[PaulSzczesniak]

The first reaction linked I believe is a reverse acid catalyzed hydration but every time I try it (to try the reaction as if my product in the problem were my starting material) I get OH with two methyl groups. I've attempted hydride shifts and methyl shifts. I'm having a lot of trouble with it. The next two I simply have no idea where to start. I feel like the methylene cyclohexane problem resembles a dehydrohalogenation but they usually begin with a halogen on a single bond. Must I react the cyclohexane first with the chloroform and then do the b-elimination? The problem that has phenyl groups I've stared at and looked around my notes for a good hour and a half, I can't find anything. I appreciate the help in the meantime.

[discodermolide]

The first, do as it says, see where you can loose water and what structure do you get?
The second: elimination reaction, what are the prerequisites for this to happen?
The third: look up dichlorocarbene

[PaulSzczesniak]

The first, do as it says, see where you can loose water and what structure do you get?
The second: elimination reaction, what are the prerequisites for this to happen?
The third: look up dichlorocarbene

I got the first one, I was being silly. The second one I'm still working on but a quick question about it, would the Br AND the Oxygen (with a methyl group attached) both be eliminated or just the Br)? The third I believe to be a cyclohexane ring with a "wedged" hydrogens on both sides of the double bond, and two "dashed" bonds towards an extended carbon (not part of ring) which is then singly bonded to two Chlorines.

[PaulSzczesniak]

The first, do as it says, see where you can loose water and what structure do you get?
The second: elimination reaction, what are the prerequisites for this to happen?
The third: look up dichlorocarbene

I think for problem two, since it's a bulky base, the elimination cannot begin with the two hydrogens that would form the Zaistev product. Instead it must attack an external hydrogen, my new question to you is, can it attack the methyl group attached to the Oxygen? My guess is no since that would not form a C-C double bond. So I believe it would attack the phenyl groups. Is this even possible?

[discodermolide]

Just loose HBr from the starting product. But remember to rotate the molecule so that the H and Br are trans peri-planar and you end up with the correct olefin geometry.

The third one, you generate dichlorocarbene :CCl₂ which reacts with a C=C to give???

[PaulSzczesniak]

Just loose HBr from the starting product. But remember to rotate the molecule so that the H and Br are trans peri-planar and you end up with the correct olefin geometry.

The third one, you generate dichlorocarbene :CCl₂ which reacts with a C=C to give???

I feel confident with my results. I will see how well my answers compare when we review this back test in tomorrow's exam review. I appreciate your time, many thanks.

[discodermolide]

Do you wish to share them here?

[PaulSzczesniak]

Do you wish to share them here?

The aldehyde is part of a different reaction involving a terminal alkyne attached to a cyclohexane reacting with 1) (sia)2 BH 2)H2O2, NaOH...

[discodermolide]

The third compound on that last post is incorrect.
You eliminate HBr. To eliminate HBr the H and the Br must be in a trans antiperiplanar arrangement to each other.
This suggests that you will obtain a certain geometry of the new C=C. This is what you need to work out.

[PaulSzczesniak]

The third compound on that last post is incorrect.
You eliminate HBr. To eliminate HBr the H and the Br must be in a trans antiperiplanar arrangement to each other.
This suggests that you will obtain a certain geometry of the new C=C. This is what you need to work out.

[discodermolide]

Don't think the olefin stereochemistry is correct.
To eliminate HBr the H and the Br must be in a trans antiperiplanar arrangement to each other.
Can you make a model?