What is the relationship between D-erythrose and D-threose?

Question

Quizplus · Accepted Answer

D-erythrose and D-threose differ in the configuration (R or S) at one of the chiral centers, but not at the other. Therefore, they are diastereomers. They are not constitutional isomers (A) because they have the same molecular formula and the same connectivity of atoms. They are not enantiomers (B) because they do not have opposite configurations at all chiral centers. They are not tautomers (D) because they do not undergo a chemical reaction involving the migration of a hydrogen atom and a double bond.

What Is the Relationship Between D-Erythrose and D-Threose