Two stereoisomers of 1-bromo-4-methylcyclohexane are formed when trans-4-methylcyclohexanol reacts with hydrogen bromide. Write structural formulas of:
Hey everyone. So, in this reaction our trans 4-methyl cyclohexanol it's going to react with hydrogen bromide to give us 2 different stereoisomers and for this point of our question in Part A what we need to show is simply the structural formula of our trans 4-methyl cyclohexanol and we're going to show it the most stable form. Now, since we have a cyclohexane as our root we know that a six membered ring can either exist in the regular planar structure that can be a six membered ring or you can show it any chair conformation, which we're going to show by drawing two parallel lines like this where one of them starts in the middle of the other and then we draw these points up and down to join chair conformation. So, this chair conformation is the one we're going to draw for our trans 4-methyl cyclohexanol. Now, we know that there's going to be an alcohol group because of that ol at the end and say we picked this to be number one, we can have an OH there and we also need to have a methyl group at position 4 CH3. Now, they are trans to each other, so we need to draw one on a wedge and the other one on a dash, okay? let's refill in our ring here, with position 1 and now let's show this a OH on a dash, alright? So, in the most stable chair conformation since they're trans we actually had both of the groups equatorial here, where say we started out with our alcohol, it can face down and our chair conformation, this is going to be down and equatorial. Now, our other group, our methyl, needs to face up because they're trans, so we're having methyl facing up and it looks like the O position if this is position 1 we can go 2, 3 and 4 facing up, we can have another methyl group and it's going to be equatorial as well, so they're both going to be in the equatorial position, which is more favorable, so this is going to be our formula for our trans 4-methyl cyclohexanol. Alright and if you need any help with drawing your chair conformation feel free to watch our video that talks about drawing your chair positions, okay? your equatorial and axial. Alright guys I hope this made sense and let me know if you have any questions.