Textbook Question
Draw the products of the following reactions. If the products can exist as stereoisomers show what stereoisomers are formed.
g. 3,3-dimethyl-1-pentene + HBr
10. Addition Reactions
Hydrohalogenation
3:37 minutesProblem 6
Textbook Question
What is the major product obtained from the reaction of HBr with each of the following?a. 
Verified step by step guidance1
Step 1: Identify the type of reaction. The reaction involves HBr, which is a hydrohalogenation reaction. This means the addition of HBr across the double bond in the alkene structure.
Step 2: Apply Markovnikov's rule. In hydrohalogenation, the hydrogen atom (H) from HBr will add to the carbon of the double bond that has more hydrogen atoms, while the bromine atom (Br) will add to the carbon with fewer hydrogen atoms.
Step 3: Analyze the structure of the alkene. The double bond is located between two carbons in the cyclohexane ring. One of these carbons is bonded to two hydrogens, while the other is bonded to one hydrogen. According to Markovnikov's rule, the hydrogen will add to the carbon with two hydrogens, and bromine will add to the carbon with one hydrogen.
Step 4: Draw the intermediate carbocation. After the hydrogen adds to the carbon with more hydrogens, a carbocation forms on the carbon with fewer hydrogens. This carbocation is stable because it is part of a cyclohexane ring.
Step 5: Complete the reaction by adding bromine to the carbocation. Bromine will bond to the positively charged carbon, resulting in the major product of the reaction.
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Video duration:
3mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electrophilic Addition
Electrophilic addition is a fundamental reaction mechanism in organic chemistry where an electrophile reacts with a nucleophile, typically involving alkenes or alkynes. In this case, HBr acts as the electrophile, adding across the double bond of cyclohexene. This process results in the formation of a more stable product, often following Markovnikov's rule, which states that the more substituted carbon will bond with the electrophile.
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Markovnikov's Rule
Markovnikov's rule is a principle that predicts the outcome of the addition of HX (like HBr) to alkenes. It states that when HX adds to an asymmetric alkene, the hydrogen atom will attach to the carbon with the greater number of hydrogen atoms already attached, while the halide (Br in this case) will attach to the more substituted carbon. This rule helps in determining the major product of the reaction.
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Stability of Carbocations
The stability of carbocations is crucial in determining the major product of electrophilic addition reactions. Carbocations are positively charged carbon species that can form during the reaction. More substituted carbocations (tertiary > secondary > primary) are more stable due to hyperconjugation and inductive effects. In the reaction of HBr with cyclohexene, the formation of a more stable carbocation intermediate will favor the product that results from this pathway.
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