I need help with question #4 The reaction of acetone with benzaldehyde in the presence of a base is a classic aldol condensation reaction. Depending on the stoichiometryand conditions of the reaction, these reagents can be used to prepare benzalketone or dibenzalketone. The conditions to be used in thisexperiment favor the formation of dibenzalketone.H.NaOH, H2O,C.+21H3C CH3H.CH3CH2OHH.H.AcetoneBenzaldehydeMolar mass = 106 g/molDensity = 1.04 g/mLAn excess will be usedOriginal carbons of acetoneMolar mass 58 g/molDensity: 0.79 g/mLLimited reactantDibenzalcetoneMolar mass = 234 g/mLMelting point between80 and 120° CThe reaction in this experiment is carried out by adding a mixture of two parts benzaldehyde and one partacetone to a solution made with aqueous ethanol and NaOH. The solvent, aqueous ethanol, also favors theformation of dibenzalketone. The reason is that the reactants and intermediates, including dibenzalketone, aresoluble in aqueous ethanol and are not removed from the reaction solution by simple separation or precipitation.Dibenzalketone, however, is insoluble in aqueous ethanol - while the reaction mixture is being stirred, the darkyellow dibenzalketone slowly precipitates out of solution. How does the benzoic acid in the benzaldehyde used in this experiment affectthe reaction?Suggest another way (besides vacuum filtration) to purify the partiallyoxidized benzaldehyde.Suggest ways to modify the procedure of this experiment so that the reactionproduces benzalketone instead of dibenzalketone.4.2.3.

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Suggest ways to modify the procedure of this experiment produces benzalketone instead of dibenzalketone. 4. so that the reaction

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter24: Catalytic Carbon-carbon Bond Formation

Section: Chapter Questions

Problem 24.9P

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base 2 H3C H H3C OH heat H H3C + H₂O H The aldol reaction is a carbonyl condensation reaction between two carbonyl partners and involves a combination of nucleophilic addition and a-substitution steps. One partner is converted into an enolate ion nucleophile and adds to the electrophilic carbonyl group of the second partner. In the classic aldol reaction, the carbonyl partners are aldehydes or ketones, although aldehydes are more reactive. The product is a ẞ-hydroxy carbonyl compound. Under reaction conditions slightly more vigorous than those employed for the aldol reaction, the ẞ-hydroxyl group is eliminated in an E1CB dehydration to give an a,ẞ-unsaturated carbonyl compound. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions X :OH H₂O: а کی H₂C H H₂C H H
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Step 3: If excess alcohol is present in the hemiacetal, the hemiacetal can be further converted to an acetal product, but only in the presence of acid. R₁ R₂ R3OH, H+ HO OR3 R3OH, H+ R3Q OR 3 + H2O R₁ R₁ R₂ hemiacetal acetal Why is acid required? The alkoxy group in the hemiacetal must first be converted into a good leaving group. Acid stabilizes the product. Acid stabilizes the hemiacetal, making it more reactive. The hydroxy group in the hemiacetal must first be converted into a good leaving group.
I H H3C NOC XT :0: MET H₂C base H3C The aldol reaction is a carbonyl condensation reaction between two carbonyl partners and involves a combination of nucleophilic addition and a-substitution steps. One partner is converted into an enolate ion nucleophile and adds to the electrophilic carbonyl group of the second partner. In the classic aldol reaction, the carbonyl partners are aldehydes or ketones, although aldehydes are more reactive. The product is a ß-hydroxy carbonyl compound. H OH q H3C H₂C H Under reaction conditions slightly more vigorous than those employed for the aldol reaction, the ß-hydroxyl group is eliminated in an E1cB dehydration to give an a,ß-unsaturated carbonyl compound. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions heat H H + H₂O
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3. Robison annulation involves a Michael addition followed by aldol condensation. The reaction is named after the English chemist, Sir Robert Robinson who won the Nobel Prize in Chemistry in 1947. For the following Robinson annulation reaction, provide the Michael addition product E and the final cyclized product F. Propose step by step mechanism for both transformations. Michael Addition Intramolecular aldol - OH, CH3OH E CH3 condensation F