Acetylacetone (pentane-2,4-dione) reacts with sodium hydroxide to...

Question

Acetylacetone (pentane-2,4-dione) reacts with sodium hydroxide to give water and the sodium salt of a carbanion. Write a complete structural formula for the carbanion, and use resonance forms to show the stabilization of the carbanion. acetylacetone (pentane-2,4-dione)

Accepted Answer

Hey everyone, let's solve this problem. It says predict the structure of the an I informed by the abstraction of a proton from the following compound. Using N A. O. H. Also draw the important resonance forms involved in the stabilization of this an ion. And our compound we have is metal aceto acetate. So we have a decent amount of hydrogen is here. We have a method group on each side of the compound and this carbon in the middle has two hydrogen. So where do we think our O. H. Is going to be protein eight. This compound? Well this carbon is an alpha carbon so it is going to deprive innate hydrogen from that carbon. Okay, because the alpha hydrogen on the alpha carbon is the most acidic will create the most acidic structure. Okay, or be the most should be the most acidic structure rather. So let's see what resonance forms are involved when we deep resonate that hydrogen. So remember the electrons will go from this hydrogen onto that carbon. Right. And we will have so this carbon will have a hydrogen and now a lone pair which gives it a negative charge. Okay. Any other resonance forms we can have here? Yeah, I see a negative charge next to two pi bonds. So there will be some resonance here. Well, we can sort of go either way, right. If the negative or the electrons go in between these two carbons, the electrons from that double bond will go up onto the oxygen giving us something like this. So now that oxygen has a negative charge. And similarly if those electrons swing down and go the other way, we will have sort of the mirror of that structure, with the left oxygen having that negative charge and our double bond Being between those two carbons instead. So those are our resonance structures. So since there are three residents forms, this compound is pretty stable in this an ion form. Why did I? D pro donate this hydrogen rather than Yes, this hydrogen rather than the hydrogen is off of this carbon because this carbon is technically also alpha two, that carbondale group. Well, let's see what it would look like if I were to do that. So, if I were to d protein ate one of those hydrogen is now my negative charge would be over here and I could still have a resonance form right. The electrons will swing down from that carbon and they will move from that double bond onto the oxygen. So now we would have a double bond, Our oxygen has a negative charge. But that is the only resonance form I could have. Okay, there's only these two resonance forms. So since this first deep throat nation, that middle carbon has three residents forms, that's going to be the most stable, which means it will be the most acidic. Okay, so this one is less likely to occur. Okay, so these are the resonance structures for the most stable an ion the most acidic form of this compound. I hope this video is helpful and thanks for watching.

Acetylacetone (pentane-2,4-dione) reacts with sodium hydroxide to give water and the sodium salt of a carbanion. Write a complete structural formula for the carbanion, and use resonance forms to show the stabilization of the carbanion. acetylacetone (pentane-2,4-dione)

Watch next