but for sn1 100% racemization is not observed practically because nucleophile starts attacking the substrate before the formation of carbocation therefore we get more no. of inverted product( stearically unhindered ) may be regioselective be the reason...
but for sn1 100% racemization is not observed practically because nucleophile starts attacking the substrate before the formation of carbocation therefore we get more no. of inverted product( stearically unhindered ) may be regioselective be the reason...
@@PunmasterSTP Yep, and with a solid B thanks in part to these videos! The professor I had believed in the "flipped classroom" method, which has little direct instruction. And that is what I needed. These videos helped break down difficult concepts and get me through O-chem!
In this reaction though, wouldn't the chloride leaving group shield one side of the carbocation as it leaves? If that's the case, once water attacks the carbocation one side of attack will be preferential due to the shielding from the leaving group. I think this means that a SN1 substrate that generates a chiral product actually wouldn't form a racemic mixture (50/50 mix of enantiomers), but would instead form more of the product that results from addition of water to the unshielded side of the carbocation and much less of the product resulting from addition to the shielded side. In the example in the video, though, it wouldn't matter because a tert-butyl chloride shouldn't form a chiral molecule in SN1.
Shizzan Reynoodles i'm not aware of any such shielding effects, i only know SN1's to be completely unspecific in terms of stereochemistry. for the carbocation to be completely planar, there must be no remaining interaction with the leaving group, so it must be equally available on both sides for substitution, otherwise if there was still interaction with the leaving group it would have some SN2 character. of course there are many reactions that are truly somewhere in between SN1 and SN2, it gets a little messy.
You are completely right Sean, it wouldn't be a complete 50%/50% racemic mixture! Rather that the product is approximately 80% racemized and 20% inverted
The leaving group shields one side of the carbocation intermediate from reaction with the nucleophile, thereby leading to some net inversion of configuration rather than complete racemization
why... have i not found your channel earlier... I would've passed my exams on first try and not be struggling so much for so long to now.. somehow try to scrape up my knowledge after corona nirvana xD ... but well at least now. thank you sooo much I feel if I study with your videos I hav a chance of passingggg!!!
So cool channel! Everything is explaned on this channel, how everything works so even I (14 year old boy) can understand how does biochemistry works. Thank you for making so great videos.
@@PunmasterSTP Hello. Its been going great. I am just finishing secondary school and then I am planning to go to university. I will go to faculty of applied science in Pilsen.
So the example reaction shown in this video doesnt produce a pair of enantiomer because its leaving group is not attached to a chiral center right? (since the C atom at center is not attached to 4 DIFFERENT substituents)
I thought so too! In his example there's no stereocenter but he's telling us that in general you should see if the reaction has produced a stereocenter and if so, there would be a 50/50 mix of the products. Important note for this video..
Dear Professor , I have a question. Why negative charge stabilizes the carbocation? Isnt this negative charge a trouble for nucleophile itself carrying a negatie charge with electrons? what is actually meant by "stability" of carbocation? thanks for your video!!!
I'm sorry mate, I know it's too late! Carbocation is stabalized by electron donating groups via eitger of one of the process such as Inductive effect,Hyperconjugation and offcourse the Mesomeric effect. Coming to your question A negative charge would never stabalize a Carbocation till it is not in conjugated system! Which is one of the conditions for Resonance effect! Hope this helps
a good question! yes it is due to interactions with solvent particles, which is why these kinds of mechanisms are best suited for polar solvents. halogens are quite polarizable, and if they collide with solvent particles in just the right way, the attraction can be enough to break the carbon-halogen bond, but this is an endothermic step, and the rate-determining step, it's very slow and unfavorable.
I have a question sir! can you please tell, how is %age racemisation depending on the leaving grp. ability and stability of carbocation! waiting for your answerb
l and d are 50% 50% in recemic mixture and recemic mixture is not polarise light to right or left and u say 50%/50% R and S confrugration i dont understand professor dave.??
How is the intermediate so different and why does water attack? Is there an equation or something like a question to show that water has to attack? I don’t understand :(
well it doesn't have to attack, the leaving group could get back on, there could be elimination, it's just one of the things that can happen. and by tweaking reaction conditions you can get it to happen preferentially.
please help me, this is the one little thing that keeps annoying me because i can t understand why it wouldn t happen if the oxigen pulls so hard on the shared electrons, maybe it repells the chloride..maybe it s a more stable final product this way, i just can t find the answear. Thank you!
Professor Dave Explains And so if a very strong base would deprotonate the alcohol what would happen next can be a separate reaction from Sn2/E2? I mean it can as well make a Sn2/E2 reaction if the base it s Na Oh, considering oh- wouldn t be hindered by any sterical repulsions because it s so small ,so my question is can there also be a secondary reaction and by 'miracle' form an ether or something, like having the deprotonated alcohol interacting with the alkene in the solution in any strange way.Why isn t that possible professor?
because when the leaving group leaves, it takes the electrons in that covalent bond with it, so carbon loses an electron domain! with only three remaining, trigonal planar is the best geometry. check out my general chemistry tutorial on VSEPR theory for more help with this!
I’ve got some FREE resources to help you ace OCHEM 1 this semester: chemmunity.info/dave
but for sn1 100% racemization is not observed practically because nucleophile starts attacking the substrate before the formation of carbocation therefore we get more no. of inverted product( stearically unhindered ) may be regioselective be the reason...
sir please correct me if I'm wrong
Your videos helped me get an A in chemistry and because of my grades i was accepted into medical school. :D thank you professor Dave.
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THEsweetums wow congrats!
THEsweetums How is mes school going. My mes school will start in a few weeks and I am kinda nervous.
How`s med school treating you?
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I know it's been a long long time, but I just came across your comment and I was curious. How did the rest of your classes go?
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Professor Dave proves that we’re all paying too much money for college.
more clear and concise in 3min than my profs' multiple hour long lectures.
but for sn1 100% racemization is not observed practically because nucleophile starts attacking the substrate before the formation of carbocation therefore we get more no. of inverted product( stearically unhindered ) may be regioselective be the reason...
Hi Professor Dave, I'm Student Dave. Thanks for making these short and sweet. Appreciate the knowledge! Might just pass O-chem now!
I know it's been a long long time, but did you pass ochem?
@@PunmasterSTP Yep, and with a solid B thanks in part to these videos! The professor I had believed in the "flipped classroom" method, which has little direct instruction. And that is what I needed. These videos helped break down difficult concepts and get me through O-chem!
@@maximussarcasticus1312 I'm really glad to hear that! How'd the rest of college go?
@@PunmasterSTP Long journey. Still going. Love learning science stuff!
@@maximussarcasticus1312 I'm glad to hear it, and personally I'll always love learning science stuff!
Thanks Professor Dave, your videos help a lot! I will share your videos with students who struggle with O-Chem!
man you're the best! thanks for always making exactly the videos i need! they're easy to watch and its straight forward!
Simply explained..... A massive concept explorer... Thnx a lot ...professor Dev
Professor Dave, thank you for all of these tutorials!
As being physicist, I appreciate that molecular geometry approach.
What type of physics do you do? Do you do research, and if so, how is it going?
SN1? More like "Great content? This is definitely some!" Thanks again for making so many videos that convey so much knowledge and understanding.
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Love the videos, any chance you could make a spectroscopy tutorial?
Kyle K in my next update I plan to include tutorials for NMR spectroscopy, and possibly IR and mass spectroscopy as well. Thanks for watching!
In this reaction though, wouldn't the chloride leaving group shield one side of the carbocation as it leaves? If that's the case, once water attacks the carbocation one side of attack will be preferential due to the shielding from the leaving group. I think this means that a SN1 substrate that generates a chiral product actually wouldn't form a racemic mixture (50/50 mix of enantiomers), but would instead form more of the product that results from addition of water to the unshielded side of the carbocation and much less of the product resulting from addition to the shielded side.
In the example in the video, though, it wouldn't matter because a tert-butyl chloride shouldn't form a chiral molecule in SN1.
Shizzan Reynoodles i'm not aware of any such shielding effects, i only know SN1's to be completely unspecific in terms of stereochemistry. for the carbocation to be completely planar, there must be no remaining interaction with the leaving group, so it must be equally available on both sides for substitution, otherwise if there was still interaction with the leaving group it would have some SN2 character. of course there are many reactions that are truly somewhere in between SN1 and SN2, it gets a little messy.
+Shizzan Reynoodles yeah I agree with you
You are completely right Sean, it wouldn't be a complete 50%/50% racemic mixture! Rather that the product is approximately 80% racemized and 20% inverted
The leaving group shields one side of the carbocation intermediate from reaction with the nucleophile, thereby leading to some net inversion of configuration rather than complete racemization
dude no joke, you're helping me understand so much topic
why... have i not found your channel earlier... I would've passed my exams on first try and not be struggling so much for so long to now.. somehow try to scrape up my knowledge after corona nirvana xD ... but well at least now. thank you sooo much I feel if I study with your videos I hav a chance of passingggg!!!
Professor Dave you're an absolute legend sir!! Thank you!
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This channel makes my life so much easier
So cool channel! Everything is explaned on this channel, how everything works so even I (14 year old boy) can understand how does biochemistry works. Thank you for making so great videos.
That's awesome! I know it's been a long time, but I just came across your comment, and I'm curious about how your education has been going.
@@PunmasterSTP Hello. Its been going great. I am just finishing secondary school and then I am planning to go to university. I will go to faculty of applied science in Pilsen.
@@tomaspecl1082 That's awesome! I'm really glad to hear it!
Thank you prof.Dave your videos are great
So the example reaction shown in this video doesnt produce a pair of enantiomer because its leaving group is not attached to a chiral center right? (since the C atom at center is not attached to 4 DIFFERENT substituents)
I thought so too! In his example there's no stereocenter but he's telling us that in general you should see if the reaction has produced a stereocenter and if so, there would be a 50/50 mix of the products. Important note for this video..
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Dear Professor , I have a question. Why negative charge stabilizes the carbocation? Isnt this negative charge a trouble for nucleophile itself carrying a negatie charge with electrons? what is actually meant by "stability" of carbocation? thanks for your video!!!
I'm sorry mate, I know it's too late!
Carbocation is stabalized by electron donating groups via eitger of one of the process such as Inductive effect,Hyperconjugation and offcourse the Mesomeric effect.
Coming to your question
A negative charge would never stabalize a Carbocation till it is not in conjugated system! Which is one of the conditions for Resonance effect!
Hope this helps
Is it always true that SN1 will undergo an acid base reaction or is only for solvolysis? ex: Tertbutyl Bromide + OH- -> ?
we can't make such generalizations, SN1 is just a mechanism, many different reactions follow this mechanism
Why does the oxygen have positive charge btw? It has two lone pairs on its own.
congrats for being a part of the orgo holy trinity of youtube
Why does the Chlorine just leave? What is the solvent doing specially which causes that?
a good question! yes it is due to interactions with solvent particles, which is why these kinds of mechanisms are best suited for polar solvents. halogens are quite polarizable, and if they collide with solvent particles in just the right way, the attraction can be enough to break the carbon-halogen bond, but this is an endothermic step, and the rate-determining step, it's very slow and unfavorable.
+Professor Dave Explains Thank u so much I too had same question!!
I find it funny how Sn1 reactions are in my syllabus but I don't understand half of the words you said.
watch the SN2 video first, i define the terms
I have a question sir!
can you please tell, how is %age racemisation depending on the leaving grp. ability and stability of carbocation!
waiting for your answerb
The ending of the song was wicked!
Wouldn't the Cl- make HCl from the H20+?
+Mayo taizou HCl is a stronger acid than H3O+, so a chloride ion won't be basic enough to deprotonate hydronium, at least not appreciably.
Sn1: One reaction has happened. Two more to go. SN2: Two reactions have happened. One more to go.
l and d are 50% 50% in recemic mixture and recemic mixture is not polarise light to right or left and u say 50%/50% R and S confrugration i dont understand professor dave.??
L and D is terminology that specifically applies to sugars, in general stereocenters are either R or S
Rate of sn1 mechanism only depends upon the concentration of substrate ???? Justify
How carbocation has sp2 hybridized orbitals ????
it only has three electron domains
I love you Professor Dave
Love these vids!!
How is the intermediate so different and why does water attack? Is there an equation or something like a question to show that water has to attack? I don’t understand :(
well it doesn't have to attack, the leaving group could get back on, there could be elimination, it's just one of the things that can happen. and by tweaking reaction conditions you can get it to happen preferentially.
Thanks Mr.Dave
you are great person >>thanks
i literally love you thank you
It feels illegal to understand something in under 5 mins than my professor does in 90 minutes
What exactly is the difference between sn1 and E1 ?
One is substitution, the other is elimination! Huge difference.
Thanks a lot Dave ♥️
Wait a minute... I don't get why can't this reaction proceed as Sn2, like in the previous vid?. Or these two are just competing mechanisms?
nucleophile isn't strong enough to attack substrate
Not Giggs?
what if we had an (Ch3)³C-Oh , It would be possible for an Cl- or any strong base to steal the H from that Oh?
please help me, this is the one little thing that keeps annoying me because i can t understand why it wouldn t happen if the oxigen pulls so hard on the shared electrons, maybe it repells the chloride..maybe it s a more stable final product this way, i just can t find the answear. Thank you!
a strong base can deprotonate tert-butanol, sure, but not chloride.
Professor Dave Explains Is it because Chloride is stable by itself? And also thank youu very much btw 👌👌
yep, HCl is a strong acid so chloride is an extremely weak base
Professor Dave Explains And so if a very strong base would deprotonate the alcohol what would happen next can be a separate reaction from Sn2/E2? I mean it can as well make a Sn2/E2 reaction if the base it s Na Oh, considering oh- wouldn t be hindered by any sterical repulsions because it s so small ,so my question is can there also be a secondary reaction and by 'miracle' form an ether or something, like having the deprotonated alcohol interacting with the alkene in the solution in any strange way.Why isn t that possible professor?
why carbon changes it's state of hybridization from tetrahedral to planar? 😕
because when the leaving group leaves, it takes the electrons in that covalent bond with it, so carbon loses an electron domain! with only three remaining, trigonal planar is the best geometry. check out my general chemistry tutorial on VSEPR theory for more help with this!
hey cant understand at last how h2o remove H and oH form plz expln
well it's no different from the water on the substrate, they just collide and proton transfer occurs!
Thank you man your areal life saver😍
thanks a lot
einstein was wearing the same suit the life and you change shirt just to say "thanks for watching?
I said the sign-off once and pasted it at the end of every video. It's called efficiency.
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Professor Dave Explains I challenge you, if you solved any question of "IIT JEE advanced " examination ( chemistry section) ,I will gift you lambo.
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the carbocation intermediate shouldnt have dashes or wedges, its trigonal planar (flat).
it is drawn in the plane perpendicular to the plane of the board to better show the nucleophile attacking from either side of the intermediate.
oh i see it now thanks
this is not the video i expected when i clicked on it xD this isnt SpaceX. lol
To be honest I don't understand what you're explaining
Thanks
You are a second version of sal khan
Sir how can I Improve in chemistry I m really facing great difficulty in scoring marks in chemistry since class 11 th sir Please help me!!!😣😣😣
just watch all my tutorials! check out the playlists on my home page.
Professor Dave Explains thank you sir you replied I'll do so as you told
Where is SN2?
that's got its own tutorial, check out my organic chemistry playlist for all of them!
I genuinely wish I found this year's ago.
awsome stuff
Good
jee advanced ?
what is racemic mixture
a mixture of stereoisomers
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