Chapter 19, Problem 19.51P

Interpretation Introduction

(a)

Interpretation:

The effective way to carry out the given synthesis is to be explained along with the way which is not effective.

Concept introduction:

A protecting group temporarily converts a functional group into one that is unreactive under the conditions necessary for a step in the synthesis. Ketones, aldehydes, and alcohols can often be protected in the form of an acetal or ether. Silyl ether derivatives like TBDMSCl are used to protect the OH group; reactivity of ketones and alcohols is similar. The $\text{C=O}$ group of the aldehyde and ketones is protected by treating it with ethylene glycol ${\text{(HOCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH)}$ under acidic condition. A Grignard reagent can add the alkyl group to the electrophilic C atom.

Interpretation Introduction

(b)

Interpretation:

The effective way to carry out the given synthesis is to be explained along with the way which is not effective.

Concept introduction:

A protecting group temporarily converts a functional group into one that is unreactive under the conditions necessary for a step in the synthesis. Ketones, aldehydes, and alcohols can often be protected in the form of an acetal or ether. Silyl ether derivatives like TBDMSCl are used to protect the OH group; reactivity of ketones and alcohols is similar. The $\text{C=O}$ group of the aldehyde and ketones is protected by treating it with ethylene glycol ${\text{(HOCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH)}$ under acidic condition. A Grignard reagent can add the alkyl group to the electrophilic C atom.