Question 1

Many of the reactions studied in this chapter are stereospecific. Why are stereospecific reactions important?

Accepted Answer

A)   When a reaction produces a mixture of enantiomers, it is often very difficult to separate them. A mixture of products is often not useful.
B)   Often stereoisomers of a particular compound will have very different biological effects on an organism. Only one isomer is biologically helpful, and the other may be harmful.
C)   Often only one stereoisomer is biologically active, and coupling reactions are often used for the production of biological materials.
D)   All of the choices are true.E) A) and B)
F) All of the above

Question 2

Identify the products of the following reaction.

Accepted Answer

A)   A
B)   B
C)   C
D)   DE) A) and B)
F) C) and D)

Question 3

What is the name for the type of intermediate X formed in the reaction sequence below?

Accepted Answer

A)   a carbocation
B)   a carbanion
C)   a free radical
D)   a carbeneE) All of the above
F) None of the above

Question 4

What is the missing reactant in the following reaction?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and B)
F) A) and C)

Question 5

Identify the starting material that would be used to form the following product in a ring-closing metathesis reaction utilizing a Grubbs catalyst?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and B)
F) A) and C)

Question 6

What is the appropriate sequence of reagents that will produce the target molecule shown below from ethylbenzene? 2O2; (2)  KOC(CH3) 3 ; (3)  MCPBA; (4)  CH2=CPh2 B)  (1)  NBS, h ; (2)  KOC(CH3) 3 ; (3)  CHBr3, KO(CH3) 3 ; (4)  a. LiCuPh2, b. H2O C)  (1)  H2SO4(aq.) ,  ; (2)  MCPBA; (3)  CHBr3, KO(CH3) 3 ; (4)  CH2=CPh2 D)  (1)  Br2, FeBr3 ; (2)  MCPBA; (3)  CHBr3, KO(CH3) 3 ; (4)  Ph2COCl" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   (1)  HBr, H2O2; (2)  KOC(CH3) 3 ; (3)  MCPBA; (4)  CH2=CPh2
B)   (1)  NBS, h ; (2)  KOC(CH3) 3 ; (3)  CHBr3, KO(CH3) 3 ; (4)  a. LiCuPh2, b. H2O
C)   (1)  H2SO4(aq.) ,  ; (2)  MCPBA; (3)  CHBr3, KO(CH3) 3 ; (4)  CH2=CPh2
D)   (1)  Br2, FeBr3 ; (2)  MCPBA; (3)  CHBr3, KO(CH3) 3 ; (4)  Ph2COClE) A) and C)
F) A) and B)

Question 7

What would be the major organic product of the following Heck reaction?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and D)
F) A) and C)

Question 8

Which of the following statements is not true about the Simmons-Smith reaction?

Accepted Answer

A)   The Simmons-Smith reaction involves the formation of a free carbene.
B)   The Simmons-Smith reaction uses the reagents zinc-copper couple.
C)   The Simmons-Smith reaction is stereospecific.
D)   The Simmons-Smith reaction involves CH2I2 reacting with a copper-activated zinc reagent.E) B) and D)
F) A) and B) A

Question 9

Identify the products of the following reaction.

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and D)
F) B) and C)

Question 10

Identify the structure of the organic product Y formed in the following reaction sequence.

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) All of the above
F) A) and B)

Question 11

What is the major organic product of the following reaction?

Accepted Answer

A)   I
B)   II
C)   III
D)   None of the choices is correctE) All of the above
F) A) and B)

Question 12

Identify the major organic product of the following reaction.

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and B)
F) B) and C)

Question 13

Which of the following is not a step in the Suzuki reaction?

Accepted Answer

A)   Oxidative addition of R-X to the palladium catalyst
B)   Substitution of the R group to the palladium catalyst
C)   Transfer of the alkyl group from the organoborane to palladium
D)   Reductive elimination of R-R, forming the new C-C bondE) All of the above
F) A) and C)

Question 14

What is the major organic product of the following reaction?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) C) and D)
F) B) and D) A

Question 15

Dichlorocarbene reacts with an alkene to form a cyclopropane derivative. In this reaction the dichlorocarbene acts as a(n)

Accepted Answer

A)   Lewis base.
B)   electrophile.
C)   nucleophile.
D)   Brønsted-Lowry base.E) All of the above
F) None of the above

Question 16

Which of the reactions listed below is not stereospecific?

Accepted Answer

A)   Suzuki reaction
B)   organocuprate coupling reaction
C)   Heck reaction
D)   Simmons-Smith reactionE) C) and D)
F) All of the above

Question 17

Why is the Grubbs catalyst synthetically important?

Accepted Answer

A)   Because it only requires dilute concentrations of the reactants.
B)   Because it produces only stereospecific products.
C)   Because it produces only stereoselective products.
D)   Because it provides a synthetic pathway for ring-closing metathesis reactions.E) B) and D)
F) B) and C)

Question 18

Compound X can be synthesized via a ring-closing metathesis reaction when treated with a Grubbs' catalyst. What is a possible structure of the starting material for this reaction?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and B)
F) B) and C) A

Question 19

What starting material could yield the following compound if Simmons-Smith conditions were used?

Accepted Answer

A)   I
B)   II
C)   III
D)   IVE) A) and D)
F) A) and C)

Question 20

Which of the following correctly describes a reaction yielding a dichorocarbene?

Accepted Answer

A)   The reaction of chloroform with KOC(CH3) 3.
B)   The reaction of chloroform with Zn(Cu) .
C)   The reaction of chloroform with (CH3) 2CuLi.
D)   The reaction of diazomethane with KOC(CH3) 3.E) None of the above
F) A) and D)

Exam 26: Carbon-Carbon Bond Forming Reactions in Organic Synthesis

Many of the reactions studied in this chapter are stereospecific. Why are stereospecific reactions important?

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Identify the products of the following reaction.

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What is the name for the type of intermediate X formed in the reaction sequence below?

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What is the missing reactant in the following reaction?

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Identify the starting material that would be used to form the following product in a ring-closing metathesis reaction utilizing a Grubbs catalyst?

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What is the appropriate sequence of reagents that will produce the target molecule shown below from ethylbenzene?

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What would be the major organic product of the following Heck reaction?

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Which of the following statements is not true about the Simmons-Smith reaction?

Correct AnswerverifiedA

Identify the products of the following reaction.

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Identify the structure of the organic product Y formed in the following reaction sequence.

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What is the major organic product of the following reaction?

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Identify the major organic product of the following reaction.

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Which of the following is not a step in the Suzuki reaction?

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What is the major organic product of the following reaction?

Correct AnswerverifiedA

Dichlorocarbene reacts with an alkene to form a cyclopropane derivative. In this reaction the dichlorocarbene acts as a(n)

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Which of the reactions listed below is not stereospecific?

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Why is the Grubbs catalyst synthetically important?

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Compound X can be synthesized via a ring-closing metathesis reaction when treated with a Grubbs' catalyst. What is a possible structure of the starting material for this reaction?

Correct AnswerverifiedA

What starting material could yield the following compound if Simmons-Smith conditions were used?

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Which of the following correctly describes a reaction yielding a dichorocarbene?

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