25. Condensation Chemistry

Predict the product of the following reactions.

(b)

Which of the following pairs of starting materials would result in the formation of 2-methyl-1,2,3,4-tetralone via a Robinson annulation?

Draw the product obtained by heating each pair of ketones in a basic solution.

a.

Provide the product for the following Robinson Annulation Reaction.

Show how you would use the Robinson annulation to synthesize the following compounds.

(c)

Show how you would use Robinson annulations to synthesize the following compounds. Work backward, remembering that the cyclohexenone is the new ring and that the double bond of the cyclohexenone is formed by the aldol with dehydration. Take apart the double bond, then see what structures the Michael donor and acceptor must have.

(a)

Propose a mechanism for the following reaction.

Show how you would use the Robinson annulation to synthesize the following compounds.

(a)

What two carbonyl compounds are needed to synthesize each of the following compounds, using a Robinson annulation?

a.

Predict the product of the following reactions.

(a)

The base-catalyzed reaction of an aldehyde (having no α hydrogens) with an anhydride is called the Perkin condensation. Propose a mechanism for the following example of the Perkin condensation. (Sodium acetate serves as the base.)

Show how the following molecule might be synthesized using the Robinson annulation.

Propose mechanisms for the following reactions.

(d)

How would you prepare the following compound using a Robinson annulation reaction between a ketone and an alpha, beta unsaturated ketone?

Show how you would use Robinson annulations to synthesize the following compounds. Work backward, remembering that the cyclohexenone is the new ring and that the double bond of the cyclohexenone is formed by the aldol with dehydration. Take apart the double bond, then see what structures the Michael donor and acceptor must have.

(b)