Textbook Question
Predict the product of the following benzylic bromination reactions.
(c)
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Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions
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
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Mullins 1st EditionCh. 11 - Properties and Synthesis of Alkyl Halides: Radical ReactionsProblem 63a
Mullins 1st EditionCh. 11 - Properties and Synthesis of Alkyl Halides: Radical ReactionsProblem 63aChapter 10, Problem 63a
Predict the product of the following benzylic bromination reactions.
(a) 
Verified step by step guidance1
Identify the benzylic position in the given molecule. The benzylic position is the carbon atom directly attached to the benzene ring, which in this case is the carbon atom adjacent to the triple bond.
Understand that benzylic bromination typically involves the substitution of a hydrogen atom at the benzylic position with a bromine atom. This is due to the stability of the benzylic radical formed during the reaction.
Consider the reagents typically used for benzylic bromination, such as N-bromosuccinimide (NBS) in the presence of light or heat, which facilitates the formation of bromine radicals.
Predict the product by replacing the hydrogen atom at the benzylic position with a bromine atom. This involves breaking the C-H bond and forming a new C-Br bond at the benzylic position.
Ensure that the stereochemistry of the molecule is maintained, as benzylic bromination does not typically affect the stereochemistry of the rest of the molecule.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Benzylic Bromination
Benzylic bromination involves the selective substitution of a hydrogen atom at the benzylic position with a bromine atom, typically using N-bromosuccinimide (NBS) as the brominating agent. This reaction is favored due to the stability of the benzylic radical formed during the process, which is stabilized by resonance with the aromatic ring.
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Mechanism of Allylic Bromination.
Radical Stability
Radical stability is crucial in benzylic bromination, as the reaction proceeds through a radical intermediate. Benzylic radicals are particularly stable due to resonance stabilization, where the unpaired electron can delocalize over the aromatic ring, reducing the energy of the radical and making the reaction more favorable.
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03:43The radical stability trend.
Resonance
Resonance in organic chemistry refers to the delocalization of electrons across adjacent atoms, which can stabilize intermediates like radicals. In benzylic bromination, the benzylic radical benefits from resonance with the aromatic ring, allowing the electron density to be spread over multiple atoms, thus stabilizing the radical and facilitating the reaction.
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Related Practice
Textbook Question
Predict the product of the following benzylic bromination reactions.
(b)
Textbook Question
A halogenation intended to make compound A formed B instead.
(c) Given the two mechanisms you drew, why might B have formed selectively?
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Textbook Question
The human body can excrete drugs and other exogenous molecules by converting them into polar, water-soluble compounds by a reaction similar to the autoxidation described in Section 11.6. Why are the following drug candidate molecules susceptible to oxidation by this pathway?
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Textbook Question
A halogenation intended to make compound A formed B instead.
(d) Without looking it up, would you expect C–Ha or C–Hb to have the lower bond-dissociation energy?
Textbook Question
A halogenation intended to make compound A formed B instead.
(b) Suggest a mechanism that rationalizes the formation of B.
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