FINAL: Chapter 20

What is the missing reagent in the reaction below? A. NaBH4/CH3OH B. DIBAL-H C. H2, Pd-C D. LiAlH4 then H2O

D

What is the product of the following reaction? A. I B. II C. III D. Only I and II

D

Rank the carbon-metal bond in the following organometallic reagents in order of decreasing polarity, starting with the most polar.

II > I > III

Rank the following compounds in order of increasing reactivity (least to most reactive) with respect to acyl substitution. I. methyl benzoate II. benzoylchloride III. benzamide

III < I < II

If the starting material has no stereogenic centers, when carbonyl compounds are reduced with a reagent such as LiAlH4 or NaBH4 and a new stereogenic center is formed, what will the composition of the product mixture be? A. Forms a racemic mixture of the two possible enantiomers B. Forms more of one enantiomer than another because of steric reactions around the carbonyl C. Forms more of one enantiomer than another depending on the temperature of the reaction D. Forms different products depending on the solvent used

A

The behavior of acid chlorides is different from that of aldehydes in a reaction with a nucleophile because A. The acid chloride contains a better leaving group. B. The aldehyde is more easily oxidized. C. The carbonyl of the aldehyde is more positive. D. The carbonyl of the aldehyde is less hindered.

A

What is the major organic product of the following reaction? A. I B. II C. III D. IV

A

What is the major organic product of the following reaction? A. I B. II C. III D. IV

A

What is the missing reagent in the reaction below? A. Et2CuLi then H2O B. EtMgBr then H2O C. NaBH4/CH3OH D. H2, Pd-C

A

What is the missing reagent in the reaction below? A. [1] Mg, [2] CO2, [3] acidic work-up B. [1] CO2, [2] NaOH C. [1] CO2, [2] acidic work-up D. LiAlH4

A

What is the major organic product of the following reaction? A. I B. II C. III D. IV

D

What is the major organic product in the following sequence of reactions? A. I B. II C. III D. IV

B

A carbonyl group, C=O, and an alkene, C=C, double bonds are both sp2 hybridized. However, the chemistry of these two functional groups is very different. This can be explained by which of the following statements? A. The bond angle of the carbonyl is larger than the bond angle of the alkene. B. The electronegative oxygen of the C=O group makes this bond polar. C. The bond of the C=C is longer that the bond of the C=O. D. There is more steric crowding in the carbonyl than in the alkene.

B

What is the major organic product of the following reaction? A. I B. II C. III D. IV

B

What is the missing reagent in the reaction below? A. [1] LiAlH4, [2] H2O B. [1] CH2=CHLi, [2] H2O C. [1] (CH2=CH)2CuLi, [2] H2O D. [1] DIBAL-H, [2] H2O

B

What is the missing reagent in the reaction below? A. [1] LiAlH4, [2] H2O B. [1] CH3MgBr (excess), [2] H2O C. [1] (CH3)2CuLi (excess), [2] H2O D. [1] DIBAL-H, [2] H2O

B

What is the product of the following reaction? A. I B. II C. III D. IV

B

What is the starting material in the reaction below? A. Bromobenzene B. Benzyl bromide C. Benzoic acid D. Lithium benzoate

B

Both LiAlH4 and NaBH4 are reducing agents. Which statement about these reagents is true? A. Both reagents contain polar metal-hydrogen bonds. The polarity of the B-H bond is greater than the polarity of the Al-H bond, so LiAlH4 is the stronger reducing agent. B. Both reagents contain polar metal-hydrogen bonds. The polarity of the B-H bond is greater than the polarity of the Al-H bond, so LiAlH4 is the weaker reducing agent. C. Both reagents contain polar metal-hydrogen bonds. The polarity of the B-H bond is less than the polarity of the Al-H bond, so LiAlH4 is the stronger reducing agent. D. Both reagents contain polar metal-hydrogen bonds. The polarity of the B-H bond is less than the polarity of the Al-H bond, so LiAlH4 is the weaker reducing agent.

C

What is the major organic product of the following reaction? A. I B. II C. III D. IV

D

What is the major organic product of the following reaction? A. I B. II C. III D. IV

C

What is the missing reagent in the reaction below? A. NaBH4/CH3OH B. H2, Pd-C C. LiAlH4 then H2O D. MeMgBr then H2O

C

What is the missing reagent in the reaction below? A. PhMgBr then H2O B. Benzene, AlCl3 C. Ph2CuLi then H2O D. PhLi then H2O

C

What is the product of the following reaction? A. I B. II C. III D. IV

C

Rank the following compounds in order of increasing reactivity toward the nucleophilic hydride reagent, NaBH4. A. I < II < III B. III < II < I C. II < III < I D. II < I < III

D

What carbonyl compound and Grignard reagent could be used to prepare 2-butanol? A. Only I B. Only II C. Only III D. Only I and II

D

What is the major organic product in the following sequence of reactions? A. I B. II C. III D. IV

D

Which of the following statements about organometallic reagents is not true? A. Organometallic reagents contain a carbon atom bonded to a metal. B. The more polar the carbon-metal bond, the more reactive the organometallic reagent. C. Organometallic reagents react as bases and nucleophiles. D. Organometallic reagents are strong acids that readily donate a proton to water.

D