Concept explainers
a)
Interpretation:
The most reactive compound in an electrophilic
Concept Introduction:
Effect of an electron withdrawing or an electron releasing group:
The electron withdrawing or electron releasing groups have significance role in the activation and deactivation of benzene rings during an electrophilic aromatic substitution reaction. An electron withdrawing group deactivates the benzene rings by reducing the electron density on the rings. The electrophilic groups have the tendency to accept or withdraw the electrons from the rest of compound. The deactivating groups are those groups that tend to withdraw the electron density from the benzene ring and decrease the overall rate of reactions.
Rule: The rate of reactions in aromatic electrophilic substitution reactions rely upon the presence of an electron releasing or an electron withdrawing group.
b)
Interpretation:
The least reactive compound in an electrophilic aromatic substitution reaction for each row of substituted benzenes has to be predicted.
Concept Introduction:
Effect of an electron withdrawing or an electron releasing group:
The electron withdrawing or electron releasing groups have significance role in the activation and deactivation of benzene rings during an electrophilic aromatic substitution reaction. An electron withdrawing group deactivates the benzene rings by reducing the electron density on the rings. The electrophilic groups have the tendency to accept or withdraw the electrons from the rest of compound. The deactivating groups are those groups that tend to withdraw the electron density from the benzene ring and decrease the overall rate of reactions.
Rule: The rate of reactions in aromatic electrophilic substitution reactions rely upon the presence of an electron releasing or an electron withdrawing group.
c)
Interpretation:
The compound that yields the highest percentage of a meta product in an electrophilic aromatic substitution reaction for each horizontal row of substituted benzenes has to be stated.
Concept Introduction:
Effect of an electron withdrawing or an electron releasing group:
The electron withdrawing or electron releasing groups have significance role in the activation and deactivation of benzene rings during an electrophilic aromatic substitution reaction. An electron withdrawing group deactivates the benzene rings by reducing the electron density on the rings. The electrophilic groups have the tendency to accept or withdraw the electrons from the rest of compound. The deactivating groups are those groups that tend to withdraw the electron density from the benzene ring and decrease the overall rate of reactions.
Rule: The rate of reactions in aromatic electrophilic substitution reactions rely upon the presence of an electron releasing or an electron withdrawing group.
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Organic Chemistry (8th Edition)
- What is the rate-determining step in the mechanism of an electrophilic substitution reaction of benzene? Select one: OA. Attachment of the electrophile to benzene ring. OB. Bonding of catalyst to electrophile precursor. O C. Reformation of acid catalyst. OD. Formation of the electrophile. OE. Loss of H+ ion form arenium ion intermediate to reform aromatic ring.arrow_forwardWhat is the rate-determining step in an electrophilic substitution of benzene? Select one: O A. Loss of an H* ion from the arenium carbocation to reform the aromatic ring. O B. Attachment of the electrophile to the benzene ring. O C. O D. The step that generates the electrophile. regeneration of the reaction catalyst.arrow_forwardWhat is the driving force for losing a proton as the last step in electrophilic aromatic substitution? Select one: O A. To make room for the electrophile. O B. To make the ring more reactive. OC. To reform an aromatic system. O D. To neutralize the base that is present.arrow_forward
- 2. A benzene ring alters the reactivity of a neighboring group in the so-called "benzylic" position, similarly to how a double bond alters the reactivity of groups in the "allylic" position. R .R allylic position benzylic position Benzylic cations, anions, and radicals are all more stable than simple alkyl intermediates. a) Use resonance structures to show the delocalization of the positive charge, negative charge, and unpaired electron of the benzyl cation, anion, and radical.arrow_forwardWhich is/are NOT TRUE about bimolecular nucleophilic substitution reactions? Select one or more: 1. A carbocation intermediate is formed. 2. A strong nucleophile displaces a halogen atom in a concerted mechanism. 3. Presence of polar aprotic solvents promotes this reaction. 4. Methyl halides react faster than secondary alkyl halides.arrow_forward6. Circle the structure with the most nucleophilic double bond. Put a box around the structure with the least nucleophilic double bond. OHarrow_forward
- For each reaction, write the letter corresponding to the type of reaction (before the number) and draw the MAJOR product (in the product side). A. Nucleophilic Addition B. Nucleophilic Condensation C. Nucleophilic Acyl Substitutionarrow_forward4. Circle the electrophilic and nucleophilic atoms in each substitution reaction below. Provide the neutral organic product; where a stereocenter is created, use a wavy bond to indicate a mixture of configurations or wedges/dashes for stereospecific reactions. Also, provide the dominant reaction mechanism (Sn2 or SN1) somewhere in each box. A. Br NaSEt DMF В. ELOH C. .SO2NHNA Cl + D. NaH Br- HO, DMFarrow_forwardWhat is the importance of proton transfer in the formation of ester? A.The carbonyl carbon is easily attacked by the nucleophile. B. The oxygen that has been attached to the two alkyl groups will become stable. C. The removal of a bulky substituent attached to the reactive site stabilizes the compound. D. none of the abovearrow_forward
- 4) Vocabulary: words are given circle the correct one. a. A Robinson Annulation can occur with acetoacetate / malonic ester / both / neither Fill in the blanks with the appropriate vocabulary word. If two as the nucleophile, and with conjugated ester / conjugated ketone / epoxide / all/ none as the electrophile. The Robinson Annulation is a reaction followed by a reaction and always / sometimes / never gives a 6-member ring. b. It is always / sometimes / never possible to use base to form an acyl anion directly from an aldehyde. c. True / False.Aliphatic heterocycles typically react like linear versions of the functional group. d. Claisen condensations require catalytic / 1 equivalent / large excess base, at least 2 alpha hydrogens on the nucleophile, always / sometimes / never use an ester as an electrophile, and always / sometimes / never use an ester as a nucleophile. e. Reaction of a beta-ketoester with water, acid, and heat gives first a reaction, then and lastly This reaction…arrow_forwardAnswer each question thoroughly nd completely. 1. Thoroughly explain why a halogen, X2 ,cannot be directly added to a benzene ring. 2. What properties does a benzene ring have that allude to its reactivity? 3. What is meant by aliphatic? 4. Explain the different types of oxidations for phenols. Give an example of each with the name of the phenol, and the oxidized phenol product. The examples should be drawn in chemical reaction form. 5. Are phenols reactive? Why or why not? 6. What is meant by an ortho director? Use a reaction as an example. 7. Why is the rate limiting step important in the bromination of benzene? 8. What role does the sigma complex play in electrophilic aromatic substitution reactions? 9. How do Lewis acids play a role in generation of the electrophile? A mechanism will be needed to go along with your explanation. 10. Explain the nitration of benzene reaction. 11. What are deactivating groups, and how do they relate to substitution on the benzene ring? 12. What is the…arrow_forwardSpecify the reaction conditions to favour the indicated elimination mechanism. a. Strong base, such as hydroxide, an alkoxide, or equivalent b. Water or alcohol or equivalent weak base with heat c. Weak acid, such as formic acid, or equivalent d. Strong base, such as hydroxide, an alkoxide, or equivalentarrow_forward
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