Question 1

Which statement best explains why the carbonyl carbon in aldehydes and ketones is susceptible to nucleophilic attack?

Accepted Answer

The carbonyl carbon is partially positive due to the electronegative oxygen, making it an electrophile.

Question 2

Which of the following carbonyl compounds is most reactive toward nucleophilic addition?

Accepted Answer

Formaldehyde

Question 3

What is the correct IUPAC name for the following structure: $$\mathrm{CH_3CH_2COCH_3}$$?

Accepted Answer

Butan-2-one

Question 4

Why are more substituted carbonyls less reactive toward nucleophilic attack?

Accepted Answer

Steric hindrance prevents nucleophiles from approaching the carbonyl carbon.

Question 5

Which reagent would selectively reduce an aldehyde to a primary alcohol without affecting an ester group?

Accepted Answer

NaBH4

Question 6

What is the product of the reaction between methylmagnesium bromide ($$\mathrm{CH_3MgBr}) $$and formaldehyde ($$\mathrm{H_2C=O}) $$followed by acidic workup?

Accepted Answer

Ethanol ($$\mathrm{CH_3CH_2OH})$$

Question 7

Which organometallic reagent is best for performing a nucleophilic substitution (S$$_N2) on a $$primary alkyl halide?

Accepted Answer

Gilman reagent ($$\mathrm{R_2CuLi})$$

Question 8

What is the major product when a Gilman reagent ($$\mathrm{(CH_3$)_2CuLi}) $$reacts with 1-bromo-2-phenylethene ($$\mathrm{C_6H_5CH=CHBr}$$)?

Accepted Answer

1-methyl-2-phenylethene

Question 9

Which statement about the reaction of organometallic reagents with epoxides is correct?

Accepted Answer

The nucleophile attacks the less hindered side of the epoxide.

Question 10

What is the role of a protecting group in reactions involving organometallic reagents?

Accepted Answer

To prevent unwanted reactions with protic functional groups.

Question 11

Which of the following is a correct mechanism for the formation of a hemiacetal from an aldehyde and an alcohol under acid catalysis?

Accepted Answer

Protonation of the aldehyde, followed by nucleophilic attack by the alcohol.

Question 12

Which reagent is commonly used to oxidize a primary alcohol to an aldehyde without further oxidation to a carboxylic acid?

Accepted Answer

Pyridinium chlorochromate (PCC)

Question 13

What is the product of the reaction between a Grignard reagent and carbon dioxide ($$\mathrm{CO_2$}) $$followed by acidic workup?

Accepted Answer

Carboxylic acid

Question 14

Which statement best describes the Wittig reaction?

Accepted Answer

It replaces a carbonyl group with an alkene using a phosphonium ylide.

Question 15

Which of the following is a correct general reaction for the preparation of an organolithium reagent?

Accepted Answer

$$\mathrm{R-X + 2Li \rightarrow R-Li + LiX}$$

Question 16

Why are organometallic reagents typically prepared in diethyl ether?

Accepted Answer

Diethyl ether is aprotic and prevents protonation of the organometallic reagent.

Question 17

Which of the following best describes the difference between 1,2- and 1,4-addition to α,β-unsaturated carbonyl compounds?

Accepted Answer

1,2-addition occurs at the carbonyl carbon, while 1,4-addition occurs at the β-carbon.

Question 18

Which organometallic reagent is most likely to perform a 1,4-addition to an α,β-unsaturated carbonyl compound?

Accepted Answer

Gilman reagent ($$\mathrm{R_2CuLi})$$

Organometallics and Reactions of Aldehydes & Ketones: Structure, Reactivity, and Nomenclature

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