Question 1

Which of the following statements best explains why Grignard reagents must be prepared and used under anhydrous conditions?

Accepted Answer

Grignard reagents are strong nucleophiles and will react with water to form alkanes, destroying the reagent.

Question 2

What is the major organic product when phenylmagnesium bromide reacts with acetone, followed by aqueous workup?

Accepted Answer

1-phenylpropan-2-ol

Question 3

Which of the following carbonyl compounds will react with two equivalents of a Grignard reagent to yield a tertiary alcohol after hydrolysis?

Accepted Answer

Ester

Question 4

Which equation correctly represents the formation of an organolithium reagent from an alkyl halide?

Accepted Answer

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

Question 5

Which of the following statements about Gilman reagents is TRUE?

Accepted Answer

Gilman reagents react efficiently with alkyl halides to form coupled products.

Question 6

Which of the following best describes the product of the reaction between a terminal alkyne and sodium amide ($$NaNH_2$$)?

Accepted Answer

A sodium acetylide ($$R-C\equiv C$$^{-}$$Na^{+}$)

Question 7

Which reagent would you use to reduce an ester to a primary alcohol?

Accepted Answer

Lithium aluminum hydride ($$LiAlH_4)$$

Question 8

Which of the following reactions will NOT occur with a Grignard reagent?

Accepted Answer

Addition to a carboxylic acid

Question 9

What is the product of the reaction between butane-1-thiol ($$CH_3CH_2CH_2CH_2SH) $$and another equivalent of butane-1-thiol in the presence of an oxidizing agent?

Accepted Answer

Disulfide ($$CH_3CH_2CH_2CH_2S-SCH_2CH_2CH_2CH_3)$$

Question 10

Which of the following statements about thiols is CORRECT?

Accepted Answer

Thiols are more acidic than alcohols due to the lower electronegativity of sulfur.

Question 11

A student attempts to synthesize a Grignard reagent from 1-bromo-4-fluorocyclohexane in tetrahydrofuran (THF). Which of the following is the expected product?

Accepted Answer

4-fluorocyclohexylmagnesium bromide

Question 12

Which of the following best explains why sodium borohydride ($$NaBH_4) is $$less reactive than lithium aluminum hydride ($$LiAlH_4$$)?

Accepted Answer

$$NaBH_4 is $$less nucleophilic and cannot reduce esters or carboxylic acids.

Question 13

Which of the following is a correct statement about the reaction of Grignard reagents with epoxides?

Accepted Answer

Grignard reagents open the epoxide ring to form a primary alcohol after hydrolysis.

Question 14

Which of the following is the correct product when an organolithium reagent reacts with an alkyl halide?

Accepted Answer

A coupled alkane

Question 15

Which of the following is a side reaction that can occur during Grignard reagent synthesis?

Accepted Answer

Self-coupling of the Grignard reagent to form a dimer

Question 16

Which of the following equations represents the reduction of a ketone to an alcohol using sodium borohydride?

Accepted Answer

$$R_2C=O + $$NaBH_4$$ \rightarrow R_2CHOH$$

Question 17

Which of the following functional groups will NOT be reduced by sodium borohydride ($$NaBH_4$$)?

Accepted Answer

Ester

Question 18

Which of the following is a correct statement about the acidity of terminal alkynes?

Accepted Answer

Terminal alkynes are more acidic than alkanes due to the sp-hybridized carbon.

Question 19

Which of the following is the correct product when a Grignard reagent reacts with formaldehyde, followed by aqueous workup?

Accepted Answer

A primary alcohol

Organometallic Reagents and Carbonyl Chemistry (CHM-232: Chapter 10E)

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