ochem from destroyer

[Bis-GMA111]

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number 13 from the 09 edition of destroyer orgo..

has a cyclic ketone reacting with Cl2 excess in H3O+

why would all of the alpha carbons be chlorinated since the conditions are acidic? wouldn't all alpha carbons be chlorinated only under basic conditions?

 

[orgohacks]

number 13 from the 09 edition of destroyer orgo..

has a cyclic ketone reacting with Cl2 excess in H3O+

why would all of the alpha carbons be chlorinated since the conditions are acidic? wouldn't all alpha carbons be chlorinated only under basic conditions?

You can also chlorinate alpha carbons under acidic conditions. The key thing here is that the acid is helping the ketone make the enol, and it is the enol that reacts with Cl2 to form the chlorinated carbon.

Just like it's shown here: http://masterorganicchemistry.com/2010/05/05/another-awesome-example-of-acid-catalysis/

hope this helps - James

 

[Clancyp]

number 13 from the 09 edition of destroyer orgo..

has a cyclic ketone reacting with Cl2 excess in H3O+

why would all of the alpha carbons be chlorinated since the conditions are acidic? wouldn't all alpha carbons be chlorinated only under basic conditions?

I had the same question. Especially since Chad's videos do it with Br in acid and it only adds to one alpha opposed to when in base it adds to both alphas, twice.


EDIT: I was just going over Road Map 5, and Im confused again about this somewhat... the arrow below start goes to a ketone then the arrow left from that ketone reacts it with Cl2(XS) in OH-, which doesnt that also apply to this? Yet it ends up breaking the ketone into a carboxylic acid and methyl chloride