 Okay, so we learned how to do the syn-dial. We can use either osmium tetroxide or potassium permanganate and we can get the syn-dial. What we can also do is use different conditions to get the trans-dial from the alkene. So remember, this product here would come from using MCPVA on cyclo-texene. So you can go back over that mechanism on your own, but let's do the second part of the mechanism to get the trans-dial. So is everybody okay with thinking about this part? Can I just erase that? So I'm going to erase this, just like you should always do when you're about to write a mechanism and draw out your bonds. So H30 plus, well, what's going to happen? That's a strong acid. So you're going to have acid-base reaction, the fastest reactions in organic chemistry. So what's going to be the base, the oxygen on the epoxide? Is everybody okay with that? So what's going to happen, remember? The electrons grab the proton. That means that bond breaks there. That's the first step of the reaction. It's an acid-base reaction, so I'm actually going to put an equilibrium arrow. Now we have a protonated epoxide as our intermediate water. Of course, this acid is in a solution of some sort of alcohol or some sort of water. It's in the solution of water. So what's going to happen now is that that water is actually going to do an SN2 attack reaction on the cyclohexane or the epoxide ring there. So what will happen? Is there a little attack there? Okay, remember? It's got an attack from the antibonding orbital, so it's got to do that backside attack. Do you guys remember that? So what this is going to do, so once that bond is being formed, of course that bond has to break like that. We're going to get this reaction here, and this is actually the driving force for this reaction. So what's going to happen? We're going to have inversion of configuration at that stereocenter there. So the oxygen is going to now be on the backside, and the hydrogen is going to be flipped over. So let's draw that. Remember this is the Lewis acid and Lewis base, so they're going to stick together, and you want to show your hydrogens. Okay, remember this is in, like we said, there's a bunch of water. It's the solvent in this reaction. So what's going to happen? Another water molecule can become involved, and it's going to deprotonate that protonated alcohol there, and that's actually an management equilibrium, but then you just wash out all your alcohol and then you can work out. So from that reaction conditions, I can get that trans-style. So you guys see that they're on opposite sides of the ring there? Okay, so remember with osmium tetroxide, you can get the cis-style from the alkene, or the datacine permanganate. You can get the trans-style using MCPBI for your first step and then acid for your second step. You could also get it using a base for your second step, like we were talking about hydrogens. Any questions on this one? Wonderful.