Questions dealing with aldehydes and ketones

1. Outline a synthesis of the following compounds starting from either benzene or toluene:
1. n-butylbenzene



2. 1-phenyl-2-propanone

 



3. p-nitrobenzaldehyde



  

2. Outline a synthesis of 3-hexene from propane.



3. Bombykol, the sex pheromone of the silkworm moth, has been prepared in the following way:

 

1-pentyne + n-C₄H₉MgBr ® CH₃CH₂CH₂CºCMgBr

 A + HCHO; then H⁺ ® CH₃CH₂CH₂Cº CCH₂OH

B + PBr₃ ® CH₃CH₂CH₂CºCCH₂Br

 C + Ph₃P, base ® CH₃CH₂CH₂CºCCH=PPh₃

 D + OHCCH₂(CH₂)₇CO₂C₂H₅ ® CH₃CH₂CH₂CºCCH=CHCH₂(CH₂)₇CO₂C₂H₅

E + H₂/Pd ® CH₃CH₂CH₂CH=CHCH=CHCH₂(CH₂)₇CO₂C₂H₅ (cis)

F + LiAlH₄ ® CH₃CH₂CH₂CH=CHCH=CHCH₂(CH₂)₇CH₂OH (cis)

 

4. Propose a mechanism for the following reaction:



 

5. Compound "A", C₆H₁₂O₂, was found to be optically active. Reaction with Tollens reagent gave "B", C₆H₁₂O₃, an optically active carboxylic acid. (A must be an aldehyde!) Oxidation of "A" by pyridinium chlorochromate in dichloromethane gave an optically inactive compound which reacted with Zn(Hg)/HCl to give 3-methylpentane. Vigorous oxidation of "A" yielded "C", C₆H₁₀O₄, an optically inactive dicarboxylic acid. Give the structures of compounds "A", "B", and "C".

 A must have the 3-methylpentane carbon skeleton.

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