In the cyclic structure of fructose, the anomeric carbon is:

Step-by-step solution

Fructose is a ketohexose with its carbonyl group located at the second carbon atom (C-2) in the open-chain structure. During the formation of its cyclic structure, the hydroxyl group at C-5 or C-6 undergoes an intramolecular nucleophilic addition to the carbonyl carbon at C-2. This reaction converts the C-2 carbon into a hemiketal carbon, creating a new chiral center. The carbon atom that becomes a new stereocenter upon cyclization is known as the anomeric carbon. Therefore, the anomeric carbon in the cyclic struct