[BeepoGirl]

Ok, I want to know how the reduction of enones (alpha beta unsaturated ketones) works with what I assume is dissolving metal reduction.

enone + Li / NH_{3 (l)}   ketone

but I can't work out how it works mechanistically. Can anyone help?

[stewie griffin]

I unfortunately don't have chemdraw on the computer I'm at. However I can give you some clues and hopefully can piece together a reasonable mechanism.
Li/NH₃ give you a solvated electron. So you're going to be doing some radical chemistry. Pump the electron into the double bond of the carbonyl to get and O minus and a C radical. Then draw a new resonance structure where you now have an enolate and a different C radical (this carbon should be the carbon of the alkene that's farthest away from the carbonyl). Now pump a second electron onto this new C radical to give you a C anion. So now you have an enolate and a carbon anion. When you add a proton source (water, methanol, NH₄Cl, etc) to quench the reaction the carbon anion grabs the proton and the enolate gets protonated as well.
If you draw the enolate as becoming the enol, that's fine.. just tautomerize back to the ketone. Otherwise draw the enolate as attacking the proton at the alpha carbon.