All right guys, I'm going to go ahead and draw the mechanism for this, and I am going to abbreviate a few steps because this doesn't say draw the whole mechanism. It says predict the product. So, what we're going to do is I'm going to simplify stuff so that you guys can get the point. We're not going to draw every single step. In the protection step, we know that my TBDMS—wow man, I'm dyslexic here—TBDMS is going to react with the OH. So I just know that my O is going to grab TBDMS, and what I'm going to wind up getting is a protected version of the alcohol that looks like this. Now, if I wanted to draw that whole thing out, I could. That just stands for the oxygen attached to the silyl ether. Is that cool? Awesome.

So now that I've got that, what does that mean? It's protected now. Nothing can react with the O and the TBDMS on it. So now I can do my actual reaction. Well, do you guys know what kind of reaction this would be? It would be a reaction of my double bond with HBr. This is going to be a hydrohalogenation. This is the most basic addition reaction. So, I go ahead and I grab my H, kick out the Br. What I wind up getting is something that looks like this, OTBDMS. Wow, I keep doing the M first. And now I'm going to have a carbocation right here according to Markovnikov's rule. So, now what's going to happen? Well, actually this is a carbocation that wants to shift. So you really have to do the whole reaction. We're going to want to do a shift here. What kind of shift? A hydride shift. Why? Because there's a hydride in the position that is more stable. Okay? So I go ahead and I do an H shift. I've got an H here. It moves over, and what I wind up getting is OTBDMS with now a carbocation here. Now that carbocation is actually stable. So now I can react with the Br negative and attack. What that's going to give me is OTBDMS and my bromine right here. So now I've got the actual target molecule. I reacted the little one with the HBr. I got my alkyl halide, but I don't want to end up with OTBDMS. What the heck is that? You want to take it off.

So in the last step, we use F negative. Remember F negative is the thing that attacks. To attack, kick out the O and then HCl will protonate it. So what we wind up getting at the end of this, and I don't have a whole lot of room to write, so I'm going to try to fit it in here. I'm sorry, my head's in the way too. But What we're going to wind up doing, I'm going to draw it up here if you guys don't mind. What we're going to get is something that looks like this: O-methyl Br like that. This is our final product because we're regenerating the alcohol, and we reacted with the double bond and we got our halogen. So, this would be the final answer to this question and it used the method of protection, reaction, and then deprotection. So that's always going to be kind of the method that we use. I hope that made sense. Let me know if you have any questions, but if not, let's go ahead and move on.