelo éster acetoacético: SN2 do enolato no brometo de benzila, hidrólise ácida do éster etílico, descarboxilação do β-cetoácido e tautomerização do enol.
- (E)-4-(Furan-2-il)but-3-en-2-ona a partir de furfural e acetonaDesenhe a condensação aldólica cruzada da acetona com furfural promovida por hidróxido: formação do enolato, adição ao aldeído, protonação e desidratação E1cB à (E)-4-(furan-2-il)but-3-en-2-ona.
- 1,1,1-Trifluoropentano-2,4-diona por Claisen cruzadaDesenhe a Claisen cruzada da acetona com trifluoroacetato de etila: adição do enolato, perda de etóxido, desprotonação da β-dicetona e tratamento ácido até a 1,1,1-trifluoropentano-2,4-diona.
- 2-Oxociclopentano-1-carbaldeído por Claisen cruzadaDesenhe a Claisen cruzada da ciclopentanona com formiato de etila promovida por etóxido: adição do enolato ao formiato, perda de etóxido, desprotonação do produto 1,3-dicarbonílico e tratamento ácido até o 2-oxociclopentano-1-carbaldeído.
- Descarboxilação do ácido 2-oxociclo-hexano-1-carboxílicoDesenhe a descarboxilação cíclica de seis átomos do ácido 2-oxociclo-hexano-1-carboxílico ao enol e CO2, e a tautomerização do ciclo-hex-1-en-1-ol a ciclo-hexanona mediada por ácido.
- Contração de anel de Favorskii da 2-clorociclo-heptanonaDesenhe o rearranjo de Favorskii da 2-clorociclo-heptanona com metóxido, do enolato α′, passando pela ciclopropanona bicíclica, até o ciclo-hexanocarboxilato de metila.
- Ciclo-hexanocarboxilato e bromofórmio pela reação do halofórmioDesenhe as três bromações do grupo metila da 1-ciclo-hexiletan-1-ona promovidas por hidróxido, a adição de hidróxido, a perda do ânion tribromometila e a transferência de próton que fornece ciclo-hexanocarboxilato e bromofórmio.
- α-Bromação HVZ do ácido 3-fenilpropanoicoDesenhe a sequência HVZ no ácido 3-fenilpropanoico: formação do brometo de acila com PBr3, enolização, α-bromação por Br2 e hidrólise a ácido 2-bromo-3-fenilpropanoico.
- 2-Bromobutanoic acid by the Hell–Volhard–Zelinsky reactionDraw the HVZ sequence on butanoic acid: conversion to the acyl bromide with PBr3, enolization, α-bromination by Br2 and hydrolysis to 2-bromobutanoic acid.
- 3-Methylcyclohex-2-en-1-one by intramolecular aldol condensation of heptane-2,6-dioneDraw the hydroxide-promoted ring closure of heptane-2,6-dione through its terminal-methyl enolate and the E1cB dehydration that gives 3-methylcyclohex-2-en-1-one.
- Condensação aldólica intramolecular da octano-2,7-dionaDesenhe o fechamento de anel da octano-2,7-diona promovido por hidróxido, via seu enolato interno em C3, e a desidratação E1cB que forma a 1-(2-metilciclopent-1-en-1-il)etan-1-ona.
- Propanoate and iodoform from butan-2-one (haloform reaction)Draw the base-promoted triple iodination of the methyl group of butan-2-one, hydroxide attack and loss of the triiodomethyl anion, and the proton transfer that gives propanoate and iodoform.
- 2-Allyl-6-methylcyclohexanone by kinetic enolate allylationDraw LDA deprotonation of 2-methylcyclohexanone at the less substituted α-carbon and SN2 allylation of that kinetic enolate by allyl bromide.
- Benzylidenemalononitrile by Knoevenagel condensationDraw the piperidine-catalysed Knoevenagel condensation of malononitrile with benzaldehyde: carbanion formation, addition, proton transfers and E1cB loss of hydroxide.
- 2-Metil-1-fenilpropan-1-ona por metilação com LDADesenhe a desprotonação da propiofenona pelo LDA em seu CH2 α e a metilação SN2 do enolato de lítio pelo iodometano, formando a 2-metil-1-fenilpropan-1-ona.
- Ciclopropano-1,1-dicarboxilato de dietila a partir do malonato de dietilaDesenhe as duas desprotonações do malonato de dietila por etóxido, a SN2 intermolecular no 1,2-dibromoetano e a SN2 intramolecular que fecha o ciclopropano-1,1-dicarboxilato de dietila.
- Ácido pent-4-enoico pela síntese malônicaDesenhe a síntese malônica do ácido pent-4-enoico: SN2 do enolato do malonato no brometo de alila, hidrólise ácida dos dois ésteres, descarboxilação e tautomerização do enol.
- 4-Methylpentanoic acid by malonic ester synthesis with 1-bromo-2-methylpropaneDraw the malonic ester synthesis of 4-methylpentanoic acid: malonate enolate SN2 on 1-bromo-2-methylpropane, acid hydrolysis of both esters, decarboxylation and tautomerization.
- Adição de Michael do malonato de dietila à chalconaDesenhe a desprotonação do malonato de dietila pelo etóxido, a adição conjugada do enolato do malonato ao carbono β da chalcona e a protonação do enolato resultante pelo etanol.
- 5-Nitrohexan-2-one by Michael addition of nitroethane to methyl vinyl ketoneDraw the DBU-catalysed Michael addition of the nitroethane nitronate to methyl vinyl ketone, ending with proton return that gives 5-nitrohexan-2-one.
- Cetona de Hajos–Parrish por anelação de Robinson com MVKDesenhe a anelação de Robinson da 2-metilciclopentano-1,3-diona com a metil vinil cetona: adição de Michael, protonação do enolato, fechamento de anel por aldólica intramolecular e desidratação E1cB até a cetona de Hajos–Parrish.
- Michael via enamina de Stork: ciclopentanona e acrilato de metilaDesenhe a formação da enamina de pirrolidina a partir da ciclopentanona, a adição conjugada da enamina ao acrilato de metila, a protonação do carbânion estabilizado pelo éster e a hidrólise do íon imínio.
- 3-(2-Oxocyclohexyl)propanenitrile by Stork enamine Michael additionDraw pyrrolidine enamine formation from cyclohexanone, conjugate addition of the enamine to acrylonitrile, protonation of the nitrile-stabilized carbanion, and hydrolysis of the iminium ion.
Preveja o produto 9
- Predict a crossed aldol condensationPredict the product of a crossed aldol condensation between an enolisable aldehyde and a non-enolisable aldehyde.
- Predict the Michael adductPredict the product of a Michael addition of a malonate enolate to an α,β-unsaturated ester.
- Put the Robinson annulation in orderOrder the bond-forming and bond-breaking events of a Robinson annulation.
- Which silyl enol ether forms under equilibrating conditions?Predict the major silyl enol ether of an unsymmetrical ketone when the enolates can equilibrate before trapping.
- Self-aldol condensationPredict the conjugated product of a ketone self-aldol condensation.
- ClaisenPredict the β-keto ester from an ester self-Claisen condensation.
- Ring via dialkylationPredict the carbocycle formed by double alkylation of malonate with a dihalide.
- Nitroalkene acceptorPredict the Michael adduct of malonate with a nitroalkene.
- Anelação de Robinson da 2-metilciclo-hexano-1,3-dionaPreveja a enona bicíclica formada na anelação de Robinson de uma 1,3-diona cíclica.
Classificar 5
- Which ester can only be the acceptor?Identify an ester that lacks α-hydrogens and therefore can serve only as the electrophile in a crossed Claisen condensation.
- Which reagent adds at the β-carbon?Classify nucleophiles by whether they add to the β-carbon or to the carbonyl carbon of an α,β-unsaturated ketone.
- Which acid loses CO₂ on gentle heating?Identify a β-keto acid among keto acids with the carbonyl at different positions.
- Which heats off CO2?Identify which keto acid decarboxylates on gentle heating.
- Michael ou aldólica: enolato do acetoacetato de etila e MVKClassifique a adição de um enolato estabilizado a uma cetona α,β-insaturada como Michael (1,4) ou aldólica (1,2).
Comparar 3
- Rank α-hydrogen acidityRank carbonyl compounds by the acidity of their most acidic C–H bond using the stabilisation of each enolate.
- Rank electrophiles for malonate alkylationRank alkyl halides by how well they alkylate a malonate enolate in an SN2 reaction.
- Rank enol contentRank carbonyl compounds by the fraction present as the enol at equilibrium.
Calcular 8
- Mass of CO₂ releasedCalculate the mass of CO₂ lost when a substituted malonic acid decarboxylates completely.
- Count exchangeable hydrogensCount the α-hydrogens of an unsymmetrical ketone that exchange for deuterium through enolate formation.
- Count the Dieckmann ringCount the ring size produced when a long-chain diester undergoes Dieckmann cyclisation.
- How much enolate does ethoxide make?Calculate the equilibrium constant for deprotonating a simple ketone with ethoxide and judge whether enolate formation is complete.
- How complete is LDA deprotonation?Calculate the equilibrium constant for deprotonating a ketone with LDA from the two pKa values.
- Count α-HCount the α-hydrogens of an ester to judge how many enolisation events are possible.
- How many products?Count the major Claisen products when one partner cannot form an enolate.
- Hidróxido consumido na reação do iodofórmio da acetofenonaBalanceie a reação do halofórmio de uma metilcetona e conte quanto hidróxido ela consome.
Encontre o erro 3
- Why no Dieckmann product?Diagnose a failed Dieckmann cyclisation by counting the ring the enolate would have to close.
- Why did the hydroxide alkylation fail?Diagnose why aqueous hydroxide is a poor base for alkylating a simple ketone.
- Why no tert-butylExplain why tertiary halides fail in acetoacetic ester alkylation.
Interprete as evidências 2
- Which compound was isolated?Use IR, ¹H NMR and the molecular formula to tell the Robinson annulation product from its Michael and aldol intermediates.
- RMN de 1H do acetoacetato de etila: o simpleto em 3,4 ppmAtribua um sinal de RMN de ¹H de um β-cetoéster a partir do deslocamento, da integração e do desdobramento.
Trabalhe de trás para frente 4
- Which dione closes to 3-methylcyclohex-2-en-1-one?Work backwards from a cyclic enone to the open-chain dicarbonyl compound that forms it by intramolecular aldol condensation.
- Pick the alkyl halide for a malonic ester synthesisWork backwards from a substituted acetic acid to the alkyl halide needed in a malonic ester synthesis.
- Disconnect a Michael productIdentify the Michael donor and acceptor that build a ketone carrying a 2-cyanoethyl group on its α-carbon.
- Which ketone was annulated?Identify the ketone that, with methyl vinyl ketone, gives a given Robinson annulation product.
Planeje uma síntese 4
- Plan an acetoacetic ester synthesisChoose the two alkylation steps of an acetoacetic ester synthesis that build an α-branched methyl ketone.
- Choose the base for complete enolate formationSelect a base that converts a simple ketone completely into its enolate before an alkyl halide is added.
- Pick the baseChoose conditions that form the kinetic enolate of an unsymmetrical ketone.
- 2-Etil-hexan-1-ol a partir do butanal: ordene as etapasOrdene as etapas de uma rota aldólica que dobra a cadeia de carbonos até um álcool primário ramificado.
Explique por quê 2
- Why a full equivalent of ethoxide?Explain why a Claisen condensation consumes a full equivalent of alkoxide while an aldol addition needs only a catalytic amount.
- Why do β-keto acids lose CO₂ so easily?Explain why a carbonyl group β to a carboxylic acid allows decarboxylation on gentle heating.
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