How many stereoisomers are there in a 2-ketohexose?

Question

Quizplus · Accepted Answer

A 2-ketohexose has six carbons and a ketone group on the second carbon. There are two possible configurations for the hydroxyl groups on each carbon, giving 2^6 = 64 possible stereoisomers. However, because of the presence of a ketone group, there is a plane of symmetry between the second and third carbons, which reduces the number of stereoisomers by half, leaving 32 possible stereoisomers. Additionally, the stereoisomers that are mirror images of one another are considered to be identical. Therefore, the actual number of stereoisomers is 32/2 = 16.

How Many Stereoisomers Are There in a 2-Ketohexose