Question

Question: Referring to Figure 28.5, which d-ketohexoses have the S configuration at C3?

Fig. 28.5

Short answer

Answer

All the d-ketohexoses have the R configuration.

Step-by-step solution

d-Ketohexoses

Any monosaccharide that has six carbon atoms with a ketone functional group with three chiral centers that rotate is known as a d-ketohexose. Examples of d-ketohexoses include fructose, psicose, sorbose, and tagatose

Identifying configuration

Among the given d-ketohexoses, the C3 carbon atom is a chiral center. The Fischer projections are converted to the wedge and dash structures as follows.

From the wedge-dash structures, all the d-ketohexoses have the R configuration.

Wedge-dash structures of the given ketohexoses