Deck 23: Introduction to Organometallic Compounds

Question 1

Which of the following compounds has the most nucleophilic carbon atom?

A) CH₃Cl
B) CH₃Li
C) (CH₃)₂Zn
D) (CH₃)₂Cu

Answer 1

CH₃Li

Question 2

Explain why the solvent for a Grignard reaction must be free of water.

Answer 2

Water consumes the Grignard reagent.

Question 3

Which of the following solvents is/are good solvents to be used in the preparation of organometallic reagents such as organolithiums and Grignard reagents? Select all that apply.

A) ethanol
B) diethyl ether
C) cyclohexanol
D) tetrahydrofuran
E) dioxane

Answer 3

diethyl ether
tetrahydrofuran
dioxane

Question 4

Identify the product when 2-pentanone reacts with one equivalent of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 5

Identify the product when butanal reacts with one equivalent of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 6

What functional group most typically results when a Grignard Reagent reacts with an acid halide, after aqueous workup?

Question 7

Which of the following functional groups does not afford an alcohol when treated with a Grignard reagent followed by a protic work-up.

A) ketone
B) aldehyde
C) ester
D) epoxide
E) nitrile

Question 8

Which alkyl halide is most reactive with magnesium metal?

A) CH₃CH₂CH₂Br
B) CH₃CH₂CH₂F
C) CH₃CH₂CH₂I
D) CH₃CH₂CH₂Cl

Question 9

Diethyl ether is a good solvent to be used with Grignard reagents. Which of the following explanations for this fact is false?

A) It has a very high boiling so it can be heated to drive the Grignard formation to completion.
B) It can serve as a Lewis base and stabilize the Grignard reagent.
C) It is polar enough to stabilize the Grignard reagent.
D) It is aprotic and thus is not acidic enough to react with the Grignard reagent.

Question 10

Which of the following compounds has the most nucleophilic carbon atom?

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

Question 11

Identify the product when formaldehyde reacts with one equivalent of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 12

Which of the following compounds has the most ionic character in the C-M bond?

A) HC≡CMgBr
B) HC≡CK
C) HC≡CNa
D) HC≡CLi

Question 13

Which alkyl halide is least reactive with magnesium metal?

A) CH₃CH₂CH₂Br
B) CH₃CH₂CH₂F
C) CH₃CH₂CH₂I
D) CH₃CH₂CH₂Cl

Question 14

Identify the product when carbon dioxide reacts with one equivalent of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 15

What functional group typically results when an organocopper compound (lithium organocuprate) reacts with an acid chloride?

Question 16

Which of the following compounds has the least nucleophilic carbon atom?

A) CH₃CH₂MgBr
B) CH₃CH₂MgI
C) (CH₃CH₂)₂Zn
D) (CH₃CH₂)₂Cu

Question 17

Which of the following statements is false regarding the preparation of organolithium compounds?

A) Organolithium compounds can be made from alkyl halides (R-X).
B) Organolithium compounds can be made from aryl halides (Ar-X).
C) Vinyl halides cannot be used to form vinyl lithium reagents.
D) Lithium halides are byproducts of the reaction of lithium metal with alkyl halides.
E) It is necessary to use two equivalents of lithium metal.

Question 18

Which of the following is the most polar bond?

A) C-B
B) C-Pd
C) C-Zn
D) C-Pt

Question 19

Identify the product when ethylene oxide reacts with one equivalent of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 20

Why is ethanol not a viable solvent in the synthesis of Grignard reagents?

Question 21

What is the name of the product of the following reaction sequence?

Question 22

Give the final product.

Question 23

What is the product of the following sequence?

Question 24

Give the final product.

Question 25

Which reactant would afford the product shown as the major isomeric product?

A) I
B) II
C) III
D) IV
E) none of the above

Question 26

Which of the following reagents cannot be used in the synthesis of a Gilman reagent?

A) lithium metal
B) lithium halide
C) alkyl halide
D) aryl halide
E) vinyl halide

Question 27

Identify the starting material.

A) I
B) II
C) III
D) IV
E) The product cannot be formed directly from one of the reactants above.

Question 28

Give the final product.

Question 29

Which of the following electrophiles are commonly used with Gilman reagents to form C-C bonds? Select all that apply.

A)acid chlorides
B)α,β-unsaturated ketones
C)esters
D)alkyl halides
E)amides

Question 30

What is the product of the following sequence?

A)I
B)II
C)III
D)IV
E)none of the them

Question 31

Identify the product when an ester reacts with two equivalents of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 32

Identify the product when a nitrile reacts with two equivalent of a Grignard reagents.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 33

What is the product of the following sequence?

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

Question 34

Starting from bromobenzene and any other reagents with two carbons or fewer, propose a synthesis of the compound shown.

Question 35

What is the product of the following sequence?

Question 36

Which of the following statements is(are) true regarding the preparation of Gilman reagents?

A) Gilman reagents can be made from alkyl halides (R-X).
B) Gilman reagents can be made from aryl halides (Ar-X).
C) Gilman reagents can be made from organolithium reagents.
D) Lithium halides are byproducts of the reaction to make Gilman reagents.
E) all of the above

Question 37

Give the final product.

Question 38

What is the product of the following sequence?

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

Question 39

Which of the following electrophiles are commonly used with Gilman reagents to form C-C bonds?

A) alkyl halides
B) aryl halides
C) vinyl halides
D) acyl halides
E) all the above

Question 40

Identify the product when a nitrile reacts with one equivalent of a Grignard reagent.

A) primary alcohol
B) secondary alcohol
C) tertiary alcohol
D) carboxylic acid
E) ketone

Question 41

What product(s) result in the following reaction? Select all that apply.

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

Question 42

A total synthesis of ingenol utilized the Corey-Posner/Whitesides-House coupling reaction in a key C-C bond forming step (J. Am. Chem. Soc. 2002, 124, 9726). Propose a reagent to perform this transformation.

Question 43

What is the product of the following reaction?

Question 44

Gillman reagents are intolerant to the presence of what functional group?

A) ketone
B) ester
C) amide
D) All of the functional groups above are compatible with Gilman reagents.

Question 45

Starting from vinyl chloride and ________ as the only source of carbon atoms, 1-heptene can be synthesized using a Corey-Posner/Whitesides-House coupling reaction.

A) 1-bromopropane
B) 2-bromopentane
C) 1-bromohexane
D) 1-bromopentane

Question 46

Which of the following Gilman reagents could be used with a vinyl halide to afford the (E,E)-diene shown below? Select all that apply.

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

Question 47

What is the product of the following reaction?

A) (E)-1-phenyl-1-pentene
B) (Z)-1-phenyl-1-pentene
C) (E)-1-phenyl-2-pentene
D) (Z)-1-phenyl-2-pentene
E) 2-phenyl-1-pentene

Question 48

Which of the following statements is false regarding the reactivity of Gilman reagents?

A) They react with acyl halides to give ketones.
B) They react with α,β-unsaturated ketones to give alcohols.
C) They react with alkyl halides or aryl halides in a coupling reaction.
D) They are unreactive with tertiary halides.

Question 49

Which of the following statements is false?

A) Carbenes are generally long lived.
B) Carbenes have a carbon with non-bonding electrons.
C) Carbenes have a carbon missing an octet.
D) Carbenes can be formed by α-elimination.
E) Carbenes are electrophilic.

Question 50

What product(s) result in the following reaction? Select all that apply.

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

Question 51

Which of the following would react fastest in the Corey-Posner/Whitesides-House reaction?

A) cyclohexyl chloride
B) cyclohexyl iodide
C) tert-butyl chloride
D) tert-butyl iodide

Question 52

What are the conditions for the following reaction?

Question 53

Which of the following is a Simmons-Smith cyclopropanation?

A) R-X + Zn →
B) R₂C=CR₂ + CH₂I₂ + Zn-Cu →
C) CHCl₃ + NaOH →
D) R₂C=CHI + (CH₃)₂CuLi →

Question 54

The following synthesis is not likely to work. Which of the following explains why?

A) Lithium cannot react with aryl halides to form organolithium compounds.
B) CH₃CH₂Br does not do cross coupling in Corey-Posner/Whitesides-House reactions.
C) The cuprate formed would react with the ketone.
D) The organolithium formed would react with the ketone.

Question 55

Identify the best reagent for the reaction below.

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

Question 56

Starting from bromobenzene and ________ as the only source of carbon atoms, 1-phenylcyclohexene can be synthesized using a Corey-Posner/Whitesides-House coupling reaction.

A) 1-iodocyclohexene
B) 3-iodocyclohexene
C) iodocyclohexane
D) (iodomethyl)cyclohexane

Question 57

The Corey-Posner/Whitesides-House reaction couples a lithium dialkyl cuprate with all but which of the following?

A) primary alkyl halides
B) tertiary alkyl halides
C) aryl halides
D) methyl halides
E) vinyl halides

Question 58

What product(s) result in the following reaction? Select all that apply.

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

Question 59

What product results in the following reaction?

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

Question 60

The Simmons-Smith reaction involves the formation of _____?

A) alkenes
B) alkynes
C) cyclopropanes
D) cuprates

Question 61

Elaboration of an advanced intermediate toward the synthesis of the pulmoside aglycon is shown below. Give the structures of the intermediates A-C. (J. Am. Chem. Soc. 2013, 135, 2501.)

Question 62

The reaction of a carbene with an alkene to make a cyclopropane commonly goes through which type mechanism?

A) proton transfer
B) loss of leaving group
C) cycloaddition
D) α-elimination

Question 63

What is the product of the following reaction?

A) (2E,4Z)-4-methylhepta-2,4-diene
B) (2Z,4E)-4-methylhepta-2,4-diene
C) (3E,5Z)-4-methylhepta-3,5-diene
D) (3Z,5Z)-4-methylhepta-3,5-diene
E) (3E,5E)-4-methylhepta-3,5-diene

Question 64

The Stille reaction involves coupling of which pair of reagents?

A) organohalide and organotin
B) organohalide and organoboron
C) organotin and organozinc
D) organoboron and organozinc

Question 65

A report on the synthesis of Aromatic Erythrina Alkaloids uses the following transformation (Org. Lett. 2006, 8, 2143). Propose reasonable reaction conditions.

Question 66

Which of the following R groups (R-SnBu₃) would undergo the fastest transmetallation in a Stille coupling reaction?

A) alkyl
B) aryl
C) vinyl
D) benzyl

Question 67

Which of the following R groups (R-SnBu₃) would undergo the slowest transmetallation in a Stille coupling reaction?

A) alkyl
B) aryl
C) vinyl
D) benzyl

Question 68

Which catalysts are common in the Stille coupling reaction?

A) Pd(PPh₃)₄
B) Pd (OAc)₂
C) PdCl₂(PPh₃)₂
D) All of the above

Question 69

The Stille reaction couples organotin reagents with all but one of the following. Which is not a common coupling partner?

A) -I
B) -Br
C) -Cl
D) -F
E) -OTf

Question 70

Draw the product(s) of the following reaction:

Question 71

What is the product in the following reaction?

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

Question 72

In a total synthesis of the bisnortriterpenoid rubriflordilactone A, a key step involved the following transformation. Draw the product. (J. Am. Chem. Soc. 2014, 136, 16477).

Question 73

Which of the following is a boronic acid?

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

Question 74

Draw the product(s) of the following reaction:

Question 75

Treatment of chloroform (CHCl₃) with strong bases results in _______ which is mechanistically described as a_______.

A) α-elimination; loss of leaving group followed by deprotonation.
B) α-elimination; deprotonation followed by a loss of leaving group.
C) β-elimination; deprotonation followed by loss of leaving group.
D) β-elimination; concerted deprotonation and loss of leaving group.

Question 76

What is the product of the following reaction?

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

Question 77

Which of the following is not a mechanistic step in the generally accepted mechanism of the Stille coupling?

A) transmetallation
B) reductive elimination
C) syn-elimination
D) oxidative addition

Question 78

Which of the following is a boronic ester?

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

Question 79

Biselyngbyolide A is a cytotoxic natural product that shows promise for the treatment of bone lytic diseases. Shown below is a recent synthesis of this molecule (Org. Lett. 2014, 16, 2858). Give the structure of intermediate 1 and Biselyngbyolide
A. Hint: PPTS is a strong organic acid.

Question 80

A total synthesis of ingenol utilized a dibromocyclopropanation via a carbene intermediate (J. Am. Chem. Soc. 2002, 124, 9726). What key type of reagent is missing from the reaction conditions?

A) Bronsted Acid
B) Bronsted Base
C) radical initiator
D) Lewis Acid catalyst