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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: DannyBoi on February 25, 2011, 05:09:03 PM

Title: Reaction Mechanisms with Aluminum.
Post by: DannyBoi on February 25, 2011, 05:09:03 PM

Hi,

I am trying to answer the reaction mechanisms for these reactants but I haven't seen them before in class. Are there clues which might help me out in solving the problems? I only see lone pair electrons on the oxygen in the first question and also the fluorines because I think Al can be neutral without fulfilling the octet rule, just like Boron. Would the oxygen attack the Al or is it completely different mechanism? Thanks :)(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg718.imageshack.us%2Fimg718%2F4475%2F83067468.png&hash=49bdd4c727af989d172f308547402eaa9d7eef8c)

Title: Re: Reaction Mechanisms with Aluminum.
Post by: MissPhosgene on February 25, 2011, 05:33:38 PM

You seem to be on the right track.

For the first one, you form an AlF3 * OMe2 complex.

For the second one, what's the base and what is the acid?

Title: Re: Reaction Mechanisms with Aluminum.
Post by: DannyBoi on February 25, 2011, 07:08:23 PM

Hi MissPhosgene!

So for the first one I had originally drawn an awkward looking product but this is what I have as the answer:
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg195.imageshack.us%2Fimg195%2F7093%2F44587195.jpg&hash=58cef7d6b5142fe737c5c7be6b8273d24d05be91)

Is this the best and correct way to draw it? :)

Title: Re: Reaction Mechanisms with Aluminum.
Post by: contra on February 25, 2011, 07:15:54 PM

If it's the correct product (which I'm unsure of), the oxygen should be labeled as positive*. Since it has three bonds to it.

Title: Re: Reaction Mechanisms with Aluminum.
Post by: DannyBoi on February 25, 2011, 07:38:01 PM

Yes you're right, I have revised it. Thanks

This would be my second answer:

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg834.imageshack.us%2Fimg834%2F874%2F58023567.jpg&hash=2954cafed45139f42853e980db52480d5c041dc6)

Title: Re: Reaction Mechanisms with Aluminum.
Post by: MissPhosgene on February 25, 2011, 08:48:25 PM

Hello

  Looks good!

People usually represent lewis acid complexes as (using your example): AlF3 dot OMe2. Can't do it right because I don't know how to make a dot.

Title: Re: Reaction Mechanisms with Aluminum.
Post by: DannyBoi on February 25, 2011, 09:04:15 PM

Oh I think I've seen such a thing! Thanks :)

Title: Re: Reaction Mechanisms with Aluminum.
Post by: orgopete on February 27, 2011, 11:28:28 PM

The aluminum should have a negative charge on it also. Two neutrals should yield a net neutral charge.