How can I draw all possible stereoisomers for 2-bromo-4-chlorohexane?

1 Answer
Aug 27, 2015

Identify the chiral centres and then draw all the possibilities.

Explanation:

Step 1. Draw the bond-line structure for 2-bromo-4-chlorohexane.

Bond-LineBond-Line

Step 2. Identify the chiral centres.

The chiral centres are "C-2"C-2 and "C-4"C-4.

Step 3. Calculate the number of possible stereoisomers.

The maximum number of stereoisomers is 2^n2n, where nn is the number of chiral centres.

Here, n=2n=2. and 2^2 =422=4, so there are four 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

Wedge-WedgeWedge-Wedge

Wedge-DashWedge-Dash

Dash-WedgeDash-Wedge

Dash-DashDash-Dash

Step 5. Check for meso isomers.

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

The above structures are all unique stereoisomers.