[cseil]

Hello,
I would like to know if my procedure is correct. I don't think that an aldolic addition could happen.
If it's wrong can you give me a hint?

[cseil]

I ask this procedure because I'm trying to do a synthesis and the only method I can find to do it is to apply the reaction I showed before.
The book asks me to obtain the final product using only 5 carbon atoms reactants.

[pgk]

According your opinion, what is more stable, a bromide anion as leaving group or a formation of an enol anion?
However, the second reaction example is more complicated because you have a carbanion formation via a conjugated aldol reaction which is competition with a non conjugated one, together with the intramolecular SN2. Please, draw the reaction mechanism, in detail, in order to clarify this.
Which one would be  more favorable, a conjugated or a non-conjugated aldol reaction and why?

[cseil]

The bromide anion as leaving group is more stable.
Enolates are soft nucleophiles, so they'll do the conjugate addition.

I drew the mechanism of the conjugated addition + intramolecular sn2. Should I write the non conjugated addition mechanism?

[orgopete]

The bromide anion as leaving group is more stable.
Enolates are soft nucleophiles, so they'll do the conjugate addition.

I drew the mechanism of the conjugated addition + intramolecular sn2. Should I write the non conjugated addition mechanism?

The conjugate addition has little chance of success. Although it has been written to indicate a "hoped for" product, the chemicals may not abide with this wish. For example, what would prevent an aldol cyclization to give a cyclopentenone or elimination of the bromide beta to the ketone? Those eliminations are generally very facile.

If you look at examples of conjugate additions in your textbook, I'm assuming you will not find many examples of methyl ketones. I think they are more likely to give 1,2-addition than 1,4. I recently commented on my opinion regarding a simple rule to suggest which route would prevail.

[pgk]

orgopete is right.
Comparing reactions mechanisms helps to have just an idea which reaction would be more or less favorable.