Question

How can I draw a perspective formula for ( R )-1,2-dibromobutane?

Answer 1

Here's the method I would use.

Explanation:

Step 1. Draw the butane chain.

Butane chain

Step 2. Add wedges and dashes to `"C-1"` and `"C-2"`.

Wedge-dash

Step 3. Add the `"Br"` to the solid bond and `"H"` atoms to the other bonds of `"C-1"`.

1-bromo

Step 4. Arbitrarily add the second `"Br"` to the wedge on `"C-2"` and `"H"` to the dash (I have a 50:50 chance of getting it right).

1,2-dibromobutane

Step 5. Assign stereochemistry to `"C-2"`.

This is the `S` structure. I got it wrong!

The correct structure must be

Correct