Q54 E_b. - Organic Chemistry (Mcmurry)

Question

Ribose, an essential part of ribonucleic acid (RNA), has the following structure:

(a) How many chirality centers does ribose have? Identify them.

(b) How many stereoisomers of ribose are there?

(c) Draw the structure of the enantiomer of ribose.

(d) Draw the structure of a diastereomer of ribose.

Step-by-Step Solution

Answer

(b) There are eight stereoisomers of ribose.

Stereoisomers

Stereoisomers are compounds with the same molecular formula but have different configurations. The formula used for calculating the number of stereoisomers is . Here, n is the number of stereogenic centers present in a molecule.

The number of stereoisomers of ribose

(b) The numbers of stereoisomers of ribose are eight, and these are obtained by formula, where n is the number of chiral centers in a molecule.

$$\begin{gathered} \text{Number} \text{of} \text{stereoisomers}={\text{2}}^{\text{n}} \\ =2^3 \\ =8 \end{gathered}$$