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Problem 1a
Predict the major products of the following reactions, and propose mechanisms to support your predictions.
a. pent-1-ene + HCl
Problem 1b
Predict the major products of the following reactions, and propose mechanisms to support your predictions.
b. 2-methylpropene + HCl
Problem 2a
When 1 mole of buta-1,3-diene reacts with 1 mole of HBr, both 3-bromobut-1-ene and 1-bromobut-2-ene are formed. Propose a mechanism to account for this mixture of products.
Problem 2b
When 1-chlorocyclohexene reacts with HBr, the major product is 1-bromo-1-chlorocyclohexane. Propose a mechanism for this reaction, and explain why your proposed intermediate is more stable than the other possible intermediate
Problem 3b
Predict the major products of the following reactions, and propose mechanisms to support your predictions.
(b)
HINT: Remember to write out complete structures, including all bonds and charges, when writing a mechanism or determining the course of a reaction.
Problem 4a,b
Show how you would accomplish the following synthetic conversions.
(a) but−1−ene → 1−bromobutane
(b) but−1−ene → 2−bromobutane
Problem 4c
Show how you would accomplish the following synthetic conversions.
(c) 2−methylcyclohexanol → 1−bromo−1−methylcyclohexane
Problem 4d
Show how you would accomplish the following synthetic conversions.
(d) 2−methylbutan-2-ol → 2-bromo-3-methylbutane
Problem 5
Propose a mechanism to show how 3,3-dimethylbut-1-ene reacts with dilute aqueous H2SO4 to give 2,3-dimethylbutan-2-ol and a small amount of 2,3-dimethylbut-2-ene.
HINT: When predicting products for electrophilic additions, first draw the structure of the carbocation (or other intermediate) that results from electrophilic attack.
Problem 6a
Predict the products of the following hydration reactions.
a. 1−methylcyclopentene + dilute acid
Problem 6b,c
Predict the products of the following hydration reactions.
b. 2-phenylpropene + dilute acid
c. 1-phenylcyclohexene + dilute acid
Problem 7
a. Propose a mechanism for the following reaction.
b. Give the structure of the product that results when this intermediate is reduced by sodium borohydride.
- Show how you would accomplish the following conversions. a. cis-hex-3-ene to meso-hexane-3,4-diol
Problem 8
- Show how you would accomplish the following conversions. d. trans-hex-3-ene to (d,l)-hexane-3,4-diol
Problem 8
Problem 8a,b
Predict the major products of the following reactions.
a. 1-methylcyclohexene+ aqueous Hg(OAc)2
b. the product from part (a), treated with NaBH4
Problem 8c,d
Predict the major products of the following reactions.
c. 4−chlorocycloheptene + Hg(OAc)2 in CH3OH
d. the product from part (c), treated with NaBH4
Problem 9a,b
Show how you would accomplish the following synthetic conversions.
a. but-1-ene → 2-methoxybutane
b. 1-iodo-2-methylcyclopentane → 1-methylcyclopentanol
Problem 9c
Show how you would accomplish the following synthetic conversions.
c. 3-methylpent-1-ene → 3-methylpentan-2-ol
Explain why acid-catalyzed hydration would be a poor choice for the reaction in (c).
Problem 10a,b
Predict the major products of the following reactions.
a. propene + BH3⋅THF
b. the product from part (a) + H2O2/OH−
Problem 10c,d
Predict the major products of the following reactions.
(c) 2-methylpent-2-ene + BH3⋅THF
(d) the product from part (c) + H2O2/OH−
Problem 11a
Show how you would accomplish the following synthetic conversions.
a. but-1-ene → butan-1-ol
Problem 11b
Show how you would accomplish the following synthetic conversions.
(b) but-1-ene → butan-2-ol
Problem 11c
Show how you would accomplish the following synthetic conversions.
c. 2-bromo-2,4-dimethylpentane → 2,4-dimethylpentan-3-ol
Problem 12
In the hydroboration of 1-methylcyclopentene shown in Solved Problem 8-3, the reagents are achiral, and the products are chiral. The product is a racemic mixture of trans-2-methylcyclopentanol, but only one enantiomer is shown. Show how the other enantiomer is formed.
Problem 13a
Predict the major products of the following reactions. Include stereochemistry where applicable.
(a) 1−methylcyclohexene + BH3⋅THF then H2O2, OH–
Problem 13b
Predict the major products of the following reactions. Include stereochemistry where applicable.
(b) trans-4,4-dimethylpent-2-ene + BH3⋅THF then H2O2, OH–
Problem 13c
Predict the major products of the following reactions. Include stereochemistry where applicable.
(c)
Problem 14a
When (Z)-3-methylhex-3-ene undergoes hydroboration–oxidation, two isomeric products are formed. Give their structures, and label each asymmetric carbon atom as (R) or (S). What is the relationship between these isomers?
Problem 14b
When (E)-3-methylhex-3-ene undergoes hydroboration–oxidation, two isomeric products are formed. Give their structures, and label each asymmetric carbon atom as (R) or (S). What is the relationship between these isomers? What is the relationship between the products formed from (Z)-3-methylhex-3-ene and those formed from (E)-3-methylhex-3-ene?
Problem 15a
Show how you would accomplish the following transformations.
(a)
