21. Aldehydes and Ketones: Nucleophilic Addition

For each compound,

1. name the functional group.

2. show what compound(s) result from complete hydrolysis.

(a)

The nucleosides that make up DNA have heterocyclic rings linked to deoxyribose by an aminoacetal functional group. Point out the aminoacetal linkages in deoxycytidine and deoxyadenosine.

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

(e) propane-1,3-diol, H⁺

Predict the major products of the following reactions.

(e)

A chemist failed to generate the alcohol using the reaction shown here.

(b) How could the reaction conditions be modified to allow formation of the product?

Show how each of the following compounds could be prepared from the given starting material. Each requires a protecting group.

c.

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.

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