[momoho]

What are the mechanisms for the reactions below?

[Borek]

Please read the forum rules.

You have to show your attempts at solving the question to receive help. This is a forum policy.

[zsinger]

Tricky mechanism on number one!  Heres a hint…..what would be the first step with a double bond full of electrons and a very good "H+" donor………hope this steers you on the right track.  Do you think that negative Oxygen or the alkene might suck up the proton first?  Food for thought.
             -Zack

[zsinger]

Additionally, try re-arranging the Carbocation once it is formed, taking into account both induction, AND sterics……why might the OH end up far away from the nitrogen double bond?

[momoho]

Tricky mechanism on number one!  Heres a hint…..what would be the first step with a double bond full of electrons and a very good "H+" donor………hope this steers you on the right track.  Do you think that negative Oxygen or the alkene might suck up the proton first?  Food for thought.
             -Zack

I don't get what you say yet.
Could you tell more description?

[orgopete]

1) Look up Nef reaction. I think a similar movement of electrons is occurring. Rather than water adding directly, try adding vinylogously to the aromatic ring. Let's see what you get.

2) Just protonate the double bond. Ring strain often motivates rearrangements. Try one.

[zsinger]

OK….I solved this whole thing out.  Here is another hint.  In the second one, how do you notice that the rear rings are forming.  You will notice that they are both composed from one carbon from the other two starting material rings.  This should indicate some sort of ring expansion to relieve torsional strain.  This problem, while difficult, is far from impossible.

Orgo,
Im not sure this is the Nef, although I know you are a much more knowledgable chemist than I.  Please do correct me if I am wrong.
     -Zack

[orgopete]

It isn't a Nef. At best it is an aza-vinylog of a Nef. However, I think you need to be able to draw the Nef mechanism or at least it would be helpful if you could, to be able to draw the mechanism for this reaction.

I was just trying to give a hint. I don't want to spoil the poster's fun in solving this problem. If this hint should not succeed, I can always give another hint that will bring the poster closer to the solution.

[zsinger]

aza-vinylog?  New terminology to me!  Like the aza-cope rearrangement?  Re-arrangements are not fun to study……….
           -Zack