Interpretation:
By drawing the resonance structures of the carbocation intermediates, among the two
Concept introduction:
The mechanism of addition of HBr to alkenes involves the formation of a more stable carbocation which is attacked by the Br- ion in the second step. Electron releasing groups in the
To predict:
Knowing the mechanism of HBr addition to alkenes and having an idea about the effects of various substituent groups on aromatic substitution, which of the two alkenes shown will react faster with HBr.
To explain:
The answer given by drawing the resonance structures of the carbocation intermediates.
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Organic Chemistry
- Draw a structural formula for the major product of the reaction shown.arrow_forwardN,N-diethyl-m-toluamide (DEET) is the active ingredient in many insect repellent preparations. Following is one of the steps in its synthesis. In the box below draw the structure of the product of this reaction. H3C MgBr 1. CO2 2. H3O+ product • You do not have to consider stereochemistry. • You do not have to explicitly draw H atoms. • Do not include lone pairs in your answer. They will not be considered in the grading. • Draw the Grignard reagent as a covalent magnesium bromide. 90-87 0 + 11 ? n [arrow_forwardDraw the structures of two alkenes that would react to form the haloalkane below upon addition of HBr. Your alkenes should be different regioisomers that yield the haloalkane as the major product without requiring rearrangement to occur.arrow_forward
- There is great excess of H2O in this reaction.arrow_forward1. Reaction of 2,3-dimethyl-1-butene with HBr leads to an alkyl bromide, C6H13Br. On treatment of this alkyl halide with KOH in methanol, elimination of HBr occurs and a hydrocarbon that is isometric with the starting alkene is formed. What is the structure of this hydrocarbon and how do you think it is formed from an alkyl bromide? 2. 1-Octen-3-ol is a potent mosquito attractant commonly used in mosquito traps. A number of reactions, including hydrogenation, will transform 1-Octen-3-ol into a less effective molecule. Write a complete reaction equation for the hydrogenation of this alkenol.arrow_forwarddraw the two possible carbocations that can form when this alkene reacts with a strong acid (such as HBr or H3O+). of the two structures you drew, circle the more stable carbocationarrow_forward
- N,N-diethyl-m-toluamide (DEET) is the active ingredient in many insect repellent preparations. Following is one of the steps in its synthesis. In the box below draw the structure of the product of this reaction. H3C MgBr 1. CO₂ 2. H₂O* product • You do not have to consider stereochemistry. • You do not have to explicitly draw H atoms. • Do not include lone pairs in your answer. They will not be considered in the grading. • Draw the Grignard reagent as a covalent magnesium bromide.arrow_forwardWhen propene reacts with gaseous hydrogen bromide, HBr, two products, 1-bromopropane and 2-bromopropane are formed. The reaction is a two-step process in which the electrophilic attack occurs in the first step. Identify the electrophile in this reaction Draw a diagram showing the first step of the reaction that leads to the production of 2-bromopropane.arrow_forwardEthane reacts with chlorine (Cl2) in the presence of ultra-violet (UV) light, to produce 1-chloropropane (CH3CH2Cl) and hydrogen bromide (HCl). As shown in the equation below. CH3CH3 + Cl2 → CH3CH2Cl + HCl Describe the reaction mechanism of the reaction between ethane and chlorine to produce 1-chloroethane. The description should be detailed and must include the type of bond fission that takes place. You may sketch and insert suitable diagrams to aid your description if you wish. Would this reaction (question 34(c)) give a high yield of 1-chloroethanearrow_forward
- Ethane reacts with chlorine (Cl2) in the presence of ultra-violet (UV) light, to produce 1-chloropropane (CH3CH2Cl) and hydrogen bromide (HCl). As shown in the equation below. CH3CH3 + Cl2 → CH3CH2Cl + HCl Describe the reaction mechanism of the reaction between ethane and chlorine to produce 1-chloroethane. The description should be detailed and must include the type of bond fission that takes placearrow_forwardEthane reacts with chlorine (Cl2) in the presence of ultra-violet (UV) light, to produce 1-chloropropane (CH3CH2Cl) and hydrogen bromide (HCl). As shown in the equation below. CH3CH3 + Cl2 → CH3CH2Cl + HCl Describe the reaction mechanism of the reaction between ethane and chlorine to produce 1-chloroethane. The description should be detailed and must include the type of bond fission that takes place. You may sketch and insert suitable diagrams to aid your description if you wish.arrow_forwardH3C CH3 H3C NA C→XT Br Br₂ CH₂Cl₂ H3C Electrophilic addition of bromine, Br₂, to alkenes yields a 1,2-dibromoalkane. The reaction proceeds through a cyclic intermediate known as a bromonium ion. The reaction occurs in an anhydrous solvent such as CH₂Cl₂. CH3 Br In the second step of the reaction, bromide is the nucleophile and attacks at one of the carbons of the bromonium ion to yield the product. Due to steric clashes, the bromide ion always attacks the carbon from the opposite face of the bromonium ion so that a product with anti stereochemistry is formed. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions Br CH3 H3C CH3arrow_forward
- Macroscale and Microscale Organic ExperimentsChemistryISBN:9781305577190Author:Kenneth L. Williamson, Katherine M. MastersPublisher:Brooks Cole