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

Question 1

What do the Suzuki reaction, the Heck reaction, and the organocuprate reaction all have in common when they react with an alkyl halide?

A) All reactions form new carbon-carbon bonds.
B) They all use palladium as a catalyst in one step of the reaction.
C) They are all stereospecific reactions.
D) They all require harsh conditions.

Answer 1

All reactions form new carbon-carbon bonds.

Question 2

Which of the following statements is not true about a carbene?

A) A carbene is a neutral reactive intermediate.
B) A carbene contains a divalent carbon.
C) A carbene is sp³ hybridized.
D) A carbene is surrounded by six electrons.

Answer 2

A carbene is sp³ hybridized.

Question 3

Which of the following descriptions does not apply to methylene?

A) Methylene is sp² hybridized.
B) Methylene is a neutral, reactive intermediate.
C) Methylene is a radical intermediate.
D) The formula of methylene is :CH₂.

Answer 3

Methylene is a radical intermediate.

Question 4

What is the missing reactant in the following reaction?

A) I
B) II
C) III
D) IV

Question 5

What products are formed when diazomethane is heated?

A) methane gas and nitrogen gas
B) propene gas and nitrogen gas
C) methyl radical and nitrogen gas
D) methylene and nitrogen gas

Question 6

Organocuprate reagents (R₂CuLi) react with several compounds. Which listed reaction is not correct?

A) Acid chlorides react with organocuprate reagents to form ketones.
B) Epoxides react with organocuprate reagents to form alcohols.
C) Alkyl halides react with organocuprate reagents to form coupling products containing a new carbon-carbon bond.
D) Carbon dioxide reacts with organocuprate reagents to form carboxylic acids.

Question 7

Identify the products of the following reaction.

A) A
B) B
C) C
D) D

Question 8

What is the major organic product of the following reaction?

A) I
B) II
C) III
D) IV

Question 9

What is the major organic product of the following reaction?

A) I
B) II
C) III
D) IV

Question 10

Which statement below best explains what is meant by the statement, "An organocuprate reaction with a vinyl halide is stereospecific"?

A) The reaction of a specific stereoisomer with the R₂CuLi reagent will yield that particular stereoisomer as the product.
B) The reaction of a vinyl halide with the R₂CuLi reagent will only yield the cis product.
C) The reaction of a vinyl halide with the R₂CuLi reagent will only yield the trans product.
D) The reaction of a vinyl halide with the R₂CuLi reagent will only yield one enantiomer product-either R or S configuration.

Question 11

Which of the reactions listed below is not stereospecific?

A) Suzuki reaction
B) organocuprate coupling reaction
C) Heck reaction
D) Simmons-Smith reaction

Question 12

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

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.

Question 13

Identify the products of the following reaction.

A) I
B) II
C) III
D) IV

Question 14

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

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 bond

Question 15

What is the major organic product of the following reaction?

A) I
B) II
C) III
D) IV

Question 16

Which of the following is true about the use of the Grubbs catalyst?

A) The Grubbs catalyst is used in carbon-carbon coupling reactions.
B) The Grubbs catalyst is used in alkene metathesis.
C) The Grubbs catalyst is used in carbene formation.
D) The Grubbs catalyst is used with palladium as a co-catalyst.

Question 17

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

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.

Question 18

Which class of compounds listed below does not react with organocuprate reagents to form a coupling product that contains a new carbon-carbon bond?

A) 1° alkyl halides
B) 3° alkyl halides
C) vinyl halides
D) aryl halides

Question 19

Choose the statement below that is not true about the Suzuki reaction.

A) The product of the Suzuki reaction is completely stereospecific.
B) The Suzuki reaction involves both an organoborane reagent and an organopalladium catalyst.
C) The Suzuki reaction forms more highly substituted alkenes.
D) The Suzuki reaction involves an oxidative addition followed by a reductive elimination.

Question 20

Coupling reactions with vinyl halides are stereospecific. Which choice below best describes the expected product when trans-1-bromo-1-hexene reacts with (CH₃)₂CuLi?

A) The reaction will only yield a trans-alkene.
B) The reaction will only yield a cis-alkene.
C) The reaction will only yield one enantiomeric product with R configuration.
D) The reaction will only yield one enantiomeric product with S configuration.

Question 21

Identify the major organic product of the following reaction.

A) I
B) II
C) III
D) IV

Question 22

Identify the major organic product of the following reaction.

A) I
B) II
C) III
D) IV

Question 23

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

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.

Question 24

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?

A) I
B) II
C) III
D) IV

Question 25

What is the major organic product of the following reaction?

A) I
B) II
C) III
D) IV

Question 26

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

A) I
B) II
C) III
D) IV

Question 27

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

A) I
B) II
C) III
D) IV

Question 28

What is the major organic product of the following reaction?

A) I
B) II
C) III
D) None of the choices is correct

Question 29

Identify the major organic product of the following reaction.

A) I
B) II
C) III
D) IV

Question 30

Identify the structure of the major organic product that results from the following reaction.

A) I
B) II
C) III
D) IV

Question 31

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

A) a carbocation
B) a carbanion
C) a free radical
D) a carbene

Question 32

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

A) I
B) II
C) III
D) IV

Question 33

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

A) I
B) II
C) III
D) IV

Question 34

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

A) (1) HBr, H₂O₂; (2) KOC(CH₃)₃ ; (3) MCPBA; (4) CH₂=CPh₂
B) (1) NBS, hv ; (2) KOC(CH₃)₃ ; (3) CHBr₃, KO(CH₃)₃ ; (4) a. LiCuPh₂, b. H₂O
C) (1) H₂SO₄(aq.), $\Delta$ ; (2) MCPBA; (3) CHBr₃, KO(CH₃)₃ ; (4) CH₂=CPh₂
D) (1) Br₂, FeBr₃ ; (2) MCPBA; (3) CHBr₃, KO(CH₃)₃ ; (4) Ph₂COCl

Question 35

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

A) I
B) II
C) III
D) IV

Question 36

Why is the Grubbs catalyst synthetically important?

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.

Question 37

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

A) Lewis base.
B) electrophile.
C) nucleophile.
D) Brønsted-Lowry base.

Question 38

As shown below, when cis-2-butene reacts with dichlorocarbene, only the cis-1,1-dichloro-2,3-dimethylcyclopropane is formed. What can we conclude about the nature of the reaction mechanism?

A) The mechanism is an S_N1 mechanism.
B) The mechanism is a concerted.
C) The mechanism proceeds through a radical intermediate.
D) The mechanism is an E2 mechanism.

Question 39

What would be the starting material for the following product that was made via a Grubbs catalyst?

A) I
B) II
C) III
D) IV

Question 40

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

A) I
B) II
C) III
D) IV

Question 41

What is the appropriate sequence of starting material and reagents that will produce the target molecule shown below?

A) I
B) II
C) III
D) IV