Ch. 11 - Radical ReactionsSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

The presence of radicals in some familiar looking addition reactions can completely change the product. 

Concept #1: The general mechanism of Allylic Halogenation.  

Remember our friendly addition reaction halogenation? Notice that you achieve a vicinal dihalide in this reaction.  

Now we see this reaction. Note that the only difference is the presence of a radical initiator.

This one added condition will lead to the formation of a mixture of allylic alkyl halides. Here’s the full mechanism:

Concept #2: The products of Allylic Chlorination.

Concept #3: Mechanism of Allylic Bromination.

Predict the product(s) of the following reaction. 

Example #1: Predict the product(s) of the following reaction. 

Additional Problems
Complete the following reaction with the correct structures of the products. Don’t forget to specify the stereochemistry.
Upon treatment of 1-methylcyclopentene with NBS and irradiation with UV light, exactly nine compounds (including stereoisomers) are formed. Draw any four of the possible products.
The allylic bromination of the alkene below with NBS gives four different products. Draw the two initially formed free radical intermediates together with any applicable resonance structures and the four products.  
Predict the organic product of the following reaction. When appropriate, be sure to indicate stereochemistry. If more than one product is formed be sure to indicate the major product. Draw all answers in skeletal form.
Fill in the box with the product(s) that are missing from the chemical reaction equation. Draw only the predominant regioisomer product or products (i.e. Markovnikov or non-Markovnikov products) and please remember that you must draw the structures of all the product stereoisomers using wedges and dashes to indicate stereochemistry. When a racemic mixture is formed, you must write "racemic" under both structures EVEN THOUGH YOU DREW BOTH STRUCTURES.
Provide the mechanism of the propagation steps to explain the stereochemistry of the products (why Br can be added from both sides). Be sure to include all arrows, formal charges, radicals and intermediates if needed.
Write the structure(s) of the product(s) for the reaction below. Be sure to indicate any relevant stereochemistry. 
Write the products of the reactions of the compound shown in the center with the reagents shown on the arrows. Make sure to include stereochemistry, but do not write mechanisms. DON’T LET THE BICYCLIC STRUCTURE INTIMIDATE YOU: it is just an alcohol, and will react like any other alcohol.
Which one of the following is the major product of the reaction below?
Draw the product of the reaction.
When ethylbenzene is treated with NBS and irradiated with UV light, two stereoisomeric compounds are obtained in equal amounts. Draw the products and explain why they are obtained in equal amounts: Selective bromination at the benzylic position generates a ____________ that gives rise to a racemic mixture.
What is the major product of the following reaction?
What are the possible products of the reaction below? Check all that would form in significant quantities. 
Predict the products of the following reaction.   
Draw the structure of the major product formed in the following reaction of p-cymene with N-bromosuccinimide under the conditions shown. The molecular formula of the product is given.  
Provide the structure of the major product(s) for the following reaction. 
Draw the major product of the following reactions.
Provide the structure of the major product(s) for the following reaction. 
In principle, how many products (structural isomers, not stereoisomers) are possible from the monobromination of 1 - methylcyclohexene with NBS?a. 2b. 3c. 5d. 7  
Which of the following alkenes undergoes allylic bromination to form a single monobrominated product?
NBS bromination of cyclohexa-1, 4-diene yields 2 products. Draw them.