Question

to form pyranose the hydroxyl group from which position of an aldohexose attacks the carbonyl carbon

Answer 1

To form the pyranose, the hydroxyl group at the fifth (5) position of an aldohexose attacks the carbonyl carbon.

• The hydroxyl at the 5 position forms a hemiacetal with the aldehyde at the position one (1).

• In other words, the pyranose ring structure is formed due to hemiacetal formation between C₁ and C₅ carbon atoms.