Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: rekhasharma on June 08, 2010, 05:49:02 PM

Title: Mechanism of sicl4 reaction
Post by: rekhasharma on June 08, 2010, 05:49:02 PM
Can somebody help with mechanism of attached reaction?
Title: Re: Mechanism of sicl4 reaction
Post by: bromidewind on June 09, 2010, 02:54:20 AM
I can't draw out a mechanism right now, so I'll give you some hints as to what's going on here instead.

SiCl4 is a weak Lewis acid, right? So what happens when you react a ketone with a Lewis acid? The product of this reaction, which reacts with itself, will help you see how the final compound comes together. Don't forget about that bromine on the benzene as well. It's an ortho/para-director, but deactivating.

Hope this helps! If you give this a shot and are still lost, I'll try to draw up a mechanism for you.
Title: Re: Mechanism of sicl4 reaction
Post by: rekhasharma on June 09, 2010, 05:19:32 PM
I tried but totally lost... couldnt reach the product.... Please help
Title: Re: Mechanism of sicl4 reaction
Post by: rekhasharma on June 10, 2010, 01:33:24 PM
PLease Help with this mechanism...
Title: Re: Mechanism of sicl4 reaction
Post by: Doc Oc on June 10, 2010, 02:35:55 PM
I tried to work this out for a while and finally caved in and looked it up.  There's a decent explanation given in this paper:

J. Org. Chem.  1992, 57, 1627.

Basically just a series of aldol reactions, which is what I guessed, but I couldn't figure out how to get around the last methyl group just hanging off from the first aldol.
Title: Re: Mechanism of sicl4 reaction
Post by: maxyoung on June 10, 2010, 02:59:13 PM
Quote from: J-bone on June 10, 2010, 02:35:55 PM
I tried to work this out for a while and finally caved in and looked it up.  There's a decent explanation given in this paper:

J. Org. Chem.  1992, 57, 1627.

Basically just a series of aldol reactions, which is what I guessed, but I couldn't figure out how to get around the last methyl group just hanging off from the first aldol.

I guess the ketone enol tautormerization could help. The enol form is a triene, which could cyclize via a pericyclic mechanism.