Question

The possible number of stereoisomers for 5-phenylpent-4-en-2-ol is:
 

Hint:

For molecules with two chiral centers, use the \(2^n\) rule to calculate the maximum number of stereoisomers, where \(n\) is the number of chiral centers. Then check for symmetry to reduce the number of distinct stereoisomers.

Answer 1

Step 1: The given compound is \(5\)-phenylpent-4-en-2-ol. This is a compound with one chiral center at \(C_2\) and one at \(C_4\), which means it can form stereoisomers. 

Step 2: Since the structure is of an alkene (with a double bond) at the position 4, and the hydroxyl group (\(OH\)) at position 2, the molecule can form cis and trans stereoisomers depending on the orientation of the substituents about the double bond. 

Step 3: There are two chiral centers in the molecule. For each chiral center, there are two possibilities (R or S), leading to a total of \(2^2 = 4\) stereoisomers. However, the molecule also has a plane of symmetry due to the phenyl group, which reduces the total number of stereoisomers. 

Step 4: Hence, the molecule has only 2 stereoisomers.