Chemistry - ALCOHOL & ETHER Question with Solution | TestHub
Consider the following reaction sequence and answer the given questions :
Which is the best possible structure of X from the given compounds :
Options:
Answer:
Solution:
Explain Question:
The question asks to identify the structure of an optically active ether "X" (C5H10O) that eventually
forms a conjugated diene "Z".
Concept: Ether Cleavage, Optical Activity, Dehydrohalogenation
Solution:
• Step 1: Ether "X" (C5H10O) reacts with excess HI to form a diiodide "Y" (C5H10I2 ).
Both X and Y must be Optically Active (possess a chiral center).
• Step 2: "Y" reacts with alcoholic KOH to form a conjugated diene "Z" (C5H8 ).
• Option 1: 2-methyltetrahydrofuran is chiral. Cleavage with HI gives 1,4-diiodopentane, which is also chiral. Elimination of 1,4-diiodopentane yields 1,3-pentadiene, a Conjugated Diene
• Option 2: Tetrahydropyran is achiral.
• Option 3: 2,2-dimethyloxetane is achiral.
• Option 4: 2-ethyl-2-methyloxirane is chiral, but its diiodide would not easily yield a 5-carbon
conjugated diene through standard elimination.
