Textbook: McMurry 8th Ed. (2011)

Chapter 21: Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions

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Problem # 669
 

In your own words, what is the major difference in the addition of a Grignard reagent to an oxidation state III carbonyl (ester/acid chloride) versus an oxidation state II carbonyl? (aldehyde/ketone)

Problem # 724

Use curved arrows to show the formation of the tetrahedral intermediate of a Fischer esterification reaction (shown below). There are three steps in total.

Problem # 729

The ester below was dissolved in a solution of water, a small amount of which was isotopically labeled with O-18, denoted with an asterisk.

After a few hours, some isotopically labeled oxygen was found in the ester. Where was it found in the ester? Can you explain why?

Problem # 730

N,N-dimethylformamide (DMF) is shown below. Based on its structure, you might expect to see only one -CH3 signal in the 1H NMR spectrum. But instead DMF shows two different -CH3 signals. Explain.

Problem # 670
 

Draw out the mechanism for the addition of excess phenyl Grignard to the carbonyl compound below.

Problem # 708

The overall mechanism for Fischer esterification is shown below. This isn't a real mechanism, just an outline.

Methanol (the nucleophile) attacks the carbonyl carbon, forming a tetrahedral intermediate, which then loses a water to reform the carbonyl. This mechanism is called nucleophilic acyl substitution.

 

Use curved arrows to draw a full mechanism for this reaction. I've included structures for you to use as a guide.

This reaction takes place under acidic conditions, so the mechanism you draw will be similar to those in problem 706.

Problem # 725

A chemist carried out a Fischer esterification using methanol that was isotopically labeled with 18O (indicated with an asterisk).

Which one of the esters below (A-D) was formed?

Problem # 726

Show two esters that would yield the two alcohols below after treatment with lithium aluminum hydride.

Problem # 727

Show how the ester below can be prepared from propene.

Problem # 728

The acyl group is a protecting group for amines. Amines can be acylated using acetic anhydride, and deacylated with base.

Propose a mechanism for each reaction.