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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: zhengiskhan on April 26, 2016, 12:14:57 PM

Title: Amine and alcohol transformed into ketones.
Post by: zhengiskhan on April 26, 2016, 12:14:57 PM

Hi,

I was reading a synthesis of Morphine and I don't understand the following step involving ferric chloride and hydrogen chloride. What happened to the amine and alcohol ? I don't see how both of them became ketones

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Flm3OxYS.jpg&hash=db2f62d7bc13ae30bbd02b982e09e0a097e62941)

Thank you

Title: Re: Amine and alcohol transformed into ketones.
Post by: Babcock_Hall on April 26, 2016, 03:27:07 PM

I would assign oxidation numbers to the carbon atoms in the reactant and product.  This can be done for each carbon atom by subtracting the number of bonds to hydrogen from the number of bonds to oxygen, nitrogen, or halogen atoms.

Title: Re: Amine and alcohol transformed into ketones.
Post by: Unco on April 27, 2016, 12:55:52 AM

I can take a shot at the mechanism; ferric chloride acts as a lewis acid, and bind to the lone pair on nitrogen and thus activating it, next the lone pair on oxygen pushes down to the carbon it's connected to, and the pi bond on the alkene proceeds to move to the activated nitrogen and the ferric chloride then leaves the nitrogen with its lone pairs. Now you end up with an iminium (previously the primary amine), and a ketone (previously an alcohol), the next steps is just hydrolysis of the iminium (like a reverse of iminolysis) which would ultimately convert the iminium ion into the ketone (byproduct is ammonia). And voila you end up with the 1,2 diketone

Title: Re: Amine and alcohol transformed into ketones.
Post by: Babcock_Hall on April 27, 2016, 08:56:23 AM

@OP,

According to the Forum Rules, you must show an attempt or your thoughts before we can help you.