Draw the structure of an eight-carbon alkene that would yield the following compound (and no others) after treatment with ozone followed by dimethyl sulfide.
The correct answer and explanation is :
To determine the structure of the eight-carbon alkene that undergoes ozonolysis followed by reduction with dimethyl sulfide (Me(_2)S), we follow these steps:
Step 1: Understanding Ozonolysis
Ozonolysis cleaves double bonds in alkenes, forming carbonyl compounds. The specific products obtained help in deducing the structure of the original alkene.
Step 2: Identifying the Cleavage Pattern
The question states that the given alkene yields only one compound after ozonolysis. This suggests that the alkene is symmetrically structured, or that the two resulting carbonyl fragments are identical or connected.
Step 3: Possible Eight-Carbon Alkenes
The molecular formula for a simple eight-carbon alkene is C(_8)H(_{16}). The most common structural possibilities include:
- Straight-chain alkenes (e.g., oct-2-ene, oct-3-ene)
- Branched alkenes (e.g., 2,3-dimethylhex-2-ene)
- Cyclic alkenes (e.g., cyclooctene)
Step 4: Finding a Structure Yielding a Single Product
To obtain a single carbonyl compound upon cleavage, the alkene must be symmetrical. The best candidate is 4-octene, which is structured as follows:
[
CH_3CH_2CH=CHCH_2CH_2CH_3
]
Upon ozonolysis:
[
CH_3CH_2CH=CHCH_2CH_2CH_3 + O_3 \to 2CH_3CH_2CHO
]
This reaction produces only butanal (butyraldehyde), confirming that 4-octene is the correct structure.
Conclusion
The correct answer is 4-octene. Since it is symmetrical around the double bond, cleavage results in only one carbonyl compound. Other isomers would produce two different carbonyl compounds.