Question

How can I convert R-2-bromopentane to a Fisher projection?

Answer 1

Step 1. Draw the bond-line structure of 2-bromopentane.

Step 2. Convert this to a wedge-dash structure.

(a) Start by making the Br bond a wedge and the H bond a dash. We have a 50 % chance of getting it right.

(b) Assign configurations. This is the `R` isomer. We got it right!

Step 3. Draw the skeleton Fischer projection

To convert this to a Fischer projection, draw a vertical line of five carbon atoms, with C-1 at the top and a cross at C-2.

Step 4. Attach the H and the Br atoms to the correct sides of the cross.

We must look at the molecule from the upper right. This puts Br on the left and H on the right.

And we have our structure.