All right. So let's start off with the first step. HBr. We know that the O is going to protonate. So what I'm going to wind up getting is a protonated ether with a formal charge. And I also get this awesome nucleophile Br-. So the next step needs to be a backside attack. I'm going to go ahead and pick one of the sides, doesn't matter which one, to attack and kick out the good leaving group, which in this case is going to be a neutral alcohol.
So what I'm going to wind up getting now is something that looks kind of funny. It's going to break open the ring. So I'm going to get a bromine up here, and then I'm going to get the same ring as before and then I'm going to get OH. Just to make sure, let's check that there's the same number of carbons. 1, 2, 3, 4. Yes, we drew it correctly. Now keep in mind that we don't ha