The observation that when optically active (R)-2-methylcyclohexanone is treated with either aqueous base or acid, racemization occurs is to be explained. Concept introduction: During racemization the optically active ketone first yields an achiral, planar enol intermediate. When the intermediate reverts back to the chiral ketone there is equal probability of the formation of both enantiomers which leads to racemization. If the chiral carbon does not take part in enol formation, then the resulting product will be optically active.

Question

When (R)-6-bromo-2,6-dimethylnonane is dissolved in CH3OH, nucleophilic substitution yields an optically inactive solution. When the isomeric halide (R)-2-bromo-2,5-dimethylnonane is dissolved in CH3OH under the same conditions, nucleophilic substitution forms an optically active solution. Draw the products formed in each reaction, and explain why the difference in optical activity is observed.

Answer 1

Question

Definition Definition Organic compounds that have a carbonyl group, C = O, as their functional group. The carbonyl group in ketones is placed somewhere in the middle of the molecular structure, which means, the C=O is attached to two alkyl groups or benzene rings. Just like all other homologous series, the naming of ketones is done using a common suffix “-one”. The general molecular formula is C n H 2n O. Functional group of a ketone

Chapter 22.SE, Problem 51AP

Interpretation Introduction

Interpretation:

The observation that when optically active (R)-2-methylcyclohexanone is treated with either aqueous base or acid, racemization occurs is to be explained.

Concept introduction:

During racemization the optically active ketone first yields an achiral, planar enol intermediate. When the intermediate reverts back to the chiral ketone there is equal probability of the formation of both enantiomers which leads to racemization. If the chiral carbon does not take part in enol formation, then the resulting product will be optically active.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Students have asked these similar questions

When (R)-6-bromo-2,6-dimethylnonane is dissolved in CH3OH, nucleophilic substitution yields an optically inactive solution. When the isomeric halide (R)-2-bromo-2,5-dimethylnonane is dissolved in CH3OH under the same conditions, nucleophilic substitution forms an optically active solution. Draw the products formed in each reaction, and explain why the difference in optical activity is observed.

(a) Draw the products (including stereoisomers) formed when 2methylhex-2-ene is treated with HBr in the presence of peroxides. (b) Draw the products (including stereoisomers) formed when (S)-2,4dimethylhex-2-ene is treated with HBr and peroxides under similar conditions.

Explain why methyl trifluoroacetate, CF3CO2CH3, is more reactive than methyl acetate, CH3CO2CH3, in nucleophilic acyl substitution reactions.

Answer 2

Question

Definition Definition Organic compounds that have a carbonyl group, C = O, as their functional group. The carbonyl group in ketones is placed somewhere in the middle of the molecular structure, which means, the C=O is attached to two alkyl groups or benzene rings. Just like all other homologous series, the naming of ketones is done using a common suffix “-one”. The general molecular formula is C n H 2n O. Functional group of a ketone

Chapter 22.SE, Problem 51AP

Interpretation Introduction

Interpretation:

The observation that when optically active (R)-2-methylcyclohexanone is treated with either aqueous base or acid, racemization occurs is to be explained.

Concept introduction:

During racemization the optically active ketone first yields an achiral, planar enol intermediate. When the intermediate reverts back to the chiral ketone there is equal probability of the formation of both enantiomers which leads to racemization. If the chiral carbon does not take part in enol formation, then the resulting product will be optically active.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Answer 3

Question

Definition Definition Organic compounds that have a carbonyl group, C = O, as their functional group. The carbonyl group in ketones is placed somewhere in the middle of the molecular structure, which means, the C=O is attached to two alkyl groups or benzene rings. Just like all other homologous series, the naming of ketones is done using a common suffix “-one”. The general molecular formula is C n H 2n O. Functional group of a ketone

Chapter 22.SE, Problem 51AP

Interpretation Introduction

Interpretation:

The observation that when optically active (R)-2-methylcyclohexanone is treated with either aqueous base or acid, racemization occurs is to be explained.

Concept introduction:

During racemization the optically active ketone first yields an achiral, planar enol intermediate. When the intermediate reverts back to the chiral ketone there is equal probability of the formation of both enantiomers which leads to racemization. If the chiral carbon does not take part in enol formation, then the resulting product will be optically active.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Answer 4

Question

Definition Definition Organic compounds that have a carbonyl group, C = O, as their functional group. The carbonyl group in ketones is placed somewhere in the middle of the molecular structure, which means, the C=O is attached to two alkyl groups or benzene rings. Just like all other homologous series, the naming of ketones is done using a common suffix “-one”. The general molecular formula is C n H 2n O. Functional group of a ketone

Chapter 22.SE, Problem 51AP

Interpretation Introduction