Problem 16
Question
In the reaction \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{C}=\mathrm{O} \frac{1 . \mathrm{CH}_{3} \mathrm{MgBr}}{2 . \mathrm{H}_{2} \mathrm{O}}{\rightarrow} \mathrm{X}\) The product \((X)\) is (a) \(\mathrm{CH}_{3} \mathrm{OH}\) (b) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\) (c) \(\mathrm{CH}_{3} \mathrm{CHOHCH}_{3}\) (d) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}\)
Step-by-Step Solution
Verified Answer
The product \((X)\) is \((\mathrm{CH}_{3})_{3} \mathrm{COH}\), option (d).
1Step 1: Identify Reaction Components
The reaction involves an organic compound \((\mathrm{CH}_{3})_{2} \mathrm{C}=\mathrm{O}\), also known as acetone, reacting with a Grignard reagent \(\mathrm{CH}_{3} \mathrm{MgBr}\) and water (\(\mathrm{H}_{2} \mathrm{O}\)).
2Step 2: Recognize Grignard Reaction Mechanism
Grignard reagents add to carbonyl groups like ketones (\((\mathrm{CH}_{3})_{2} \mathrm{C}=\mathrm{O}\)) to form tertiary alcohols upon hydrolysis. Here, \(\mathrm{CH}_{3} \mathrm{MgBr}\) acts as a source of \(\mathrm{CH}_{3}^{-}\) which attacks the carbonyl carbon.
3Step 3: Determine the Addition Product
The \(\mathrm{CH}_{3}^{-}\) from \(\mathrm{CH}_{3} \mathrm{MgBr}\) attacks the electrophilic carbonyl carbon of acetone, resulting in the addition of a \(\mathrm{CH}_{3}\) group, making the structure \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CO}^{-}\).
4Step 4: Hydrolysis of Addition Product
The intermediate \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CO}^{-}\) is then hydrolyzed by water \(\mathrm{H}_{2} \mathrm{O}\), leading to the formation of the alcohol \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}\).
5Step 5: Confirm the Final Product
The final product of the reaction is the tertiary alcohol \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}\), which corresponds to option (d).
Key Concepts
Carbonyl GroupTertiary AlcoholHydrolysisAcetoneGrignard Reagent
Carbonyl Group
A carbonyl group is a functional group present in a wide range of organic compounds. It consists of a carbon atom double-bonded to an oxygen atom, represented as \((C=O)\). This double bond is highly polar, which makes the carbon atom electrophilic, or electron-loving.
In the context of Grignard reactions, the carbonyl group plays a crucial role as a reactive site.
When a Grignard reagent is introduced, it attacks the electrophilic carbon of the carbonyl group, initiating the formation of an alcohol.
Carbonyl groups are found in many structures, including aldehydes, ketones, carboxylic acids, and esters, each of which behaves differently in reactions. In our exercise, the carbonyl group is on an acetone molecule, which is a simple ketone.
In the context of Grignard reactions, the carbonyl group plays a crucial role as a reactive site.
When a Grignard reagent is introduced, it attacks the electrophilic carbon of the carbonyl group, initiating the formation of an alcohol.
Carbonyl groups are found in many structures, including aldehydes, ketones, carboxylic acids, and esters, each of which behaves differently in reactions. In our exercise, the carbonyl group is on an acetone molecule, which is a simple ketone.
Tertiary Alcohol
Tertiary alcohols are a specific type of alcohol characterized by a hydroxyl group (\((OH)\)) attached to a carbon atom, which is also connected to three other carbon atoms.
This structure results in a central carbon atom that is saturated with other carbon atoms. It influences both the reactivity and properties of tertiary alcohols.
In our exercise, the Grignard reagent reacts with acetone to form a tertiary alcohol, \((CH_3)_3COH\), also known as tert-Butyl alcohol. This conversion is a classic example of how the addition of nucleophiles to carbonyl groups can form new carbon-carbon bonds, leading to alcohols.
This structure results in a central carbon atom that is saturated with other carbon atoms. It influences both the reactivity and properties of tertiary alcohols.
In our exercise, the Grignard reagent reacts with acetone to form a tertiary alcohol, \((CH_3)_3COH\), also known as tert-Butyl alcohol. This conversion is a classic example of how the addition of nucleophiles to carbonyl groups can form new carbon-carbon bonds, leading to alcohols.
Hydrolysis
Hydrolysis is a critical process in chemistry, where water is used to split molecules into smaller parts. In the context of this reaction, hydrolysis plays a pivotal role in converting the intermediate organometallic compound into an alcohol.
The reaction begins with the Grignard reagent attacking the carbonyl group, resulting in an alkoxide ion, \((CH_3)_3CO^-\).
Water then acts as a proton source that reacts with the alkoxide ion, forming the final product: the tertiary alcohol. Hydrolysis here ensures that the reactive intermediate is quenched, transitioning from a potentially hazardous ion to a stable alcohol formation.
The reaction begins with the Grignard reagent attacking the carbonyl group, resulting in an alkoxide ion, \((CH_3)_3CO^-\).
Water then acts as a proton source that reacts with the alkoxide ion, forming the final product: the tertiary alcohol. Hydrolysis here ensures that the reactive intermediate is quenched, transitioning from a potentially hazardous ion to a stable alcohol formation.
Acetone
Acetone, or propanone, is the simplest and most common ketone with the chemical formula \((CH_3)_2CO\).
It is known for being a solvent and cleaning agent, but in organic chemistry, especially in Grignard reactions, its role is more reactive.
The carbonyl group of acetone is highly susceptible to nucleophilic attack. In our synthesis exercise, acetone's carbonyl carbon participates actively by reacting with the Grignard reagent, leading to the formation of a higher-order alcohol.
It is known for being a solvent and cleaning agent, but in organic chemistry, especially in Grignard reactions, its role is more reactive.
The carbonyl group of acetone is highly susceptible to nucleophilic attack. In our synthesis exercise, acetone's carbonyl carbon participates actively by reacting with the Grignard reagent, leading to the formation of a higher-order alcohol.
Grignard Reagent
Grignard reagents are organometallic compounds typically containing magnesium halides, such as \(( CH_3MgBr )\). These reagents are known for their strong nucleophilic properties.
In organic synthesis, they are prized for their ability to form new carbon-carbon bonds.
When a Grignard reagent comes in contact with a carbonyl compound, it adds onto the carbon, creating a new alkoxide ion.
The Grignard reaction, involving the conversion of acetone with methyl magnesium bromide as described in this exercise, illustrates this process. The new bond formation is crucial for stepping up the molecular complexity of the product, which in our case, results in a tertiary alcohol.
In organic synthesis, they are prized for their ability to form new carbon-carbon bonds.
When a Grignard reagent comes in contact with a carbonyl compound, it adds onto the carbon, creating a new alkoxide ion.
The Grignard reaction, involving the conversion of acetone with methyl magnesium bromide as described in this exercise, illustrates this process. The new bond formation is crucial for stepping up the molecular complexity of the product, which in our case, results in a tertiary alcohol.
Other exercises in this chapter
Problem 14
When acetone is saturated with dry HCl gas, it undergoes a condensation reaction to form a trimer. The trimer is (a) Phorone (b) mesityl oxide (c) mesitylene (d
View solution Problem 15
lodoform test is not given by : (a) 2-pentanone (b) 3-pentanone (c) Ethanal (d) Ethanol
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In the given reaction : \(\mathrm{CH}_{3}-\mathrm{CHO} \stackrel{\mathrm{SeO}_{2}}{\longrightarrow}[\mathrm{X}]\) [X] will be: (a) Ethanoic acid (b) Methanoic a
View solution Problem 18
Hybridization of carbonyl carbon in benzaldehyde is: (a) \(\mathrm{sp}^{2}\) (b) \(\mathrm{sp}^{3}\) (c) \(\mathrm{sp}\) (d) \(\mathrm{sp}^{3} \mathrm{~d}\)
View solution