a. Predict the relative pKa values of cyclopentadiene and

Which of the following have delocalized electrons?

a. Draw resonance contributors for the following species, showing all the lone pairs: 1. CH 2 N 2 2. N 2 O 3. NO- 2 b. For each species, indicate the most stable resonance contributor.

What is the major product of each of the following reactions? Assume that there is an equivalent amount of each reagent.

Draw resonance contributors for the following ions:

Draw all the products of the following reaction:

Are the following pairs of structures resonance contributors or different compounds?

a. How many linear dienes have molecular formula C 6 H 10 ? (Disregard cistrans isomers.) b. How many of the linear dienes in part a are conjugated dienes? c. How many are isolated dienes?

a. Draw resonance contributors for the following species. Do not include structures that are so unstable that their contributions to the resonance hybrid would be negligible. Indicate which are major contributors and which are minor contributors to the resonance hybrid. b. Do any of the species have resonance contributors that all contribute equally to the resonance hybrid?

Which ion in each of the following pairs is more stable and why?

Which compound would you expect to have the greater heat of hydrogenation, 1,2-pentadiene or 1,4- pentadiene?

Which resonance contributor in each pair makes the greater contribution to the resonance hybrid?

Classify the following species as aromatic, nonaromatic, or antiaromatic:

a. Which oxygen atom has the greater electron density?

Which compound is the strongest base?

Which can lose a proton more readily, a methyl group bonded to cyclohexane or a methyl group bonded to benzene?

The triphenylmethyl cation is so stable that a salt such as triphenylmethyl chloride can be isolated and stored. Why is this carbocation so stable?

a. The B ring (Section 3.15) of cortisone, a steroid, is formed by a Diels–Alder reaction using the two reactants shown here. What is the product of this reaction? b. The C ring of estrone (a steroid) is formed by a Diels–Alder reaction using the two reactants shown here. What is the product of this reaction?

Answer the following questions and explain the reason for each answer:

Answer the following questions and explain the reason for each answer:

Rank the following compounds in order from most stable to least stable:

Which species in each pair is more stable?

Which species in each of the pairs in Problem 77 is the stronger base?

Purine is a heterocyclic compound with four nitrogen atoms. a. Which nitrogen is most apt to be protonated? b. Which nitrogen is least apt to be protonated?

Which of the following compounds is the strongest acid?

Why is the delocalization energy of pyrrole (21 kcal/mol) greater than that of furan (16 kcal/mol)?

Rank the indicated hydrogen in the following compounds in order from most acidic to least acidic:

Answer the following questions for the p molecular orbitals (MOs) of 1,3,5,7-octatetraene: a. How many MOs does the compound have? b. Which are the bonding MOs and which are the antibonding MOs? c. Which MOs are symmetric and which are antisymmetric? d. Which MO is the HOMO and which is the LUMO in the ground state? e. Which MO is the HOMO and which is the LUMO in the excited state? f. What is the relationship between HOMO and LUMO and symmetric and antisymmetric orbitals? g. How many nodes does the highest-energy MO of 1,3,5,7-octatetraene have between the nuclei?

How could you synthesize the following compound from starting materials containing no more than six carbons? ( Hint: A 1,6-diketone can be synthesized by oxidative cleavage of a 1,2-disubstituted cyclohexene.)

A student obtained two products from the reaction of 1,3-cyclohexadiene with Br2 (disregarding stereoisomers). His lab partner was surprised when he obtained only one product from the reaction of 1,3-cyclohexadiene with HBr (disregarding stereoisomers). Account for these results.

How could the following compounds be synthesized using a DielsAlder reaction?

a. How could each of the following compounds be prepared from a hydrocarbon in a single step?

Draw the products obtained from the reaction of 1 equiv HBr with 1 equiv 1,3,5-hexatriene. a. Which product(s) will predominate if the reaction is under kinetic control? b. Which product(s) will predominate if the reaction is under thermodynamic control?

How would the following substituents affect the rate of a DielsAlder reaction? a. an electron-donating substituent in the diene b. an electron-donating substituent in the dienophile c. an electron- withdrawing substituent in the diene

Draw the major products obtained from the reaction of one equivalent of HCl with the following compounds. For each reaction, i ndicate the kinetic and thermodynamic products. a. 2,3-dimethyl-1,3- pentadiene b. 2,4-dimethyl-1,3-pentadiene

The acid dissociation constant ( Ka ) for loss of a proton from cyclohexanol is 1 * 10-16 . a. Draw an energy diagram for loss of a proton from cyclohexanol. Ka = 1 1016 H + OH O + b. Draw the resonance contributors for phenol. c. Draw the resonance contributors for the phenolate ion. d. On the same plot with the energy diagram for loss of a proton from cyclohexanol, draw an energy diagram for loss of a proton from phenol. H + OH O + e. Which has a greater Ka , cyclohexanol or phenol? f. Which is a stronger acid, cyclohexanol or phenol?

Protonated cyclohexylamine has a Ka = 1 * 10-11 . Using the same sequence of steps as in Problem 91 , determine which is a stronger base, cyclohexylamine or aniline.

Draw the product or products that would be obtained from each of the following reactions:

What two sets of a conjugated diene and a dienophile could be used to prepare the following compound?

a. Which dienophile in each pair is more reactive in a DielsAlder reaction? O 1. CH2 CHCH or 2. O CH2 CHCH2CH O CH2 CHCH or CH2 CHCH3 b. Which diene is more reactive in a DielsAlder reaction? CH2 CHCH or CHOCH3 CH2 CHCH CHCH2OCH3

Cyclopentadiene can react with itself in a DielsAlder reaction. Draw the endo and exo products.

Which diene and which dienophile could be used to prepare each of the following?

a. Propose a mechanism for the following reaction:

a. What are the products of the following reaction? Br + 2 b. How many stereoisomers of each product could be obtained?

As many as 18 different DielsAlder products can be obtained by heating a mixture of 1,3-butadiene and 2-methyl-1,3-butadiene. Identify the products.

As many as 18 different DielsAlder products can be obtained by heating a mixture of 1,3-butadiene and 2-methyl-1,3-butadiene. Identify the products.

While attempting to recrystallize maleic anhydride, a student dissolved it in freshly distilled cyclopentadiene rather than in freshly distilled cyclopentane. Was his recrystallization successful?

The following equilibrium is driven to the right if the reaction is carried out in the presence of maleic anhydride (see Problem 102 ). What is the function of maleic anhydride?

In 1935, J. Bredt, a German chemist, proposed that a bicycloalkene could not have a double bond at a bridgehead carbon unless one of the rings contains at least eight carbons. This is known as Bredts rule. Explain why there cannot be a double bond at this position.

The experiment shown next and discussed in Section 8.18 shows that the proximity of the chloride ion to C-2 in the transition state causes the 1,2-addition product to be formed faster than the 1,4-addition product. CH2 CHCH CHCH3 DCl CHCH CH2CHCH CH 3 2CH CHCHCH3 D Cl D Cl 78 C + + a. Why was it important for the investigators to know that the preceding reaction was being carried out under kinetic control? b. How could the investigators know that the reaction was being carried out under kinetic control?

The product of the following reaction has a fused bicyclic ring. What is its structure?

Draw the resonance contributors of the cyclooctatrienyl dianion. a. Which of the resonance contributors is the least stable? b. Which of the resonance contributors makes the smallest contribution to the hybrid?

Investigation has shown that cyclobutadiene is actually a rectangular molecule rather than a square molecule, and that there are two different 1,2-dideuterio-1,3-cyclobutadienes. Explain the reason for these unexpected observations.

Problem 6P a. Predict the relative bond lengths of the three carbon-oxygen bonds in CO32? ________________ b. What would you expect the charge to be on each oxygen atom?

Which species in each pair is more stable?

Which of the following species has the greatest delocalization energy?

Problem 18P a. Predict the relative pKa values of cyclopentadiene and cycloheptatriene. b. Predict the relative pKa values of cyclopropene and cyclopropane.

Problem 19E Which is more soluble in water, 3-bromocyclopropene or bromocyclopropane?

Which of the compounds in Problem \(12\) are antiaromatic? Equation Transcription: Text Transcription: 12

Which member of each pair is the stronger acid?

Problem 31P Which is a stronger base? a. ethylamine or aniline b. ethylamine or ethoxide ion (CH3CH20?) c. phenolate ion or ethoxide ion

Rank the following compounds in order from strongest acid to weakest acid:

a. Why does deuterium add to \(C-1\) rather than to \(C-4\) in the preceding reaction? b. Why was \(D C I\) rather than \(H C I\) used in the reaction? Equation Transcription: Text Transcription: C-1 C-4 DCI HCI

Problem 44P A student wanted to know whether the greater proximity of the nucleophile to the C-2 carbon in the transition state is what causes the 1,2-addition product to be formed faster when 1,3- butadiene reacts with HCl. Therefore, she decided to investigate the reaction of 2-methyl- 1,3-cyclohexadiene with HCl. Her friend told her that she should use 1-methyl-1,3-cyclohexadiene instead. Should she follow her friend’s advice?

Problem 45P a. When HBr adds to a conjugated diene, what is the rate-determining step? b. When HBr adds to a conjugated diene, what is the product-determining step?

Problem 9P a. What is the value of n in Hückel’s rule when a compound has nine pairs of p electrons? b. Is such a compound aromatic?

Problem 21P How many bonding, nonbonding, and antibonding ? molecular orbitals does cyclobutadiene have? In which molecular orbitals are the ? electrons?

Problem 22P Can a radical be aromatic?

Which compound in each set is aromatic? Explain your choice.

Problem 11P The pKa of cyclopentane is > 60, which is about what is expected for a hydrogen that is bonded to an sp3 carbon. Explain why cyclopentadiene is a much stronger acid (pKa of 15), even though it too involves the loss of a proton from an sp3 carbon.

Problem 23P Following the instructions for drawing the ? molecular orbital energy levels of the compounds shown in Figure 8.8 , draw the ? molecular orbital energy levels for the cycloheptatrienyl cation, the cycloheptatrienyl anion, and the cyclopropenyl cation. For each compound, show the distribution of the ? electrons. Which of the compounds are aromatic? Which are antiaromatic?

A methoxy substituent attached to a benzene ring withdraws electrons inductively (through the \(\sigma\) bonds) because oxygen is more electronegative than carbon. The group also donates electrons through the \(\pi\) bonds—this is called resonance electron donation. From the \(p K_{a}\) values of the unsubstituted and methoxy-substituted carboxylic acids, predict whether inductive electron withdrawal or resonance electron donation is a more impor-tant effect for a \(\mathrm{CH}_{3} \mathrm{O}^{-}\) group. Equation Transcription: Text Transcription: sigma pi pK_a CH_3 O^-

What is the major product obtained from the addition of \(H B r\) to the following compound? Equation Transcription: Text Transcription: HBr

Predict the sites on each of the following compounds where protonation can occur. a. \(\mathrm{CH}_{3} \mathrm{CH} \equiv \mathrm{CHOCH}_{3}+\mathrm{H}^{+}\) Equation Transcription: ? Text Transcription: CH_3 CH trigram CHOCH_3 + H^+

What are the major \(1,2-\text { and } 1,4-\) addition products of the following reactions? For each reaction, indicate the kinetic and the thermodynamic products. Equation Transcription: Text Transcription: 1, 2- and 1, 4-

Identify the kinetic and thermodynamic products of the following reaction:

What are the products of the following reactions?

a. The following compounds have the same molecular formula as benzene. How many monosubstituted products would each have? 1. \(\mathrm{HC} \equiv \mathrm{CC} \equiv \mathrm{CCH}_{2} \mathrm{CH}_{3}\) 2. \(\mathrm{CH}_{2} \equiv \mathrm{CHC} \equiv \mathrm{CCH} \equiv \mathrm{CH}_{2}\) b. How many disubstituted products would each of the preceding compounds have? (Do not include stereoisomers.) c. How many disubstituted products would each of the compounds have if stereoisomers are included? Equation Transcription: ?? ??? Text Transcription: HC trigram CC trigram CCH_2 CH_3 CH_2 trigram CHC trigram CCH trigram CH_2

Between \(1865\) and \(1890\), other possible structures were proposed for benzene such as those shown here. Considering what nineteenth-century chemists knew about benzene, which is a bet-ter proposal for benzene’s structure, Dewar benzene or Ladenburg benzene? Why? Equation Transcription: Text Transcription: 1865 1890

Which of the following are aromatic?

a. In what direction is the dipole moment in fulvene? Explain. b. In what direction is the dipole moment in calicene? Explain.

What orbital do the lone-pair electrons occupy in each of the following compounds?

Problem 24P The heat of hydrogenation of 2,3-pentadiene, a cumulated diene, is 70.5 kcal/mol. What are the relative stabilities of cumulated, conjugated, and isolated dienes?

Name the following dienes and rank them in order from most stable to least stable. (Alkyl groups stabilize dienes in the same way that they stabilize alkenes; Section \(6.13\).) Equation Transcription: Text Transcription: 6.13

Which carbocation in each pair is more stable? b. \(\mathrm{CH}_{3} \mathrm{OC}^{+} \mathrm{H}_{2} \text { or } \mathrm{CH}_{3} \mathrm{NHC}^{+} \mathrm{H}_{2}\) Equation Transcription: Text Transcription: CH_3 O over+C H_2 or CH_3 NH over+C H_2

What is the major product of each of the following reactions, assuming that one equivalent of each reagent is used in each reaction?

Which of the double bonds in zingiberene, the compound responsible for the aroma of ginger, is the most reactive in an electrophilic addition reaction with \(H B r\)? Equation Transcription: Text Transcription: HBr

What are the products of the following reactions, assuming that one equivalent of each reagent is used in each reaction?

What would be the major product if the methoxy substituent in the preceding reaction were bonded to C-2 of the diene rather than to C-1?

Problem 50P Write a general rule that can be used to predict the major product of a Diels–Alder reaction between an alkene with an electron-withdrawing substituent and a diene with a substituent that can donate electrons by resonance depending on the location of the substituent on the diene.

What two products are formed from each of the following reactions?

a. Which of the following compounds have delocalized electrons? 1. \(\mathrm{CH}_{2}=\mathrm{CHCH}_{2} \mathrm{CH}=\mathrm{CH}_{2}\) 2. \(\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CHCH}=\mathrm{CHCH}_{2}\) b. Draw the resonance contributors for the compounds that have delocalized electrons. Equation Transcription: Text Transcription: CH_2 = CHCH_2 CH = CH_2 CH_3 CH = CHCH = CHCH_2

Draw resonance contributors for each of the following species and rank them in order of decreasing contribution to the hybrid:

Draw the resonance hybrid for each of the species in Problem \(4\) Equation Transcription: Text Transcription: 4

Problem 15P What orbitals contain the electrons represented as lone pairs in the structures of quinoline, indole, imidazole, purine, and pyrimidine?

Which of the following compounds could be protonated without destroying its aromaticity?

Problem 17P Refer to the electrostatic potential maps on page 347 to answer the following questions: a. Why is the bottom part of the electrostatic potential map of pyrrole blue? b. Why is the bottom part of the electrostatic potential map of pyridine red? c. Why is the center of the electrostatic potential map of benzene more red than the center of the electrostatic potential map of pyridine?

What is the total number of nodes in the \(\psi_{3} \text { and } \psi_{4}\) \(\text { MOS }\) of \(1,3\)-butadiene? Equation Transcription: Text Transcription: psi_3 and psi_4 MOs 1, 3

Problem 28P Answer the following questions for the ? MOs of 1,3-butadiene: a. Which are ? bonding MOs and which are ?* antibonding MOs? b. Which MOs are symmetric and which are antisymmetric? c. Which MO is the HOMO and which is the LUMO in the ground state? d. Which MO is the HOMO and which is the LUMO in the excited state? e. What is the relationship between the HOMO and the LUMO and symmetric and antisymmetric orbitals?

The most stable \(M O\) of \(1,3,5\)-hexatriene and the most stable \(M O\) of benzene are shown here. Which compound is more stable? Why? Equation Transcription: Text Transcription: MO 1, 3, 5

What stereoisomers are obtained from the two reactions shown on the top of page \(367\)? ( Hint: Review Section \(6.15\) .) Equation Transcription: Text Transcription: 367 6.15

Problem 41P What products would be obtained from the reaction of 1,3,5-hexatriene with one equivalent of HBr? Disregard stereoisomers.

What are the products of the following reactions, assuming that one equivalent of each reagent is used in each reaction? Disregard stereoisomers.

Which of the following conjugated dienes would not react with a dienophile in a Diels–Alder reaction?

What are the products of the following reactions?

Explain why the following compounds are not optically active: a. the product obtained from the reaction of 1,3-butadiene with cis-1,2-dichloroethene b. the product obtained from the reaction of 1,3-butadiene with trans-1,2-dichloroethene

What diene and what dienophile should be used to synthesize the following?

Problem 57P Which of the following have delocalized electrons?

Problem 58P a. Draw resonance contributors for the following species, showing all the lone pairs: 1. CH2N2 2. N2O 3. NO2- b. For each species, indicate the most stable resonance contributor.

What is the major product of each of the following reactions? Assume that there is an equivalent amount of each reagent.

Draw resonance contributors for the following ions:

Draw all the products of the following reaction:

Are the following pairs of structures resonance contributors or different compounds?

a. How many linear dienes have molecular formula \(C_6 H_{10}\)? (Disregard cis-trans isomers.) b. How many of the linear dienes in part a are conjugated dienes? c. How many are isolated dienes?

a. Draw resonance contributors for the following species. Do not include structures that are so unstable that their contributions to the resonance hybrid would be negligible. Indicate which are major contributors and which are minor contributors to the resonance hybrid. 1. \(\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CHOCH}_{3}\) b. Do any of the species have resonance contributors that all contribute equally to the resonance hybrid? Equation Transcription: Text Transcription: CH_3 CH=CHOCH_3

Which ion in each of the following pairs is more stable and why?

Which compound would you expect to have the greater heat of hydrogenation, 1,2-pentadiene or 1,4-pentadiene?

Which resonance contributor in each pair makes the greater contribution to the resonance hybrid?

Classify the following species as aromatic, nonaromatic, or antiaromatic:

a. Which oxygen atom has the greater electron density? b. Which compound has the greater electron density on its nitrogen atom? c. Which compound has the greater electron density on its oxygen atom?

Which compound is the strongest base?

Which can lose a proton more readily, a methyl group bonded to cyclohexane or a methyl group bonded to benzene?

Problem 72P The triphenylmethyl cation is so stable that a salt such as triphenylmethyl chloride can be isolated and stored. Why is this carbocation so stable?

1. The B ring ( Section \(3.15\) ) of cortisone, a steroid, is formed by a Diels–Alder reaction using the two reactants shown here. What is the product of this reaction? 2. The C ring of estrone (a steroid) is formed by a Diels–Alder reaction using the two reactants shown here. What is the product of this reaction? Equation Transcription: Text Transcription: 3.15

Answer the following questions and explain the reason for each answer: a. Which compound is a stronger acid? b. Which compound is a stronger base?

Draw the resonance contributors for the following anion and rank them in order from most stable to least stable.

Rank the following compounds in order from most stable to least stable:

Which species in each pair is more stable?

Which species in each of the pairs in \(\text{Problem} \ 77\) is the stronger base? Equation Transcription: Problem 77 Text Transcription: Problem 77

Purine is a heterocyclic compound with four nitrogen atoms. a. Which nitrogen is most apt to be protonated? b. Which nitrogen is least apt to be protonated?

Which of the following compounds is the strongest acid?

Why is the delocalization energy of pyrrole \((21 \ \mathrm{kcal} / \mathrm{mo}l)\) greater than that of furan \((16 \ \mathrm{kcal} / \mathrm{mo}l)\)? Equation Transcription: 21 kcal/mol 16 kcal/mol Text Transcription: 21 kcal/mol 16 kcal/mol

Rank the indicated hydrogen in the following compounds in order from most acidic to least acidic:

Problem 83P Answer the following questions for the ? molecular orbitals (MOs) of 1,3,5,7-octatetraene: a. How many MOs does the compound have? b. Which are the bonding MOs and which are the antibonding MOs? c. Which MOs are symmetric and which are antisymmetric? d. Which MO is the HOMO and which is the LUMO in the ground state? e. Which MO is the HOMO and which is the LUMO in the excited state? f. What is the relationship between HOMO and LUMO and symmetric and antisymmetric orbitals? g. How many nodes does the highest-energy MO of 1,3,5,7-octatetraene have between the nuclei?

How could you synthesize the following compound from starting materials containing no more than six carbons? ( Hint: A \(1,6-\text{diketone}\) can be synthesized by oxidative cleavage of a \(1,2-\text{disubstituted cyclohexene}\).) Equation Transcription: 1,6-diketone 1,2-disubstituted cyclohexene Text Transcription: 1,6-diketone 1,2-disubstituted cyclohexene

A student obtained two products from the reaction of 1,3-cyclohexadiene with \(Br_2\) (disregarding stereoisomers). His lab partner was surprised when he obtained only one product from the reaction of 1,3-cyclohexadiene with HBr (disregarding stereoisomers). Account for these results.

How could the following compounds be synthesized using a Diels–Alder reaction?

1. How could each of the following compounds be prepared from a hydrocarbon in a single step? 2. What other organic compound would be obtained from each synthesis?

Problem 88P Draw the products obtained from the reaction of 1 equiv HBr with 1 equiv 1,3,5-hexatriene. a. Which product(s) will predominate if the reaction is under kinetic control? b. Which product(s) will predominate if the reaction is under thermodynamic control?

Problem 89P How would the following substituents affect the rate of a Diels–Alder reaction? a. an electron-donating substituent in the diene b. an electron-donating substituent in the dienophile c. an electron-withdrawing substituent in the diene

Problem 90P Give the major products obtained from the reaction of one equivalent of HCI with the following: a. 2,3-dimethyl-1,3-pentadiene ________________ b. 2,4-dimethyl-1,3-pentadiene

The acid dissociation constant \((\mathrm{K}_\mathrm{a})\) for loss of a proton from cyclohexanol is \(1 \times 10^{-16}\) a. Draw an energy diagram for loss of a proton from cyclohexanol. b. Draw the resonance contributors for phenol. c. Draw the resonance contributors for the phenolate ion. d. On the same plot with the energy diagram for loss of a proton from cyclohexanol, draw an energy diagram for loss of a proton from phenol. e. Which has a greater \((\mathrm{K}_\mathrm{a})\), cyclohexanol or phenol? f. Which is a stronger acid, cyclohexanol or phenol? Equation Transcription: Ka 1 10-16 Text Transcription: K_a 1 times 10^-16

Protonated cyclohexylamine has a \(\mathrm{K}_\mathrm{a} = 1 \times 10^{-11}\). Using the same sequence of steps as in \(\text{Problem} \ 91\) , determine which is a stronger base, cyclohexylamine or aniline. Equation Transcription: Ka = 1 10-11 Problem 91 Text Transcription: K_a = 1 times 10^-11 Problem 91

Draw the product or products that would be obtained from each of the following reactions:

What two sets of a conjugated diene and a dienophile could be used to prepare the following compound?

1. Which dienophile in each pair is more reactive in a Diels–Alder reaction? 2. Which diene is more reactive in a Diels–Alder reaction?

Problem 96P Cyclopentadiene can react with itself in a Diels–Alder reaction. Draw the endo and exo products.

Which diene and which dienophile could be used to prepare each of the following?

1. Propose a mechanism for the following reaction: 2. What is the product of the following reaction?

Problem 100P As many as 18 different Diels–Alder products can be obtained by heating a mixture of 1,3-butadiene and 2-methyl-1,3-butadiene. Identify the products.

1. What are the products of the following reaction? 2. How many stereoisomers of each product could be obtained?

Problem 101P On a single graph, draw the reaction coordinate diagram for the addition of one equivalent of HBr to 2 methyl-1,3-pentadiene and for the addition of one equivalent of HBr to 2-methyl-1,4-pentadiene. Which reaction is faster?

While attempting to recrystallize maleic anhydride, a student dissolved it in freshly distilled cyclopentadiene rather than in freshly distilled cyclopentane. Was his recrystallization successful?

The following equilibrium is driven to the right if the reaction is carried out in the presence of maleic anhydride (see \(\text{Problem} \ 102\)). What is the function of maleic anhydride? Equation Transcription: Problem 102 Text Transcription: Problem 102

In 1935, J. Bredt, a German chemist, proposed that a bicycloalkene could not have a double bond at a bridgehead carbon unless one of the rings contains at least eight carbons. This is known as Bredt’s rule. Explain why there cannot be a double bond at this position.

The experiment shown next and discussed in \(\text{Section} \ 8.18\) shows that the proximity of the chloride ion to \(\mathrm{C}-2\) in the transition state causes the \(1,2-\text{addition product}\) to be formed faster than the \(1,4-\text{addition product}\). a. Why was it important for the investigators to know that the preceding reaction was being carried out under kinetic control? b. How could the investigators know that the reaction was being carried out under kinetic control? Equation Transcription: Section 8.18 C-2 1,2-addition product 1,4-addition product Text Transcription: Section 8.18 C-2 1,2-addition product 1,4-addition product

The product of the following reaction has a fused bicyclic ring. What is its structure?

Problem 107P Draw the resonance contributors of the cyclooctatrienyl dianion. a. Which of the resonance contributors is the least stable? b. Which of the resonance contributors makes the smallest contribution to the hybrid?

Investigation has shown that cyclobutadiene is actually a rectangular molecule rather than a square molecule, and that there are two different \(1,2-\text{dideuterio}-\) \(1,3-\text{cyclobutadienes}\). Explain the reason for these unexpected observations. Equation Transcription: 1,2-dideuterio- 1,3-cyclobutadienes Text Transcription: 1,2-dideuterio- 1,3-cyclobutadienes