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Aldehydes and Ketones: Synthesis and Nucleophilic Additions (Worksheet)

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Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.

Q1

Identify the nucleophile and the electrophile for each reaction and briefly explain why reaction B does not react but A and C do.

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Q2

Write detailed electron-pushing mechanisms that explain the stated observations.

a. The following reaction occurs rapidly at pH = 5, but fails at pH = 1. 

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b. The labeling of acetone with 18O is catalyzed by both acid and base.

 

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Q3: Propose structures for the lettered compounds

Compound A, C9H12O, was optically active, did not give a precipitate with 2,4‑dinitrophenylhydrazine [indicates that it is not an aldehyde or ketone], showed a broad IR band at 3400 cm–1, and was readily oxidized to B, C9H10O, with aqueous chromic acid (H2CrO4) at room temperature. When A was refluxed with chromic acid, benzoic acid was obtained. Compound B showed strong IR absorption at 1670 cm–1 but none at 3400 cm–1 and reacted with 2,4-dinitrophenylhydrazine reagent to give C. When B was reacted with EtMgBr followed by aqueous workup, compound D was obtained. D did not react with chromic acid reagent at room temperature and showed an IR band at 3400 cm–1. B and D were optically inactive and could not be resolved.

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Q4

Complete the following Table A through H. showing a synthesis using for each. You may use any necessary organic and inorganic reagents. More than one step may be required.

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