Just noticed this was new. I have watched almost all of your orgo videos and find the approach very helpful. Not too slow, but generous with explanations. Nice work!
I never thought about the four-membered ring transition state in terms of electronegativity, but that makes perfect sense! Thanks again for sharing all of these wonderful explanations. You are doing ochem students everywhere a great service!
Wow... I just wanna say thank you. I never thought I would be able to understand the concepts in organic chemistry but for the very first time, I did. You don't even understand the huge difference that you just made. Thank you sooooo much 😭❤️
thanks man! you're videos are helping students even all the way to Germany! Love your way of calmly explaining and giving multiple illustrations. Cheers!
Yes, alkyl halides are used to attach the alkyl group to Pph3 in presence of BuLi. The mechanism is as follows: You have Pph3 and RX with BuLi. The alkyl halide has polarity between it's bond and the phosphorus in Pph3 has lone pair which gets attracted with the partial positive polarity of alkyl in alkyl halide Pph3 + RX ---> (ph3)-P(+)-R The Phosphorus has made a bond with alkyl and it has positive charge in it. Now comes BuLi which deprotonates the alkyl and make a complex with Li. (ph3)-P(+)-R + BuLi -----> [(ph3)-P(+)-R(-)]Li The alkyl now has a negative charge. Remember the the positive and negative don't make any pie bond due to presence of Li. Now it is ready to attack alkyl ketone. This is what I learnt in my class. Hope you might find something new in it. It's hard to write structure here, you can draw them accordingly to understand better. Hope it helped!
I think the phosphorus atom has five bonds, counting the sigma and pi bonds to the carbon atom separately. So the formal charge is #valence electrons - #bonds - 2*#lone pairs = 5 - 5 - 0 = 0.
Hello, at 10:00, when forming the cyclo compound, when do I know the electrons are transferred from 1 bond to another bond or from 1 bond to an atom e.g. Oxygen / Carbon? Is there ant general concept I should be known about? Thanks
Tony Lee There are many different scenarios which control this, no single rule really, here though in your question, the two carbons are attracted because of their opposing electronegativoty and positivity. You also need to know carbon never has 5 bonds, so when this 5th bond is made, it must drop another to go back to 4, it chooses to break one of the bonds on oxygen because it tries to break a bond without loosing any atoms if possible, so if it broke any other bonds atoms would leave. Know this oxygen withdraws the electrons after the bond breakage, as it is more electronegative than carbon. This negative oxygen readily combines with the positive pph3, forming that structure.
I strongly Recommend you to see 👇👇 ua-cam.com/video/tJHmnWxPMVE/v-deo.html For witting reaction: 16:00 🖕🖕 Do see the lecture that I shared with you...You all will for sure understand much much better.. #PROUD TO BE INDIAN 🇮🇳💗💯
It’s not correct!!! Yes you get a mixture but in the example of using a alkyl-Ylide you will get >= 90% Z alkene because it’s a labile Ylide. 50/50 would be only if you use a Aromatic ring or system as the funktional group of the Ylide. For E alkene you have to use very stable Ylides with EWG funktional groups on the Ylide!!!! 10:59
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Just noticed this was new. I have watched almost all of your orgo videos and find the approach very helpful. Not too slow, but generous with explanations. Nice work!
I never thought about the four-membered ring transition state in terms of electronegativity, but that makes perfect sense! Thanks again for sharing all of these wonderful explanations. You are doing ochem students everywhere a great service!
perfect timing
organic chem 2 final next week :(
How did it go?
Yeah, how did the test go?
yep I passed and I graduated 💃🏻
stay strong 💪🏻
@@ahlam9276 That is really awesome to hear; way to go! I also think it's cool to hear from you after leaving your comment three years ago.
Wow it was so long ago
Major update
I teach organic chemistry now 😂 did not see that coming
You explained it so well that I could hug you
Wow... I just wanna say thank you. I never thought I would be able to understand the concepts in organic chemistry but for the very first time, I did. You don't even understand the huge difference that you just made. Thank you sooooo much 😭❤️
thanks man! you're videos are helping students even all the way to Germany! Love your way of calmly explaining and giving multiple illustrations. Cheers!
The Wittig is Z-selective. The Horner-Wadsworth-Emmons and other stabilized ylids with similar mechanisms give E-stereochemistry.
You really make these explanations easy ... i appreciate you
I wish my professor explained concepts this well. Thank you so much😭
Thanks a lot. I love your videos and use it for my revision!!
this was very helpful
didn't understand at first but now I do
Thanks a lot
U made it so easy to understand 😱
This is a total life saver
you helped a pharmacy student from turkey😊
Very helpful for students like us who can't ask their teachers due to our absentee
Question: What compounds are used to go from ph3P to ph3P=R? If they're alkyl halides then why do compounds with Li work? Please explain.
Yes, alkyl halides are used to attach the alkyl group to Pph3 in presence of BuLi. The mechanism is as follows:
You have Pph3 and RX with BuLi.
The alkyl halide has polarity between it's bond and the phosphorus in Pph3 has lone pair which gets attracted with the partial positive polarity of alkyl in alkyl halide
Pph3 + RX ---> (ph3)-P(+)-R
The Phosphorus has made a bond with alkyl and it has positive charge in it. Now comes BuLi which deprotonates the alkyl and make a complex with Li.
(ph3)-P(+)-R + BuLi -----> [(ph3)-P(+)-R(-)]Li
The alkyl now has a negative charge. Remember the the positive and negative don't make any pie bond due to presence of Li. Now it is ready to attack alkyl ketone.
This is what I learnt in my class. Hope you might find something new in it. It's hard to write structure here, you can draw them accordingly to understand better. Hope it helped!
Question, @7:45 shouldn't the resonance form of Ph3P have a positive charge under phosphorus since it has four bonds?
I think the phosphorus atom has five bonds, counting the sigma and pi bonds to the carbon atom separately. So the formal charge is #valence electrons - #bonds - 2*#lone pairs = 5 - 5 - 0 = 0.
This mechanism is like a dance. I love it.
5:01 for the mechanism
Hello, at 10:00, when forming the cyclo compound, when do I know the electrons are transferred from 1 bond to another bond or from 1 bond to an atom e.g. Oxygen / Carbon? Is there ant general concept I should be known about? Thanks
Tony Lee There are many different scenarios which control this, no single rule really, here though in your question, the two carbons are attracted because of their opposing electronegativoty and positivity. You also need to know carbon never has 5 bonds, so when this 5th bond is made, it must drop another to go back to 4, it chooses to break one of the bonds on oxygen because it tries to break a bond without loosing any atoms if possible, so if it broke any other bonds atoms would leave. Know this oxygen withdraws the electrons after the bond breakage, as it is more electronegative than carbon. This negative oxygen readily combines with the positive pph3, forming that structure.
i thank u saved my career in medicine test
Is it just me who love the sound of the pen tool hitting the surface😢
can you talk about the stabilized and non stabilized ylides?
If you haven't found the help, search the video, Knowbe, "witting reactions". @11-12:30. It helped me. :)
See my comment. You're higher level....I can tell--than someone.
Thank you so much pro you saved my time ❤
I am in class 11 th from India it is in our syllabus thank you
Real chemistry, awesome, thnx a lot ❤
just awesome as always ❤️👍
cis product is preferred, per my organic chemistry instructor and the textbook.
I strongly Recommend you to see 👇👇
ua-cam.com/video/tJHmnWxPMVE/v-deo.html
For witting reaction: 16:00 🖕🖕
Do see the lecture that I shared with you...You all will for sure understand much much better..
#PROUD TO BE INDIAN 🇮🇳💗💯
Thanks bro love ❤️ from india
Hey sir I have a query let's suppose we have 2 unsymmetrical carbonyl gp. which will gonna react then?
Could you do a video of the baeyer williger reaction? 🥺
Excellent explanation
Why can’t the ylide carbon take away α-hydrogen from acetaldehyde?
I notice you have p-c double bonds; why?
How can prepare 2-methylcyclohexanone from 1-methylcyclohexene?
YOU are GREAT !
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Sheer awesomeness. Thank you
Awesome!
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Thanks man!!!
It’s not correct!!! Yes you get a mixture but in the example of using a alkyl-Ylide you will get >= 90% Z alkene because it’s a labile Ylide. 50/50 would be only if you use a Aromatic ring or system as the funktional group of the Ylide. For E alkene you have to use very stable Ylides with EWG funktional groups on the Ylide!!!! 10:59
6:48
Thanks a lot
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