Textbook Question
Based on the absolute configuration of (S)-butan-2-ol, what can you say about the direction it rotates plane-polarized light?
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Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
Chapter 5, Problem 27a
Naproxen is a commercially available anti-inflammatory sold under the name Aleve.
(a) Assign the absolute configuration as R or S.
Verified step by step guidance1
Identify the chiral center in the Naproxen molecule. A chiral center is a carbon atom bonded to four different groups.
Assign priorities to the four groups attached to the chiral center based on the Cahn-Ingold-Prelog (CIP) priority rules. These rules prioritize groups based on the atomic number of the atoms directly attached to the chiral center. If two atoms are the same, move outward along the chain until a difference is found.
Orient the molecule so that the group with the lowest priority (priority 4) is pointing away from you (into the plane of the paper or screen).
Determine the order of the remaining three groups (priority 1, 2, and 3) as you look at the molecule. Trace a path from priority 1 to 2 to 3. If the path is clockwise, the configuration is R (rectus). If the path is counterclockwise, the configuration is S (sinister).
Verify your assignment by double-checking the priority order and the orientation of the lowest-priority group to ensure the configuration is correctly assigned as either R or S.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Chirality
Chirality refers to the geometric property of a molecule that makes it non-superimposable on its mirror image, much like left and right hands. Molecules that possess chirality typically have a carbon atom bonded to four different substituents, leading to two distinct configurations known as enantiomers. Understanding chirality is essential for determining the absolute configuration of compounds like Naproxen.
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What is chirality?
Cahn-Ingold-Prelog Priority Rules
The Cahn-Ingold-Prelog (CIP) priority rules are a set of guidelines used to assign 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 is crucial for determining whether the configuration around a chiral center is R (rectus) or S (sinister).
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R and S Configuration
The R and S configuration system is used to describe the absolute configuration of chiral centers in molecules. If the highest priority substituent is positioned clockwise when viewed from a specific perspective, the configuration is designated as R. Conversely, if the highest priority substituent is counterclockwise, it is designated as S. This system is vital for accurately describing the stereochemistry of compounds like Naproxen.
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Related Practice
Textbook Question
Prioritize the substituents at each chiral center and then, by each of the two methods discussed in Section 6.3.2.4, determine the absolute configuration. [Do not use your models, except to check your answers.]
(d)
Textbook Question
A student wanted to measure the specific rotation of the following propionate derivative (density = 1.12 g/ml).
A sample of the pure compound was placed in a 10.0-cm polarimeter tube, and using the sodium D line, the observed rotation at 20°C was determined to be +46.6° . What is the specific rotation of the propionate derivative?
Textbook Question
Naproxen is a commercially available anti-inflammatory sold under the name Aleve.
(b) Given that naproxen rotates plane-polarized light in the clockwise direction, should it be referred to as (d) or (l)?
(c) Is it (+) or (-)?
(d) What direction (d or l; + or −) would you expect the enantiomer of naproxen to rotate plane-polarized light?
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Textbook Question
Prioritize the substituents at each chiral center and then, by each of the two methods discussed in Section 6.3.2.4, determine the absolute configuration. [Do not use your models, except to check your answers.]
(h)
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Textbook Question
(R)-Limonene is a cyclic terpene responsible for the smell of oranges and other citrus fruits.
(a) Given that (R)-limonene rotates plane-polarized light in the clockwise direction, should it be referred to as (d) or (l)?
(b) Is it (+) or (-)?
(c) What direction (d or l; + or −) would you expect (S)-limonene to rotate plane-polarized light?
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