Textbook Question
a. Is (R)-lactic acid dextrorotatory or levorotatory?
b. Is (R)-sodium lactate dextrorotatory or levorotatory?
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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 30a,b
What is the configuration of the following compounds? (Use the given structures to answer the question.)
a. ()-glyceric acid
b. ()-isoserine
Verified step by step guidance1
Step 1: Identify the chiral center in each compound. Both (-)-glyceric acid and (+)-isoserine have one chiral center, which is the carbon atom bonded to four different groups.
Step 2: Assign priorities to the substituents attached to the chiral center based on the Cahn-Ingold-Prelog priority rules. For (-)-glyceric acid, the groups are COOH, CH2OH, H, and OH. For (+)-isoserine, the groups are COOH, CH2NH3+, H, and OH.
Step 3: Orient the molecule so that the lowest priority group (H) is pointing away from you (on the dashed wedge). This allows you to determine the configuration by tracing the path of the remaining groups in order of priority.
Step 4: Trace the path from the highest priority group to the second and third priority groups. If the path is clockwise, the configuration is R. If the path is counterclockwise, the configuration is S.
Step 5: Use the given labels (-) and (+) to confirm the optical activity of the compounds. (-)-glyceric acid is levorotatory, and (+)-isoserine is dextrorotatory. This does not affect the R/S configuration but provides additional information about the compounds.
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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. It is crucial for understanding the configuration of compounds, particularly in organic chemistry, where the three-dimensional orientation of atoms can lead to different isomers with distinct properties.
Chirality
Chirality refers to the property of a molecule that makes it non-superimposable on its mirror image, much like left and right hands. Chiral molecules often have one or more stereocenters, which are carbon atoms bonded to four different substituents, leading to different configurations known as enantiomers. Understanding chirality is essential for determining the configuration of compounds.
Cahn-Ingold-Prelog Priority Rules
The Cahn-Ingold-Prelog (CIP) priority rules are a set of guidelines used to assign priorities to substituents attached to a stereocenter in order to determine the configuration of chiral centers. By evaluating the atomic number and connectivity of the substituents, chemists can classify the configuration as either R (rectus) or S (sinister), which is vital for accurately describing the stereochemistry of organic compounds.
Related Practice
Textbook Question
The reaction of (R)-1-iodo-2-methylbutane with hydroxide ion forms an alcohol without breaking any bonds to the asymmetric center. The alcohol rotates the plane of polarization of plane-polarized light counterclockwise. What is the configuration of (+)-2-methyl-1-butanol?
Textbook Question
What is the configuration of the following compounds? (Use the given structures to answer the question.)
c. ()-lactic acid
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Textbook Question
The observed rotation of 2.0 g of a compound in 50 mL of solution in a polarimeter tube 20 cm long is +138°. What is the specific rotation of the compound?
Textbook Question
Convert the Fischer projection to a perspective formula.
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Textbook Question
Draw a perspective formula for each of the following:
a. (S)-2-chlorobutane
b. (R)-1,2-dibromobutane
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