Which of the following is the correct structure of L -fructose?
(A)(see structure)
(B)(see structure)
(C)(see structure)✓ Correct
(D)(see structure)
Answer: (C)
Solution
Fructose is a 2-ketohexose whose configurational label is fixed by the lowest stereocentre, C-5. In the Fischer projection of D-fructose the C-5 hydroxyl lies on the right, with the C-3 hydroxyl on the left and the C-4 hydroxyl on the right. The L-isomer is the complete mirror image, so every stereocentre inverts: the C-3 hydroxyl moves to the right, the C-4 hydroxyl to the left and the C-5 hydroxyl to the left, keeping the ketone at C-2. This arrangement, C-3 OH right, C-4 OH left and C-5 OH left, is L-fructose.
JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Single correct option
