$$\mathrm{3\text{-}methyl\ cyclohex\text{-}2\text{-}en\text{-}1\text{-}one}$$

Question 1

Which of the following best describes the role of LDA (lithium diisopropylamide) in the reaction sequence shown in problem (2a)?

$$\mathrm{LDA} is $$used to:

Accepted Answer

Deprotonate the most acidic hydrogen to generate an enolate ion

Question 2

In problem (2b), what is the major product when cyclohexanone is treated with methyl iodide ($$\mathrm{CH_3I}) $$after enolate formation?

Accepted Answer

A methyl group is added to the alpha position of the cyclohexanone ring

Question 3

In the reaction shown in (2c), what is the function of $$\mathrm{CH_2Cl_2}$$?

Accepted Answer

It acts as a solvent for the reaction

Question 4

In the aldol condensation shown in (6a), what is the driving force for the formation of the final product?

Accepted Answer

The formation of a new carbon-carbon bond and the loss of water

Question 5

Which of the following best describes the product of the reaction between benzaldehyde and propanal under basic conditions, as shown in (6b)?

Accepted Answer

An α,β-unsaturated aldehyde

Question 6

In the reaction (7a), 2,6-heptanedione undergoes intramolecular aldol condensation. What is the major product?

Accepted Answer

3-methylcyclohex-2-en-1-one

Question 7

In the reaction (8a), what type of reaction is occurring when the ester is converted to a β-keto ester?

Accepted Answer

Claisen condensation

Question 8

In problem (9), what is the product when methyl benzoate reacts with cyclohexanone under basic conditions?

Accepted Answer

A β-diketone

Question 9

In the reaction (10), what is the purpose of adding $$\mathrm{I_2$}$$ after the initial steps?

Accepted Answer

To test for the presence of a methyl ketone via the iodoform reaction

Question 10

In the reaction sequence (11), what is the key intermediate formed before the final product?

Accepted Answer

An enolate ion

Question 11

In the reaction (12), which mechanism best explains the formation of the polycyclic product?

Accepted Answer

Intramolecular aldol condensation followed by cyclization

Question 12

Which of the following statements about the Claisen condensation is correct?

Accepted Answer

It requires two esters or one ester and one ketone with at least one α-hydrogen

Question 13

Which of the following is a necessary condition for a successful aldol condensation?

Accepted Answer

At least one reactant must have α-hydrogens

Question 14

In the iodoform test, which functional group is detected by the formation of a yellow precipitate?

Accepted Answer

Methyl ketone

Question 15

Which of the following best explains why β-diketones are more acidic than simple ketones?

Accepted Answer

The enolate ion is stabilized by resonance with both carbonyl groups

Question 16

Which product is expected from the intramolecular aldol condensation of 2,6-heptanedione?

Accepted Answer

$$\mathrm{3	ext{-}methyl\ cyclohex	ext{-}2	ext{-}en	ext{-}1	ext{-}one}$$

Organic Chemistry CH22 Practice: Enolate and Carbonyl Chemistry

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