Aldol Condensation Help Plz

[DJtiesto]

---

Members do not see this ad.

I am getting so damn confused as to what the final product is in this reaction.

These are the two products I am getting mixed up:

1) Beta-Hydroxy: After the enolate attacks the carbonyl, the oxygen (that was attached to the carbon being attacked) gets protonated to form the B-hydroxy.

2) Alpha-Beta Unsaturated Ketone/Aldehyde: Same steps from (1) but now the molecule undergoes elimination.

So...is one product favored over the other in certain situations? I.e. how do I know if the product from (1) will stay or undergo elimination? I have seen it both ways.

Thanks

 

[Phosphorus Ylide]

I am getting so damn confused as to what the final product is in this reaction.

These are the two products I am getting mixed up:

1) Beta-Hydroxy: After the enolate attacks the carbonyl, the oxygen (that was attached to the carbon being attacked) gets protonated to form the B-hydroxy.

2) Alpha-Beta Unsaturated Ketone/Aldehyde: Same steps from (1) but now the molecule undergoes elimination.

So...is one product favored over the other in certain situations? I.e. how do I know if the product from (1) will stay or undergo elimination? I have seen it both ways.

Thanks

If you use mild conditions, you will get the product 1 (ie room temp and stoichiometric equivalent amount of acid/base). If you use excess acid/base or high temps, it will react to completion yielding product 2. Very similar, but slightly different mechanisms between acid and base catalyzed.

 

[DJtiesto]

.