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Bruice 8th EditionCh. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions문제 35
What characteristics must the reactant of a stereospecific reaction have?
문제 36a,b,c
a. Is the reaction of 2-butene with HBr regioselective?
b. Is it stereoselective?
c. Is it stereospecific?
문제 36d,e,f
d. Is the reaction of 1-butene with HBr regioselective?
e. Is it stereoselective?
f. Is it stereospecific?
문제 37b
What stereoisomers are obtained from each of the following reactions?
b.
문제 40
a. What stereoisomers are formed in the following reaction? Are they enantiomers or diastereomers?
b. Which stereoisomer is formed in greater yield?
문제 41(1)
a. What alkene is required to synthesize each of the following compounds?
b. What other epoxide is formed in each synthesis?
c. Assign an R or S configuration to each asymmetric center.
1.
문제 41(2)
a. What alkene is required to synthesize each of the following compounds?
b. What other epoxide is formed in each synthesis?
c. Assign an R or S configuration to each asymmetric center.
2.
문제 42a,b
What stereoisomers are obtained from hydroboration–oxidation of the following compounds? Assign an R or S configuration to each asymmetric center.
a. cyclohexene
b. 1-ethylcyclohexene
문제 42c
What stereoisomers are obtained from hydroboration–oxidation of the following compounds? Assign an R or S configuration to each asymmetric center.
c. cis-2-butene
문제 42d
What stereoisomers are obtained from hydroboration–oxidation of the following compounds? Assign an R or S configuration to each asymmetric center.
d. (Z)-3,4-dimethyl-3-hexene
문제 43
The reaction of 2-ethyl-1-pentene with Br2, with H2 + Pd/C, or with R2BH/THF followed by aqueous HO- + H2O2 leads to a racemic mixture. Explain why a racemic mixture is obtained in each case.
문제 44
Using a sample of trans-2-pentene, how could you prove that the addition of Br2 forms a cyclic bromonium ion intermediate rather than a carbocation intermediate?
문제 45c,d
What stereoisomers are obtained from the following reactions?
c. (E)-3-methyl-2-pentene + HBr
d. cis-3-hexene + HBr
문제 46
When Br2 adds to a cis alkene that has different substituents attached to each of the two sp2 carbons, such as cis-2-heptene, identical amounts of the two threo enantiomers are obtained even though Br- is more likely to add to the less sterically hindered carbon of the bromonium ion. Explain why identical amounts of the two enantiomers are obtained.
문제 49c,d
What stereoisomers would you expect to obtain from each of the following reactions?
c.
d.
문제 50
a. What is the major product obtained from the reaction of propene and Br2 plus excess Cl-?
b. Indicate the relative amounts of the stereoisomers that are obtained.
문제 51b
What is the product of the reaction of maleate and H2O when H2SO4 is used as a catalyst instead of fumarase?
문제 53a
Show how each of the following compounds can be synthesized from an alkene:
a.
문제 53b
Show how each of the following compounds can be synthesized from an alkene:
b.
문제 53c
Show how each of the following compounds can be synthesized from an alkene:
c.
문제 54
Explain why 3-methylcyclohexene should not be used as the starting material in Problem 52b.
문제 56a
Which electrophilic addition reactions
a. form a carbocation intermediate? intermediate?
문제 56c
Which electrophilic addition reactions
c. form a three-membered ring
문제 56d
Which electrophilic addition reactions
d. form a five-membered ring intermediate?
문제 57a
Identify the electrophile and the nucleophile in each of the following reaction steps and then draw curved arrows to illustrate the bond-making and bondbreaking processes.
a.
문제 57b
Identify the electrophile and the nucleophile in each of the following reaction steps and then draw curved arrows to illustrate the bond-making and bondbreaking processes.
b.
문제 57c
Identify the electrophile and the nucleophile in each of the following reaction steps and then draw curved arrows to illustrate the bond-making and bondbreaking processes.
c.
문제 58a
What is the major product of the reaction of 2-methyl-2-butene with each of the following reagents?
a. HBr
문제 58b
What is the major product of the reaction of 2-methyl-2-butene with each of the following reagents?
b. HI
문제 58d
What is the major product of the reaction of 2-methyl-2-butene with each of the following reagents?
d. O3, −78 °C, followed by (CH3)2S
