Skip to main content
Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions
Bruice - Organic Chemistry 8th Edition
Bruice8th EditionOrganic ChemistryISBN: 9780135213711Not the one you use?Change textbook
All textbooksBruice 8th EditionCh. 22 - Catalysis in Organic Reactions and in Enzymatic ReactionsProblem 41c
Chapter 23, Problem 41c

2-Acetoxycyclohexyl tosylate reacts with acetate ion to form 1,2-cyclohexanediol diacetate. The reaction is stereospecific—that is, the stereoisomers obtained as products depend on the stereoisomer used as a reactant. Recall that because 2-acetoxycyclohexyl tosylate has two asymmetric centers, it has four stereoisomers—two are cis and two are trans. Explain the following observations:
c. A trans reactant is more reactive than a cis reactant.
Chemical reaction diagram showing 2-acetoxycyclohexyl tosylate converting to 1,2-cyclohexanediol diacetate.

Verified step by step guidance
1
The reaction involves a nucleophilic substitution mechanism where the acetate ion (CH₃CH₂CO⁻) attacks the 2-acetoxycyclohexyl tosylate. The stereochemistry of the reactant plays a crucial role in determining the reactivity and the stereospecificity of the product.
In the trans isomer, the two substituents (acetoxy and tosylate groups) are positioned on opposite sides of the cyclohexane ring. This arrangement reduces steric hindrance and allows the acetate ion to approach the tosylate group more easily, facilitating the reaction.
In the cis isomer, the acetoxy and tosylate groups are on the same side of the cyclohexane ring. This creates steric hindrance, making it more difficult for the acetate ion to access the tosylate group and slowing down the reaction.
The stereospecificity of the reaction is due to the fact that the acetate ion attacks the tosylate group in a manner that preserves the stereochemistry of the cyclohexane ring. The trans reactant leads to a product with a specific stereochemical configuration, while the cis reactant leads to a different stereochemical configuration.
The observation that the trans reactant is more reactive than the cis reactant can be explained by the reduced steric hindrance in the trans isomer, which allows for a faster and more efficient nucleophilic substitution reaction.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
13m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stereochemistry

Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In this reaction, the stereochemistry of the reactants influences the stereochemical outcome of the products. The presence of asymmetric centers in the reactants leads to different stereoisomers, which can exhibit varying reactivity based on their spatial configuration.
Recommended video:
1:38
Polymer Stereochemistry Concept 1

Reactivity of Stereoisomers

The reactivity of stereoisomers can differ significantly due to steric and electronic factors. In this case, the trans isomer is more reactive than the cis isomer, likely due to less steric hindrance and more favorable orbital overlap during the reaction with the acetate ion. This increased reactivity can lead to a faster reaction rate and a preference for the trans isomer in product formation.
Recommended video:
Guided course
01:58
Determining when molecules are stereoisomers.

Nucleophilic Substitution

Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile attacks an electrophile, resulting in the replacement of a leaving group. In this scenario, the acetate ion acts as the nucleophile attacking the 2-acetoxycyclohexyl tosylate. The stereospecific nature of the reaction means that the configuration of the starting material directly influences the stereochemistry of the product.
Recommended video:
Guided course
01:47
Nucleophiles and Electrophiles can react in Substitution Reactions.
Related Practice
Textbook Question

Carbonic anhydrase is an enzyme that catalyzes the conversion of carbon dioxide to bicarbonate ion. It is a metalloenzyme, with Zn2+ coordinated at the active site by three histidine side chains. Propose a mechanism for the reaction.

134
views
Textbook Question

2-Acetoxycyclohexyl tosylate reacts with acetate ion to form 1,2-cyclohexanediol diacetate. The reaction is stereospecific—that is, the stereoisomers obtained as products depend on the stereoisomer used as a reactant. Recall that because 2-acetoxycyclohexyl tosylate has two asymmetric centers, it has four stereoisomers—two are cis and two are trans. Explain the following observations:

b. Both trans reactants form the same racemic mixture.

1168
views
Textbook Question

3-Amino-2-oxindole catalyzes the decarboxylation of a-keto acids.

a. Propose a mechanism for the catalyzed reaction.

1129
views
Textbook Question

Proof that an imine was formed between aldolase and its substrate was obtained by using D-fructose-1,6-bisphosphate labeled at the C-2 position with 14C as the substrate. NaBH4 was added to the reaction mixture. A radioactive product was isolated from the reaction mixture and hydrolyzed in an acidic solution. Draw the structure of the radioactive product obtained from the acidic solution. (Hint: NaBH4 reduces an imine linkage.)

1320
views
Textbook Question

Explain why the alkyl halide shown here reacts much more rapidly with guanine than does a primary alkyl halide (such as pentyl chloride).

1081
views
Textbook Question

2-Acetoxycyclohexyl tosylate reacts with acetate ion to form 1,2-cyclohexanediol diacetate. The reaction is stereospecific—that is, the stereoisomers obtained as products depend on the stereoisomer used as a reactant. Recall that because 2-acetoxycyclohexyl tosylate has two asymmetric centers, it has four stereoisomers—two are cis and two are trans. Explain the following observations:

a. Both cis reactants form an optically active trans product, but each cis reactant forms a different trans product.

2114
views