[Mark S 2014]

Hi,

I'm just looking through some previous exam papers. For this particular section, the focus has been on enols/enolates and some aldol reactions. I really can't figure out the reagents for this reaction, it looks really out of place with the other questions which are simple aldol reactions and halogenation of enols.

It says provide curly arrow mechanisms here. The only route I could think of was to reduce the ketone to an alkane with Zn/Hg and HCl, then maybe oxidise the alkane to a carboxylic acid using KMnO4. This wasn't covered at all in this section, and I've never met a mechanism for it so I'm pretty certain this is wrong. It must have something to do with enolisation some how, but I cannot see how.

If anyone can put me in the right direction, it would be much appreciated, thanks.

(The question is attached as a jpg)

[Mark S 2014]

Ah I think I have it now, it would be a halogenation in base. I was thinking too hard about that one, if I just use NaOH with Br₂, then the haloform should leave and I should be left with the carboxylic acid. Should have seen this earlier ! Thanks anyway !