Concept explainers
Interpretation:
Given that the substitution reaction of toluene with Br2 can, in principle, lead to the formation of three isomeric bromotoluene products. In practice, however, only o- and p-bromotoluene are formed in substantial amounts. The meta isomer is not formed. The structures of three possible carbocation intermediates are to be drawn and the predominance of ortho and para products over the meta product is to be explained.
Concept introduction:
When a monosubstituted benzene is subjected to electrophilic substitution reaction, the electrophile in principle can get substituted in any of the three positions, ortho, meta and para. Which isomer will be formed predominantly depends on the stability of the allylic intermediate formed by the attack of the electrophile on the benzene ring. The more stable intermediate will yield the products.
To draw:
The structures of three possible carbocation intermediates formed during the substitution reaction of toluene that leads to the formation of o-, p- and m-bromotoluenes.
To explain:
The observation when toluene reacts with bromine the ortho and para products are formed predominantly than the meta product.
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Chapter 15 Solutions
ORGANIC CHEMISTRY-EBOOK>I<
- b) Listed below are several hypothetical nucleophilic substitution reactions. None is synthetically useful because the product indicated is not formed at an appreciable rate. In each case provide an explanation for the failure of the reaction to take place as indicated. OMe HO + OMe + OH HO + CH; OHarrow_forwardReaction of but-1-ene with HBr gives two products in unequal amounts. In each case, identify the two products, state which is the major product, explain why it is the major product and give the mechanism for its formation.arrow_forwardmethanol + CH3OH Suppose you were told that the above reaction was a substitution reaction but you were not told the mechanism. Evaluate the following categories to determine the reaction mechanism and then draw the structure of the major organic product. Type of alkyl halide: Type of nucleophile: Solvent: Is the product racemic?arrow_forward
- Provide the structure(s) of the expected major organic product of the reaction shown. 1) Disiamylborane 2) H₂O₂, NaOH OI O II ||| O IV OV CH3CH₂C(CH3)2C=CH OH OH xx xo IVarrow_forwardIf phenoxide ion is allowed to react with 1-bromopentane, pentyl phenyl ether is obtained. However, if cyclohexane is used as the alkyl halide, the major products are phenol and cyclohexene. Explain how these products were formed.arrow_forwardBr Brz CH3 CH3 H3C CH2CI2 H3C Br 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 CH,Cl). 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: :Br: .CH3 H3C H3C CH3 Br:arrow_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+ HClDescribe 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_forwardAlcohols are important for organic synthesis, especially in situations involving alkenes. The alcohol might be the desired product, or the OH group might be transformed into another functional group via halogenation, oxidation, or perhaps conversion to a sulfonic ester derivative. Formation of an alcohol from an alkene is particularly powerful because conditions can be chosen to produce either the Markovnikov or non-Markovnikov product from an unsymmetrical alkene. Using your reaction roadmap as a guide, show how to convert 4-methyl-1-pentene into 5-methylhexanenitrile. You must use 4-methyl-1-pentene and sodium cyanide as the source of all carbon atoms in the target molecule. Show all reagents needed and all molecules synthesized along the way.arrow_forwardWrite a mechanism that accounts for the formation of ethyl isopropyl ether as one of the products in the following reaction. CI OEt HCI EtOH Write the mechanism for step one of this reaction. Show lone pairs and formal charges. Only the acidic hydrogen should be drawn out with a covalent bond. Write the mechanism for step two of this reaction (where the product of step one reacts with the solvent, ethanol). Show lone pairs and formal charges. Only the acidic hydrogen should be drawn out with a covalent bond. Write the mechanism for the last step of this reaction (formation of ethyl isopropyl ether). Show lone pairs and formal charges. Only the acidic hydrogen should be drawn out with a covalent bond. CI will act as the base in this reaction.arrow_forward
- provide the hydrotreating for the organic compoud C9H7N in a more detailed way? regarding which bond will break first and how many steps the reactant will go through to reach the product shown.arrow_forwardWhen 2-iodo-1,4-dimethylcyclohexane is heated in acetic acid, CH3COOH, a mixture of substitution and elimination products is obtained. Provide structures for all possible products, writing [not drawing] the name of the mechanism by which each one is formed.arrow_forwardWhen the given reactions below are done once, which of the following reactions is used to prepare dihalogenated alkyl halides as major products? Select one: O Reaction of ethane with Cl₂ in the presence of light Reaction of ethene with HBr Reaction of ethyne with two moles of HCI Reaction of ethene with Br₂ in H₂Oarrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning