Textbook Question
Which stereoisomers are optically inactive?
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Ch. 4 - Isomers: The Arrangement of Atoms in Space
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
Chapter 5, Problem 89a,b
What is the configuration of the asymmetric centers in the following compounds?
a. 
b. 
Verified step by step guidance1
Step 1: Identify the asymmetric centers in each compound. An asymmetric center is a carbon atom bonded to four different groups. In compound (a), the central carbon is bonded to CH2CH2Br, CH2CH2CH3, H, and Br. In compound (b), the first carbon is bonded to BrCH2, Br, H, and the second carbon, while the second carbon is bonded to OH, H, CH=O, and the first carbon.
Step 2: Assign priorities to the substituents around each asymmetric center using the Cahn-Ingold-Prelog (CIP) priority rules. The priority is based on atomic number: the higher the atomic number, the higher the priority. For compound (a), Br has the highest priority, followed by CH2CH2Br, CH2CH2CH3, and H. For compound (b), Br has the highest priority, followed by BrCH2, H, and the second carbon for the first asymmetric center, and OH, CH=O, H, and the first carbon for the second asymmetric center.
Step 3: Orient the molecule so that the lowest priority group (H) is pointing away from you (on the dashed wedge). For compound (a), this is already the case. For compound (b), adjust the perspective for each asymmetric center to ensure the lowest priority group is pointing away.
Step 4: Determine the configuration by tracing the path of the remaining three groups in order of priority (1 → 2 → 3). If the path is clockwise, the configuration is R. If the path is counterclockwise, the configuration is S.
Step 5: Repeat the process for each asymmetric center in compound (b). For the first carbon, trace the path of Br → BrCH2 → H. For the second carbon, trace the path of OH → CH=O → H. Assign the configurations accordingly.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Asymmetric Centers
Asymmetric centers, or chiral centers, are carbon atoms bonded to four different substituents, leading to non-superimposable mirror images known as enantiomers. The configuration of these centers is crucial in determining the optical activity and specific properties of the compounds. Identifying these centers is essential for understanding the stereochemistry of organic molecules.
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How to add to asymmetrical double bonds.
Cahn-Ingold-Prelog Priority Rules
The Cahn-Ingold-Prelog (CIP) priority rules are a systematic method for assigning priorities to the substituents attached to a chiral center. According to these rules, substituents are ranked based on atomic number, with higher atomic numbers receiving higher priority. This ranking helps in determining the R (rectus) or S (sinister) configuration of the asymmetric centers.
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Stereochemistry
Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this arrangement affects their chemical behavior and properties. It encompasses concepts such as chirality, geometric isomerism, and conformational isomerism. Understanding stereochemistry is vital for predicting the reactivity and interactions of organic compounds, especially in biological systems.
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Related Practice
Textbook Question
Explain how R and S are related to (+) and (-).
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Textbook Question
Identify
5. achiral compounds
6. meso compounds
7. enantiomers
8. diastereomers
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Textbook Question
Identify
1. constitutional isomers
2. stereoisomers
3. cis–trans isomers
4. chiral compounds
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Textbook Question
Draw all the isomers with molecular formula C6H12 that contain a cyclobutane ring.
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Textbook Question
Are the following pairs identical, enantiomers, diastereomers, or constitutional isomers?
a.
b.
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