Question

I need help with this organic chemistry problem, literally spent 4 hours on it and i dont understand how the book got the answer

How do I get the R&S for trans-1,2-dichlorocyclopentane?

I am getting confused because it has 2 chlorines and I dont know how to work it out.

Answer 1

There's a little trick, when you have an H, put that at the back, like if you had:

So for your compound, the carbon on the right is S:



I think you're getting confused in the ordering of priority (Cahn-Ingold-Prelog). You should review the rules form your textbook.