21. Aldehydes and Ketones: Nucleophilic Addition

As discussed in Section 17.9.1, alkenes can be hydrogenated selectively in the presence of ketones. Suppose that was not the case, and suggest how you might use a protecting group strategy to generate A from B.

Show how you would synthesize the following derivatives from appropriate carbonyl compounds.

(d)

Acetals can serve as protecting groups for 1,2-diols, as well as for aldehydes and ketones. When the acetal is formed from acetone plus the diol, the acetal is called an acetonide. Show the acetonides formed from these diols with acetone under acid catalysis.

Acetals can serve as protecting groups for 1,2-diols, as well as for aldehydes and ketones. When the acetal is formed from acetone plus the diol, the acetal is called an acetonide. Show the acetonides formed from these diols with acetone under acid catalysis.

What starting materials are required to synthesize the following compounds, using the Fischer indole synthesis?

c.

Show what amines and carbonyl compounds combine to give the following derivatives.

(d)

Show what amines and carbonyl compounds combine to give the following derivatives.

(f)

Draw structures of the following derivatives.

(a) the 2,4-dinitrophenylhydrazone of benzaldehyde

Draw structures of the following derivatives.

(b) the semicarbazone of cyclobutanone

Draw structures of the following derivatives.

(c) cyclopropanone oxime

Predict the products formed when cyclohexanone reacts with the following reagents.

(e) phenylhydrazine and weak acid

Draw a mechanism for the reaction of propanoyl chloride with 2 moles of phenylmagnesium bromide.

What are the products of the following reactions?

b.

Suggest a series of steps involving a cuprate reagent that would convert the reactant on the left to the product on the right. The ideal number of steps is shown.

(b)

Predict the product of the following reaction sequences.

(b)