[John Mcmurry]

Hello!

Could anybody help me out finding the reagents for a succesful synthesis starting with cyclopent-4-ene-1,3-dione and ending with spiro[4.4]non-2-ene? I am totally lost on that one.

Thanks...

[clarkstill]

It is a forum rule that you must at least show that you've attempted the problem.

Have you had any instruction on retrosynthesis?

[John Mcmurry]

Nope...

[Babcock_Hall]

Basically, it involves working backward from the product one step at a time.  Let's see what you can come up with...

[rolnor]

The dione has very acidic hydrogens and would form a good nucleophile if base were added but it is also a excellent Michael-type alpha-beta unsaturated molecule and would probably polymerase very quickly under basic conditions, its a tricky startingmaterial.

[clarkstill]

I would start by numbering atoms in the starting material and products, to identify where you need to make and break bonds.

[John Mcmurry]

I can't find any mechanism that makes sense in this case

[John Mcmurry]

I can't even find a way to remove the two C=O bonds. Maybe reduce them to C-OH, but what then?

[John Mcmurry]

Reducing the C=O by grignard to C-OH

[wildfyr]

There are many ways of reducing a ketone to an alkane. In fact if you type "ketone to alkane" into google the easiest way is the first result.

However, I suggest that this reduction not be your first step. You have a highly activated spot between the two carbonyls, what type of chemistry could you do there?

[John Mcmurry]

Wolff-Kishner Reduction, my bad!

Between the two carbonyls, maybe NBS and hr, inserting an Br. Then making an diorganocopper reaction with my R'-Br and the cyclopentane-CuLi?

[John Mcmurry]

Then I got this? Can I then reduce the two C=O with W-K reduction? and the synthesis is done

[John Mcmurry]

Something like this?

[wildfyr]

Very good, and very close. Take a look again at your cuprate. Its a bit off.

[John Mcmurry]

But I just realized that I would end with this, right?