for those interested, in the second step with NaBH4, the C attached to HgOAc has a partial positive charge. NABH4 dissociates in water to form Na+ and H-BH3. Electrons from the H bond of H-BH3 attack the C with the positive charge, attaching H- (hydride ion) and removing the remaining HgOAc as a leaving group.
If I ever make any good money from all this studying, I promise to get you some as a token of my appreciation. I have watched your videos for so many classes and I believe they have had a significant impact on how successful I have been at them. Sincerely, thank you!
College professors make chemistry seems too hard, you make it I am sweet. I am sure they can watch your videos before they start teaching their nonsense.
What happens if a new chiral center is formed, how is the stereochemistry determined? For example if there was another methyl group on the adjacent carbon in your cyclohexane example at 6:32?
Question - during 9:50 , I used CH3OH as a weak base due to the strong electronegativity of oxygen (kinda how H2O behaves ), would that still be correct? thnx... great video bro, I've been grunting out practice sessions before my exam, these videos really helped.
My professor only referenced the charges. If he wouldve talked about the stability of the transition states to decide where water will attack to open the mercuric ring, it would've been much easier
Last example its symmetrical thus achiral carbon.Dont you think chiral carbon are to be achieved to show the enantiomer of the compound formed??? Just asking
Sir why isn’t water anti to HgOaAc ? We saw it in Bromine water case that it attacks due to the crowding so isn’t this providing enough steric hindrance for Anti addition?
I think I knwo the awnser to why NaBH4 reacties with the HGOAc group. NaBH4 donates a negatif H (H with 2 elektrons) that will atack the C-Hg bond. HgOAc wil come of and the H- is added to the molecule. at least that is what my chemistry book of university says. Greatings from Belgium and sorry for the bad englisch
Even if u don’t write the sodium nabh4 u still replace the Hoac to a H. Cuz I thought the answer would b what u had but just not switch the mercury acetate to an H
If the Hg-OAc was bonded to the more substituted carbon it would have a harder time bonding with other butene molecules so its more favorable for Hg-OAc to be on the less substituted carbon where its less shielded by other atoms and more free to form other bonds. Anti-markovnikov is the result of electrophilic centers being able to have more than 1 bond. The reason water attacks the 2 substituted carbon is because Hg-OAc is less stable when bonded to that carbon meaning the partial positive charge on the 2 substituted carbon is greater and the -OH will have a greater attraction to that carbon than Hg-OAc's carbon.
it is an ionic exchange i think.....mercury is a metal hence electropositive so it can easily lose those 2 6s2 electrons and form two bonds with the oxyacetyl groups that each have uni negative charge. the medium of the reaction (usually aqueous) makes it easy to break the ionic bonds due to the ion dipole interactions of mercury and the two OAc groups...................i could be wrong but that is what i understood.
why dont you include the stereochemistry in these problems? Essentially they are useless if you are giving the watered down version. I want to see more with stereochemistry!
Because there is no carbocation formed. Only a positive partial charge has developed. Rearrangements happen with carbocation and free radicals not partial charges.
These videos are great, however I wish he used condensed structure as well as line structure. Line structure can be a little confusing when explaining reactions.
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for those interested, in the second step with NaBH4, the C attached to HgOAc has a partial positive charge. NABH4 dissociates in water to form Na+ and H-BH3. Electrons from the H bond of H-BH3 attack the C with the positive charge, attaching H- (hydride ion) and removing the remaining HgOAc as a leaving group.
why does the HgOAc give the C a partial positive charge
If I ever make any good money from all this studying, I promise to get you some as a token of my appreciation. I have watched your videos for so many classes and I believe they have had a significant impact on how successful I have been at them. Sincerely, thank you!
wow, thank you, I was trying to figure out the mechanism by myself without success, thanks a lot!!
You're welcome.
every video I have seen of yours helps me understand orgo so much better!!! thank you sm!
Thank you for making this video! I could easily understand the mechanism with your clear explanation .
College professors make chemistry seems too hard, you make it I am sweet. I am sure they can watch your videos before they start teaching their nonsense.
Par par Sharif we study this in 11th std.
Aryan ; yes
You're a lifesaver!
What happens if a new chiral center is formed, how is the stereochemistry determined? For example if there was another methyl group on the adjacent carbon in your cyclohexane example at 6:32?
Question - during 9:50 , I used CH3OH as a weak base due to the strong electronegativity of oxygen (kinda how H2O behaves ), would that still be correct? thnx... great video bro, I've been grunting out practice sessions before my exam, these videos really helped.
I dont even need to go college lectures anymore! Thank you
It helps me to understand the reaction.
Thank you
ur very good at teaching. thank u
This video helped so much, thank you!! XD
7:13, why doesnt the molecule rearrange at the stage from the 2 deg to 3 deg carbon??
is this example the only exception ??? or ??
Great work, thanks alot 😍
My professor only referenced the charges. If he wouldve talked about the stability of the transition states to decide where water will attack to open the mercuric ring, it would've been much easier
does this process not have any sterochemical concerns? for the OH its a chiral center?
Last example its symmetrical thus achiral carbon.Dont you think chiral carbon are to be achieved to show the enantiomer of the compound formed??? Just asking
Sir why isn’t water anti to HgOaAc ? We saw it in Bromine water case that it attacks due to the crowding so isn’t this providing enough steric hindrance for Anti addition?
at 7:30, why is there no hydrogen attached to the primary carbon?
There is . He just didn’t show it. You see that’s why last part becomes Ch3 otherwise it would have remained Ch2. That H is added and made it Ch3.
Awesome video
I think I knwo the awnser to why NaBH4 reacties with the HGOAc group. NaBH4 donates a negatif H (H with 2 elektrons) that will atack the C-Hg bond. HgOAc wil come of and the H- is added to the molecule. at least that is what my chemistry book of university says. Greatings from Belgium and sorry for the bad englisch
Saved my life !
can you please go over the demercuration mechanism with NaBH4 please
You are awesome sir
Thank you sir
Even if u don’t write the sodium nabh4 u still replace the Hoac to a H. Cuz I thought the answer would b what u had but just not switch the mercury acetate to an H
Sir, so if we use an alkyne, 2 OH groups come on the same carbon, and it loses water to give a ketone?
Why is water attacking at the 2° position
If the Hg-OAc was bonded to the more substituted carbon it would have a harder time bonding with other butene molecules so its more favorable for Hg-OAc to be on the less substituted carbon where its less shielded by other atoms and more free to form other bonds. Anti-markovnikov is the result of electrophilic centers being able to have more than 1 bond. The reason water attacks the 2 substituted carbon is because Hg-OAc is less stable when bonded to that carbon meaning the partial positive charge on the 2 substituted carbon is greater and the -OH will have a greater attraction to that carbon than Hg-OAc's carbon.
how the mercury bonds with two oxyacetyl group its outer configuration is 6s^2 how the bonding happens?
it is an ionic exchange i think.....mercury is a metal hence electropositive so it can easily lose those 2 6s2 electrons and form two bonds with the oxyacetyl groups that each have uni negative charge. the medium of the reaction (usually aqueous) makes it easy to break the ionic bonds due to the ion dipole interactions of mercury and the two OAc groups...................i could be wrong but that is what i understood.
why dont you include the stereochemistry in these problems? Essentially they are useless if you are giving the watered down version. I want to see more with stereochemistry!
How does omdm reaction form an anti addition product
can you explain why there is no carbocation rearrangement
Because the reaction is so fast that only transition state is formed and no carbocation
in the second example isn't there a possibility for shifting of the positive charge to the 3degree carbon???
No rearrangements in this reaction....
Because there is no carbocation formed. Only a positive partial charge has developed. Rearrangements happen with carbocation and free radicals not partial charges.
why doesn't rearrangement take place in oxymercutation demercuration reaction??????.
because there is no carbocation formed
Hg(OAc)2 has a lone pair on mercury atom?!
Thanks a lot!
If carbocation is formed won’t it shift to tertiary carbon in the second question?
Carbocations is not formed. Only a partial charge has developed.
I just wonder why Hg(OAc) has 1 lone pair.. Can you explain to me.. Thanks a lot
Oxygen has 3 bond, whenever oxygen has 3 bonds it has 1 lone pair, and a positive charge.
Tq so much
Thanks
Thanks 😏
Shortcut for the people in the comments, just follow Markovnikov's rule but do not perform rearrangements
These videos are great, however I wish he used condensed structure as well as line structure. Line structure can be a little confusing when explaining reactions.
Too many Asians here
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Thanks alot!