25. Condensation Chemistry

Provide the product for the following Robinson Annulation Reaction.

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

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

Predict the product of the following reactions.

a. <IMAGE>

Predict the product of the following reactions.

b. <IMAGE>

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

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Propose mechanisms for the following reactions.

(d) <IMAGE of reaction>

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.)

<IMAGE of reaction>

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.)

<IMAGE of reaction>

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) <IMAGE>

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) <IMAGE>