Question 1

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

Accepted Answer

The electronegative oxygen withdraws electron density, making the carbonyl carbon partially positive.

Question 2

Which reagent is most selective for reducing aldehydes and ketones, but not esters or carboxylic acids?

Accepted Answer

NaBH4

Question 3

What is the product when a Grignard reagent reacts with formaldehyde followed by aqueous workup?

Accepted Answer

A primary alcohol

Question 4

Which of the following best describes the geometry of the carbonyl carbon in aldehydes and ketones?

Accepted Answer

Trigonal planar

Question 5

Why are aldehydes generally more reactive than ketones toward nucleophilic addition?

Accepted Answer

Aldehydes have less steric hindrance and a more positive carbonyl carbon.

Question 6

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

Accepted Answer

PCC (Pyridinium chlorochromate)

Question 7

What is the major product when methylmagnesium bromide reacts with acetone followed by water?

Accepted Answer

tert-butanol

Question 8

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

Accepted Answer

$$R-X + 2Li \rightarrow R-Li + LiX$$

Question 9

Which organometallic reagent is best for performing a 1,4-conjugate addition to an α,β-unsaturated carbonyl compound?

Accepted Answer

Gilman reagent ($$R_2CuLi)$$

Question 10

What is the product of the following reaction: $$CH_3CH_2MgBr ($$Grignard) + $$CH_3COCH_3 ($$acetone) followed by $$H_2O$$?

Accepted Answer

tert-pentanol

Question 11

Which of the following is a correct statement about the use of protecting groups in organometallic chemistry?

Accepted Answer

Protecting groups prevent unwanted reactions with sensitive functional groups during organometallic reactions.

Question 12

Which of the following is the correct mechanism for the reaction of an organometallic reagent with an epoxide?

Accepted Answer

The nucleophile attacks the less hindered side of the epoxide, opening the ring.

Question 13

What is the product of the Wittig reaction between benzaldehyde and a methyl ylide?

Accepted Answer

Styrene ($$C_6H_5CH=CH_2$)

Question 14

Which of the following best describes the role of triphenylphosphine in the Wittig reaction?

Accepted Answer

It forms the ylide necessary for the Wittig reaction.

Question 15

Which of the following is a correct statement about the reduction of amides with LiAlH4?

Accepted Answer

Amides are reduced to amines.

Question 16

Which of the following is the correct product when DIBAL-H is used to reduce an ester at low temperature?

Accepted Answer

Aldehyde

Question 17

Which of the following reactions is used to synthesize a ketone from an acid chloride?

Accepted Answer

Friedel-Crafts acylation

Question 18

What is the major product when 2 equivalents of methyl lithium react with carbon dioxide followed by acid workup?

Accepted Answer

Acetic acid after hydrolysis ($$CH_3COOH)$$

Question 19

Which of the following is true about the reactivity of carbonyl compounds toward nucleophilic addition?

Accepted Answer

Steric hindrance decreases reactivity.

Intro to Organometallics & Reactions of Aldehydes and Ketones

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