8Wade - Practice Problems PDF

Preview

Summary

Practice Problems...

Description

Organic Chemistry, 8e (Wade) Chapter 8 Reactions of Alkenes 1) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 1 Section: 8.3 2) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 1 Section: 8.3 3) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 1 Section: 8.3

4) HBr can be added to an alkene in the presence of peroxides (ROOR). What function does the peroxide serve in this reaction? A) nucleophile B) electrophile C) radical chain initiator D) acid catalyst E) solvent Answer: C Diff: 2 Section: 8.3 5) Predict the major product of the following reaction.

A) B) C) D) Answer: B Diff: 2 Section: 8.3 6) Name the major product which results when HBr is added to 3-ethyl-3-hexene. Answer: 3-bromo-3-ethylhexane Diff: 2 Section: 8.3

7) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.3 8) Provide the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.3 9) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.3

10) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer: Diff: 2 Section: 8.3 11) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.3 12) Based on the relative stabilities of the intermediates involved, explain the basis for Markovinkov's rule in the addition of hydrogen halides to alkenes. Answer: The rate-determining step in this reaction is the production of a carbocation intermediate. Since this step is endothermic, Hammond's postulate allows one to gauge the relative stabilities of the transition states by comparing the relative stabilities of the carbocation intermediates. The reaction pathway which produces the more substituted carbocation will thus occur more rapidly. Diff: 2 Section: 8.3 13) Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

Answer:

Diff: 2

Section: 8.3

14) When propylene reacts with hydrogen bromide in the presence of a peroxide initiator, which of the following structures are formed during the mechanism? A) B) C) D) H∙ Answer: B Diff: 2 Section: 8.3 15) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 3 Section: 8.3 16) Draw the major regioisomeric product generated in the reaction below.

Answer:

Diff: 3

Section: 8.3

17) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.3 18) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.3 19) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.3 20) Explain the regioselectivity observed in the radical addition of HBr to 2-methylpropene. Answer: The reaction proceeds via the addition of Br∙ to the alkene. Two competing pathways are possible, but the transition state leading to the more substituted alkyl radical is lower in energy. This process ultimately makes the addition anti-Markovnikov in nature. Diff: 3

Section: 8.3

21) When 3,6-dimethylcyclohexene is reacted with dry gaseous HBr, one of the products is 1-bromo-1,4-dimethylcyclohexane. Provide a detailed step-by-step mechanism to explain the formation of this product Answer:

Diff: 3 Section: 8.3 22) The following reaction is known to proceed by a free radical chain mechanism. Suggest a reasonable, step-by-step mechanism for this reaction. CH3CHCH2 + CHCl3 Answer: ROOR → 2 RO∙

CH3CH2CH2CCl3

RO∙ + HCCl3 → ROH + ∙CCl3

Cl3C∙ + CH2CHCH3 → Cl3CCH2

Cl3CCH2 Diff: 3 Section: 8.3

CH3

CH3 + HCCl3 → Cl3CCH2CH2CH3 + ∙CCl3

23) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 1

Section: 8.4

24) The mechanism for the acid-catalyzed hydration of alkenes is simply the reverse of the mechanism by which alcohols are dehydrated using concentrated acid. This is an illustration of the principle of ________. Answer: microscopic reversibility Diff: 1 Section: 8.4 25) Acid catalyzed hydration (H2SO4/water/△) of an unknown compound (A)with a chemical formula C6H12, yielded a racemic mixture of product C6H13OH. Which, if any, of the following compounds is/are possible structures for the initial compound (A)?

A) compound 1 only B) compounds 2 and 3 C) compound 2 only D) compounds 1 and 3 E) none of the above Answer: E Diff: 2 Section: 8.4 26) Name the major alcohol product which results when 3,3-dimethylbut-1-ene is treated with dilute acid. Answer: 2,3-dimethyl-2-butanol Diff: 2 Section: 8.4 27) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.4

28) What is the major product of the following reaction?

A)

B) C)

D)

Answer: D Diff: 2 Section: 8.4 29) Draw the major organic product(s) generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.4

30) Which of the following intermediates is thought to occur in the mechanism by which alkenes are hydrated in the presence of acid? A) carbanion B) carbocation C) free radical D) carbene E) alkyne Answer: B Diff: 2 Section: 8.4 31) Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

Answer:

Diff: 2 Section: 8.4 32) Provide the reagents necessary to complete the following transformation.

A) 1. BH3∙THF 2. H2O2, HOB) H2O, H2SO4 C) OsO4, H2O2 D) CH3CO3H E) 1. CH3CO3H 2. H+, H2O Answer: B Diff: 2 Section: 8.4

33) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 3 Section: 8.4 34) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.4

35) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.4 36) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer: Diff: 3 Section: 8.4 37) Provide the reagents necessary to complete the following transformation.

Answer: 1. Br2, hν 2. H2O, Δ or 1. Br2, hν 2. NaOCH3, CH3OH 3. H3O+ or Hg(OAc)2, H2O; NaBH4 Diff: 3 Section: 8.4

38) Which of the following is the best reaction sequence to use if one wants to accomplish a Markovnikov addition of water to an alkene with minimal skeletal rearrangement? A) water + dilute acid B) water + concentrated acid C) oxymercuration-demercuration D) hydroboration-oxidation E) none of the above Answer: C Diff: 1 Section: 8.5 39) What synthetic goal is achieved by subjecting an alkene to an oxymercurationdemercuration sequence? A) Markovnikov addition of H2O wherein skeletal rearrangement is promoted B) Markovnikov addition of H2O wherein skeletal rearrangement is prevented C) anti-Markovnikov addition of H2O wherein skeletal rearrangement is promoted D) anti-Markovnikov addition of H2O wherein skeletal rearrangement is prevented E) syn-hydroxylation Answer: B Diff: 2 Section: 8.5 40) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.5 41) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.5 42) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.5 43) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.5 44) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.5

45) When an alkene is subjected to treatment with Hg(OAc) 2 in alcohol followed by reaction with NaBH4, what new class of compound is formed? A) ether B) epoxide C) alkane D) syn diol E) alkyne Answer: A Diff: 2 Section: 8.6 46) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.6 47) Provide the reagents necessary to convert 3-methyl-2-butanol to 2-methyl-2-butanol. Answer: 1. conc. H2SO4 2. H3O+ or Hg(OAc)2, H2O followed by NaBH4 or 1. PBr3 2. NaOCH3, CH3OH 2. H3O+ or Hg(OAc)2, H2O followed by NaBH4 Diff: 2 Section: 8.6

48) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer: Diff: 3 Section: 8.6 49) Treatment of 2-methylpropene with which of the following reaction conditions results in an anti-Markovnikov addition product? A) dry gaseous HBr with peroxides present B) BH3-THF, followed by alkaline H2O2 C) aqueous Hg(OAc)2, followed by alkaline NaBH4 D) dilute H2SO4 and heat E) both A and B Answer: E Diff: 1 Section: 8.7 50) Both (E)- and (Z)-hex-3-ene can be subjected to a hydroboration-oxidation sequence. How are the products from these two reactions related to each other? A) The (E)- and (Z)-isomers generate the same products but in differing amounts. B) The (E)- and (Z)-isomers generate the same products in exactly the same amounts. C) The products of the two isomers are related as constitutional isomers. D) The products of the two isomers are related as diastereomers. E) The products of the two isomers are not structurally related. Answer: B Diff: 2 Section: 8.7 51) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.7 52) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.7 53) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.7 54) Complete the following reaction by filling in the appropriate reagents.

Answer:

Diff: 2 Section: 8.7

55) Provide the reagents necessary to complete the following transformation.

A) 1. BH3∙THF 2. H2O2, HOB) H2O, H2SO4 C) OsO4, H2O2 D) CH3CO3H E) 1. CH3CO3H 2. H+, H2O Answer: A Diff: 2 Section: 8.7 56) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 3 Section: 8.7 57) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.7 58) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.7 59) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

(Z)-3-hexene Answer:

→

Diff: 3 Section: 8.7 60) Draw a structure for the transition state of the following reaction. Include correct partial charges.

Answer:

Diff: 3

Section: 8.7

61) Which of the following additions to alkenes occur(s) specifically in an anti fashion? A) hydroboration-oxidation B) addition of Br2 C) addition of H2 D) addition of H2O in dilute acid E) both A and B Answer: B Diff: 1 Section: 8.8 62) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 1 Section: 8.8 63) Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

Answer:

Diff: 1 Section: 8.8 64) Addition of Br2 to (E)-hex-3-ene produces ________. A) a meso dibromide B) a mixture of enantiomeric dibromides which is optically active C) a mixture of enantiomeric dibromides which is optically inactive D) (Z)-3,4-dibromo-3-hexene E) (E)-3,4-dibromo-3-hexene Answer: A

Diff: 2 Section: 8.8

65) Which of the following alkenes will yield a meso dihalide when reacted with Br2/CCl4 at room temperature? A)

B)

C)

D)

E) both Band D Answer: B Diff: 2 Section: 8.8 66) Provide the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.8

67) Draw the major organic product(s) generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.8 68) Provide a detailed, step-by-step mechanism for the reaction shown below.

Answer:

Diff: 2 Section: 8.8 69) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.8

70) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.8 71) Consider how the ICl bond is polarized and predict the product which results when this mixed halogen adds to 1-methylcyclohexene. Answer:

Diff: 3 Section: 8.8 72) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.9

73) Predict the product of the following reaction. Include any relevant stereochemistry.

Answer:

Diff: 3 Section: 8.9 74) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.9 75) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.9

76) Complete the following reaction by providing a structure of the expected product. Be sure to indicate all relevant stereochemistry.

Answer:

Diff: 3 Section: 8.9 77) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer: Diff: 1 Section: 8.10 78) Both (E)- and (Z)-hex-3-ene can be treated with D2 in the presence of a platinum catalyst. How are the products from these two reactions related to each other? A) The (E)- and (Z)-isomers generate the same products but in differing amounts. B) The (E)- and (Z)-isomers generate the same products in exactly the same amounts. C) The products of the two isomers are related as constitutional isomers. D) The products of the two isomers are related as diastereomers. E) The products of the two isomers are related as enantiomers. Answer: D Diff: 2 Section: 8.10 79) ________ is the use of an optically active reagent or catalyst to convert an optically inactive starting material into an optically active product. A) Asymmetric induction B) Racemization C) Optical reduction

D) Meso effection E) Chiralization Answer: A Diff: 2 Section: 8.10 80) Humulene is a monocyclic terpene constituent of carnations. When 0.25 mol of humulene is hydrogenated in the presence of platinum catalyst, 0.75 mol of H2 reacts with the humulene to produce a monocyclic hydrocarbon of formula C 15H30. What is the molecular formula of humulene? Answer: C15H24 Diff: 2 Section: 8.10 81) Draw the major organic product(s) generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.10 82) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.11

83) Draw the Lewis structure of dibromocarbene. Answer: Diff: 3 Section: 8.11

84) Complete the following reaction by filling in the necessary reagents.

Answer:

Diff: 3 Section: 8.11 85) Provide the reagents necessary to complete the following transformation.

Answer: 1. Br2, hν 2. NaOCH3, CH3OH 3. CH2I2, Zn(Cu) Diff: 3 Section: 8.11 86) Name the compound PhCO3H and give its most common use as a reagent. Answer: peroxybenzoic acid; an oxidizing agent which converts alkenes to epoxides Diff: 1 Section: 8.12 87) Provide the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.12

88) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.12 89) Draw the major organic product(s) generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 2 Section: 8.12 90) Provide the reagents necessary to complete the following transformation.

A) 1. BH3∙THF 2. H2O2, HOB) H2O, H2SO4 C) OsO4, H2O2 D) CH3CO3H E) 1. CH3CO3H 2. H+, H2O Answer: D Diff: 2

Section: 8.12

91) Treatment of cyclopentene with peroxybenzoic acid ________. A) results in oxidative cleavage of the ring to produce an acyclic compound B) yields a meso epoxide C) yields an equimolar mixture of enantiomeric epoxides D) gives the same product as treatment of cyclopentene with OsO4 E) none of the above Answer: B Diff: 3 Section: 8.12 92) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.12 93) Which of the following steps would successfully complete the following reaction?

A) I only B) II & III C) I & IV D) I, II, & IV Answer: A Diff: 3 Section: 8.12

94) Provide the major organic product of the reaction below.

Answer:

Diff: 2 Section: 8.13 95) Provide the reagents necessary to complete the following transformation.

A) 1. BH3∙THF 2. H2O2, HOB) H2O, H2SO4 C) OsO4, H2O2 D) CH3CO3H E) 1. CH3CO3H 2. H+, H2O Answer: E Diff: 2 Section: 8.13 96) Provide the structure of the major organic product of the reaction below.

Answer:

Diff: 3 Section: 8.13 97) Draw the major organic product generated in the reaction below. Pay particular attention to regio- and stereochemical detail.

Answer:

Diff: 3 Section: 8.13 98) Draw the major organic product generated in the reaction below. Pay particular at...