Some (but not all) of the following keto esters can be formed by Dieckmann condensations. Determine which ones are possible, and draw the starting diesters.

Some (but not all) of the following keto esters can be formed by Dieckmann condensations. Determine which ones are possible, and draw the starting diesters.

(a)

(b)

Some (but not all) of the following keto esters can be formed by Dieckmann condensations. Determine which ones are possible, and draw the starting diesters.

(c)

(d)

Propose a mechanism for the crossed Claisen condensation between ethyl acetate and ethyl benzoate.

Predict the products from crossed Claisen condensation of the following pairs of esters. Indicate which combinations are poor choices for crossed Claisen condensations.

(a)

(b)

Predict the products from crossed Claisen condensation of the following pairs of esters. Indicate which combinations are poor choices for crossed Claisen condensations.

(c)

(d)

Show how crossed Claisen condensations could be used to prepare the following esters.

(a)

Show how crossed Claisen condensations could be used to prepare the following esters.

(b)

Show how crossed Claisen condensations could be used to prepare the following esters.

(c)

(d)

Predict the major products of the following crossed Claisen condensations.

(a)

Predict the major products of the following crossed Claisen condensations.

(b)

Predict the major products of the following crossed Claisen condensations.

(c)

Show how Claisen condensations could be used to make the following compounds.

(a)

Show how Claisen condensations could be used to make the following compounds.

(b)

Show how Claisen condensations could be used to make the following compounds.

(c)

Show how Claisen condensations could be used to make the following compounds.

(d)

Show the resonance forms for the enolate ions that result when the following compounds are treated with a strong base.

(a) ethyl acetoacetate

(b) pentane-2,4-dione

Show the resonance forms for the enolate ions that result when the following compounds are treated with a strong base.

(c) ethyl α-cyanoacetate

Show the resonance forms for the enolate ions that result when the following compounds are treated with a strong base.

(d) nitroacetone

Show how the following compounds can be made using the malonic ester synthesis.

(a) 3-phenylpropanoic acid

(b) 2-methylpropanoic acid

Show how the following compounds can be made using the malonic ester synthesis.

(c) 4-phenylbutanoic acid

(d) cyclopentanecarboxylic acid

Show the ketones that would result from hydrolysis and decarboxylation of the following β-keto esters.

Show how the following ketones might be synthesized by using the acetoacetic ester synthesis.

In Solved Problem 22-9, the target molecule was synthesized using a Michael addition to form the bond that is β,γ to the upper carbonyl group. Another approach is to use a Michael addition to form the bond that is β,γ to the other (lower) carbonyl group. Show how you would accomplish this alternative synthesis.

Show how cyclohexanone might be converted to the following δ-diketone (Hint: Stork).

Show how an acetoacetic ester synthesis might be used to form a δ-diketone such as heptane-2,6-dione.

Propose a mechanism for the conjugate addition of a nucleophile (Nuc:^–) to acrylonitrile (H₂C=CHCN). Use resonance forms to show how the cyano activate the double bond toward conjugate addition.

Propose a mechanism for the conjugate addition of a nucleophile (Nuc:^–) to acrylonitrile (H₂C=CHCN) and to nitroethylene. Use resonance forms to show how the cyano and nitro groups activate the double bond toward conjugate addition.

Show how the following products might be synthesized from suitable Michael donors and acceptors.

(a)

Show how the following products might be synthesized from suitable Michael donors and acceptors.

(b)