The Cahn-Ingold-Prelog stereochemical designations used for the following substance are:
A)2R,4S
B)2S,4R
C)2R,4R
D)2S,4S
E)The "R,S" terminology doesn't apply in this case.

Question

The Cahn-Ingold-Prelog stereochemical designations used for the following substance are: 
A)2R,4S 
B)2S,4R 
C)2R,4R 
D)2S,4S 
E)The "R,S" terminology doesn't apply in this case.

Quizplus · Accepted Answer

The Cahn-Ingold-Prelog stereochemical designation of a molecule is based upon its functional groups, which are designated with letters such as R or S. The molecule shown is a diastereoisomer of the Fischer projection of glucose, and if we assign R or S to each chiral carbon based on the priority of the groups attached, we find that the molecule can be designated as 2R,4R. Both chiral centers have an R configuration based on the R priority of the hydroxyl groups. Thus, the correct answer is C) 2R,4R.

The Cahn-Ingold-Prelog Stereochemical Designations Used for the Following Substance Are