Question

How can I draw all possible stereoisomers for 1,3-dibromopentane?

Answer 1

Identify the chiral centres, then draw all possible answers.

Explanation:

Step 1. Draw the bond-line structure for 1,3-dibromopentane.

Step 2. Identify the chiral centres.

The only chiral centre is `"C-3"`.

Step 3. Calculate the number of possible stereoisomers.

The maximum number of stereoisomers is `2^n`, where `n` is the number of chiral centres.

Here, `n=1` and `2^1 =2`, so there are two possible stereoisomers.

Step 4. Draw the stereoisomers.

If we indicate the stereochemistry of the bonds to the heteroatoms by wedges and dashes, the structures are

Step 5. Check for meso isomers.

There is no internal plane of symmetry, so there are no meso isomers.

The above structures are both unique stereoisomers.