Textbook Question
Show how the following compounds can be prepared from the given starting materials. You can use any necessary organic or inorganic reagents.
a.
22. Carboxylic Acid Derivatives: NAS
Nucleophilic Acyl Substitution
3:00 minutesProblem 50j
Textbook Question
Predict the products of the following reactions.
(j) 
Verified step by step guidance1
Step 1: Analyze the first reaction. The starting compound is a nitrile (cyclopentyl nitrile), and the reagents are CH3MgI (a Grignard reagent) followed by H3O+ (acidic hydrolysis). Grignard reagents react with nitriles to form imines, which are then hydrolyzed under acidic conditions to yield ketones.
Step 2: In the first reaction, the CH3MgI adds to the carbon of the nitrile group (C≡N), breaking the triple bond and forming an intermediate imine. The imine is then hydrolyzed by H3O+ to produce a ketone. The final product will be cyclopentyl methyl ketone.
Step 3: Analyze the second reaction. The starting compound is a lactam (cyclic amide), and the reagents are NaOH and H2O. Under basic conditions, lactams undergo hydrolysis to yield the corresponding amino acid.
Step 4: In the second reaction, NaOH breaks the amide bond in the lactam, resulting in the formation of a carboxylate group and an amine group. The product will be 6-aminocaproic acid (the open-chain form of the lactam).
Step 5: Summarize the transformations: (i) Cyclopentyl nitrile reacts with CH3MgI and H3O+ to form cyclopentyl methyl ketone. (ii) The lactam reacts with NaOH and H2O to yield 6-aminocaproic acid.
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3mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nitrile Reactivity
Nitriles are organic compounds containing a cyano group (-C≡N). They can undergo nucleophilic addition reactions, where a nucleophile attacks the carbon atom of the cyano group. In this case, CH3MgI (a Grignard reagent) acts as a strong nucleophile, adding a methyl group to the nitrile, ultimately leading to the formation of an intermediate that can be hydrolyzed to yield an amine.
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Nitrile Nomenclature
Grignard Reagents
Grignard reagents, such as CH3MgI, are organomagnesium compounds that are highly reactive and serve as nucleophiles in organic synthesis. They can react with electrophiles, such as carbonyls and nitriles, to form new carbon-carbon bonds. The reaction with a nitrile results in the formation of an imine intermediate, which can be further hydrolyzed to produce a primary amine after treatment with water or acid.
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Hydrolysis of Nitriles
Hydrolysis is the chemical process in which a compound reacts with water, leading to the breakdown of that compound. In the context of nitriles, after the addition of a Grignard reagent, the subsequent treatment with H3O+ (acidic water) facilitates the conversion of the intermediate into a carboxylic acid and an amine. This step is crucial for completing the transformation of the nitrile into a more functionalized product.
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