What is the total number of chiral carbons present in glucopyranose and fructofuranose respectively?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 5 and 4
Let’s count the chiral (asymmetric) carbon atoms in each cyclic sugar.
Glucopyranose
- Open-chain glucose has 4 chiral carbons (C2–C5).
- On cyclisation to glucopyranose, C1 (anomeric carbon) also becomes chiral.
- Total chiral carbons = 5
Fructofuranose
- Open-chain fructose has 3 chiral carbons (C3–C5).
- On cyclisation, C2 (anomeric carbon) becomes chiral.
- Total chiral carbons = 4