Aldol condensation | Alpha Carbon Chemistry | Organic chemistry | Khan Academy

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Khan Academy Organic Chemistry

Khan Academy Organic Chemistry

Күн бұрын

Пікірлер: 33
@j.a.7047
@j.a.7047 6 жыл бұрын
Hey everyone, just to clarify, -OH is a good leaving group in this situation. It does not get converted to H2O.
@visheshjain1999
@visheshjain1999 8 жыл бұрын
-OH is not a good leaving group,thats why we make it -OH2+ and then make it leave,but at 6:10 ,you made -OH leave,how?
@Yashpandey467
@Yashpandey467 8 жыл бұрын
Vishesh Jain because it's already a highly basic medium and so (oh-) becomes a strong leaving group
@katp9116
@katp9116 8 жыл бұрын
Can you actually explain this a little further, or lets say, dumb this down a little?
@TheAttacker96
@TheAttacker96 7 жыл бұрын
the reason the -oh is able to leave even though it is a bad LG is because having the molecule become conjugated is a lot more stable. the stability from having a conjugated molecule allows the oh to leave
@tunneltrance
@tunneltrance 6 жыл бұрын
its base catalyzed so it has to reform at the end somehow
@shinn-tyanwu4155
@shinn-tyanwu4155 6 ай бұрын
Very informative 😊
@grant4360
@grant4360 2 жыл бұрын
Where does the initial OH- come from if it is introduced in solution as NaOH, then how does it break apart and retain its charge?
@DonotWorryIAmHere
@DonotWorryIAmHere 8 жыл бұрын
Only constructive criticism: He should've shown the protonation of the -OH group before it left! ( -OH "hydroxide" is a TERRIBLE LEAVING GROUP) other than that, thanks for the brilliant clarification! -cheers!
@hansenyang4014
@hansenyang4014 Жыл бұрын
No that is incorrect. This reaction is done in basic conditions so the OH group cannot be protonated. The reaction is done in NaOH so the OH group can leave without much difficulty and reinforce the alkaline nature of the solution. I know this comment was made six years ago but I hope this clarifies the same question for future viewers.
@renilkumarak6406
@renilkumarak6406 9 жыл бұрын
Thanks :')
@zahrashahabinezhad
@zahrashahabinezhad 4 жыл бұрын
Why can't OH be removed from the aldol before the deprotonation?
@bonbonpony
@bonbonpony 2 жыл бұрын
Because -OH groups are not good leaving groups normally. (Otherwise, alcohols would be rather unstable :q ) The bond between the oxygen and carbon is pretty strong. Protonation makes it a better leaving group because it gives the oxygen more positive charge, and it doesn't pull the electrons so strong towards itself anymore. They are pushed away more closer to the carbon, and if you give them a little more nudge, they can go there and stay there, breaking the bond between the carbon and the oxygen.
@katp9116
@katp9116 8 жыл бұрын
Hey, So does the -OH group get protonated before it leaves or no? Some people (in the comments) are saying yes and some are saying no. If it doesn't, can you explain why not?
@hansenyang4014
@hansenyang4014 Жыл бұрын
No that is incorrect. This reaction is done in basic conditions so the OH group cannot be protonated. The reaction is done in NaOH so the OH group can leave without much difficulty and reinforce the alkaline nature of the solution. I know this comment was made six years ago but I hope this clarifies the same question for future viewers.
@zarazainab9871
@zarazainab9871 3 жыл бұрын
THANKYOU SIRRRR
@kamh
@kamh 5 жыл бұрын
The reason why the OH group can leave is because the reaction proceeds via an E1CB where CB means conjugate base. The protons on the alpha carbons ie the ones that are adjacent to the carbonyl are relatively acidic and so can be deprotonated by a weak base. This results in the enolate anion to form which is a relatively stable conjugate base. although this anion is stable it still prefers to lose an OH group ( Due thermodynamic stability reasons) and so the oxygen on the enolate ion collapses back which kicks of the adjacent double bond which then subsequently kicks off the OH group. Hope this helps.
@bonbonpony
@bonbonpony 2 жыл бұрын
What does the heat change in this picture so that the reaction can proceed further than without it?
@ghadeer5049
@ghadeer5049 8 жыл бұрын
gorgeous 😍 Thank you 🌸
@saumyatrivedi373
@saumyatrivedi373 8 жыл бұрын
video is really awesome. thanks man!
@kristinaf.2648
@kristinaf.2648 2 жыл бұрын
Could somebody verify, (English is my third language) the aldol consendation is always as a two step mechanism to view at? First step, aldol addition then the actual consendation?
@bonbonpony
@bonbonpony 2 жыл бұрын
Yes, the condensation is like an extra step. The reaction is allowed to go further when there's more heat.
@asheearif8990
@asheearif8990 7 жыл бұрын
Uhhh gooosshhhh what the hellll... m still in this confusion what is the difference b/w aldol reaction and aldol condensation
@jcmick8430
@jcmick8430 2 жыл бұрын
Reaction refers to the enolate condensation when we form pi bond
@martinofgliwice1486
@martinofgliwice1486 9 жыл бұрын
May I synthesise 2,6-dimethylhex-2-enone from 5-oxo-4-methylheptanal via intramolecular aldol condensation?
@kevinsolomon6742
@kevinsolomon6742 5 жыл бұрын
Lightning fast.
@thelabadabada
@thelabadabada 8 жыл бұрын
Why is it called a condensation reaction ? whe is the elimination of water ?
@fionaWhatever
@fionaWhatever 7 жыл бұрын
thelabadabada Well you have a OH- leaving group plus the Proton taken by the base, so technically H2O is eliminated
@aslinvazqueznieves2986
@aslinvazqueznieves2986 6 жыл бұрын
Because what leaves is H, not water. When we eliminate water from a molecule, the OH is first protonated and then leaves in the form of water. Here, an eternal OH molecule captures de H, so the thing leaving the molecule is an H, but when the Leaving H combines with the molecule that took it (OH) it produces water
@dr.abeyweera6819
@dr.abeyweera6819 6 жыл бұрын
Can you explain the conversion of 1 octen 3 one to 1 octen 3 ol
@MyDragon98
@MyDragon98 2 жыл бұрын
city off ba
@helihel1323
@helihel1323 6 жыл бұрын
Why you explain so fast just ?!!!!!
@041-garimasaraswat5
@041-garimasaraswat5 4 жыл бұрын
Garima saraswat roll no 41 secA
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