[Altered State]

In this problem I need to propose a good method to do these transformations:



I know there are some different ways, but I have to do it using sulphur chemistry.

For the first one, I thought of a alpha-halogenation, and then, Swern reaction (DMSO, heat) to give 1,2-diketone
Then use Julia olephination to give the alkene. I guess I'll need to protect one of the carbonyl (after alpha-halogenation and before Swern oxidation).
But I see this method kind of "overcomplicated", any other idea?

For the last one I'm gonna need some hints, because I see the possibility of epoxide opening and then elimination. But that does not involve sulphur compounds chemistry, which I need to use.

Thanks in advance

[mst]

My idea for 1 would be Julia olefination, riley oxidation, swern oxidation.

For two the best thing i came up with is Ring opening with hydroxy, mono tosylation followed by elimination.

[ziqquratu]

For the first one, check out the reaction of trimethylsulfoxonium iodide with cyclic ketones in the presence of a strong base (KOtBu, I think). It's related to the Corey-Chaykovsky reaction, but rather than giving the epoxide, you can get the a,b-unsaturated ketone you describe. It's one step from the ketone, and I know that that EXACT reaction is in the literature because we had an undergrad student running it last year!

If you have access to SciFinder, search for that reaction; otherwise Google should find it for you.

[Altered State]

For the first one, check out the reaction of trimethylsulfoxonium iodide with cyclic ketones in the presence of a strong base (KOtBu, I think). It's related to the Corey-Chaykovsky reaction, but rather than giving the epoxide, you can get the a,b-unsaturated ketone you describe. It's one step from the ketone, and I know that that EXACT reaction is in the literature because we had an undergrad student running it last year!

If you have access to SciFinder, search for that reaction; otherwise Google should find it for you.

I serached that reaction and I see how this reaction works, but I don't see how can it yield a,b-keto-alkene and not the epoxide...

[orgopete]

If you want to use sulfur, why not use the sulfoxide elimination reaction in as used in the "annelation and elimination" question you posted?

[Altered State]

If you want to use sulfur, why not use the sulfoxide elimination reaction in as used in the "annelation and elimination" question you posted?

How would you add CH₂S(O)Ph group?
Just make enloate of ketone and then add Br-CH₂-S(O)-Ph?

Or better add Br-CH₂-S-Ph and then oxidize with NaIO₄/MeOH

And then heating would give the product of beta elimination

[orgopete]

I'd choose the "Or better…" route. You should be able to do the allylic alcohol the same strategy, sulfide, sulfoxide, and elimination.