Zaitsev and Hofmann Elimination Products

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Sometimes you can get multiple elimination products from the same reaction, and we have to be able to name them. Not more nomenclature! Well, yes, kind of. But it's people's names. Zaitsev and Hofmann, to be precise.
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3 янв 2015

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Комментарии : 204

@CliffStamp 7 лет назад

Dave, appreciate how you explain from fundamentals why one product is favored, not just give some rule which appears arbitrary. This was always one of my biggest problems with Chemistry, it seemed to be a collection of rules with no coherent explanation.

@brightlandwitch 29 дней назад

yeah so much gatekeeping lol

@songohan393 4 года назад

I told everyone in my oc class about you every single of them are learning with your videos now :D

@ProfessorDaveExplains 4 года назад

thanks for spreading the word!

@alirezasadeghifar3815 2 года назад

@@ProfessorDaveExplains me too, they are all your recent subscribers, they love you man!

@sagar1326 5 лет назад

A friend told me about this channel, and what turns out is sir you are underrated.

@rudranshpratapsingh7761 5 лет назад

Sagarnil Chakraborty yeah really.

@emperorviktor3335 2 года назад

Thanks Chemistry Jesus

@jenniferhernandez2889 5 лет назад

I was feeling discouraged about organic chemistry until I met you!!! Thank you so much for all the work that you do!!! You are a true blessing for all the struggling college students :')

@bigpapaj2611 8 лет назад

You make things so easy to understand; you always explain clearly why things occur. THANK YOU!

@denerrodrigues9417 7 лет назад

Thanks for the quality of your videos! I'm from Brazil and many topics of chemistry, we suffer for not having quality video lessons as yours, thank you!

@faal1805 9 лет назад

You are by far with the most clear explanation. Very well done ! U have an extra subscriber today ;-)

@malenaramirez2705 10 месяцев назад

i didn't know i could understand organic chemistry until i found your video, i had to read the subtitles because i speak spanish but i understood everything !! thank you very much

@miriamramos8873 5 лет назад

love the visual explanation of the chair conformation and why one of the H is not available. You are the best thank you so much.

@sukainaalherz3554 9 лет назад

Thank you very much... you are highly organized when you explain with such great skills in addition to your knowledge that make all of what you said understandable and clear...appreciate your efforts.

@seanoggilrane4514 2 года назад

Love how helpful these videos are Professor! Keep up the great work

@alaminhossain5348 3 года назад

Your classes are awesome...my addiction to chemistry is increasing day by day ...thanks a lot sir 😍😍..and I also suggest all of my friends to watch your lectures for clear conception .

@gabe2029 5 лет назад

you are very clear at explaining, i will share your videos with my classmates. blessings.

@andersondemori7076 8 лет назад

oh thanks Professor Im from Brazil and your videos are so good, even they are in English.I understood everything about this organic reactions...tks a lot

@Jisescrait33 3 года назад

I dont know how i discovered your channel but im happy about that, my mother language is spanish and there's no organic chemistry videos with this quality at least on youtube! keep doing your stuff.

@Jisescrait33 3 года назад

when i said organic chemistry videos I mean organic chemistry videos in spanish languague

@shailendrasinghal684 7 лет назад

my professor explained the same topic for 2 to 3 days which u made possible in just 10 mintues...keep up the good work :D

@pranav_manoj 4 года назад

I cannot thank you enough for the awesome explanation !

@aswins2249 Год назад

That was such a good explanation. Crystal clear.

@josechemistryintamil11than53 3 года назад

Wow u cleared my doubts...thank u sir...each and every students ..can understand your teaching....many u tube i watched....but urs very crystal clear..not skipping any small points....thank u sir....from india....

@tarandeepsingh5571 3 года назад

he knows a lot about science stuff. professor dave explains everything!

@areejalsham6662 6 лет назад

I always try to find your videos when i study, you are the best ever thanks alot i wish you can do all the chm :(

@mehranmoshkelani90 8 лет назад

Thank you so much professor Dave.you are great.

@lukehigginbotham2823 6 лет назад

Earned a sub!! Thanks so much for the help man!

@lucasreddy1118 8 лет назад

sir it's 3-bromobut-1-ene. tanks a lot .. u r the best on RU-vid

@lisadinh 9 лет назад

Thank you professor Dave this cleared up a lot of things for me for my Ochem midterm

@PunmasterSTP 2 года назад

I know it’s been awhile, but how did your midterm go?

@njockify 6 лет назад

Thank you so much! I was struggling with this in class and you made everything so clear! thank you

@PunmasterSTP 2 года назад

How’d the rest of your class go?

@mykalmartin3573 4 месяца назад

very coherent explanations still relevant for OC

@katjaschneider5816 2 года назад

Gutes Video! I did understand it much easier than in the most german OC videos.

@depfro 9 лет назад

Very helpful. Thank you very much :D

@purplefalcony7127 3 года назад

I can't thank you more, for it's the first time I distinguish Zaitsev from Hofmann. I used to think they are the same person that refers to the same process. And now, I feel I might pass the exam.

@PunmasterSTP 2 года назад

How’d your exam go?

@purplefalcony7127 2 года назад

@@PunmasterSTP Of course I passed, and got more than expected marks. Can't thank Dave enough.

@mujeebkhan7713 5 лет назад

Thank you so much sir..... It help me a lot

@Anonymous-bz7ij 2 года назад

thanks sir for this wonderful lecture

@todayisdomingo 7 лет назад

Lmao, Nice intro, You won a Suscriber, a chemist student from Venezuela :D and thank you!

@Therockingww 5 лет назад

Thank you so much Prof. Dave :)

@healthyhappymind542 Год назад

Thank you so much Prof Dave, for finally making chemistry an interesting learnable system for me.

@ishankamapatuna5302 9 лет назад

Wow you are done great job sir thank u very much...

@scottcampbell1635 Месяц назад

Thanks for not just telling me what to do but WHY WE DO IT. My orgo professor is great but we're in an accelerated course so sometimes the "why" is missed. To me, I just can't do the "what" without the "why".

@mariamdiab3678 9 лет назад

YOU ARE A LIFESAVER! Thank you :)

@Whitedragon1250 2 года назад

and once again i learned more from a 10 min youtube video than from 1.5h lecture in school

@rohithnarahari9018 Год назад

Actually I was in confusion which will be major product but this sir made my life easier thankyou so much sir

@user-zw7po5xj6r 3 года назад

Why you deal with E2 you should select SN1 because it made us action +3

@djchemtalk2946 7 лет назад

Excellent episode....

@carlovaldes259 5 лет назад

Thanks , the best explication ever !!

@ShenelleTaylor 8 лет назад

thanks for the help !

@relaxingnature6438 8 лет назад

good teaching sir

@prashantyadav7272 3 года назад

This video needs to get more views

@Itharmomin_Vlogs 5 лет назад

Very well explaination

@BRo-it1jh 5 лет назад

Great video!

@MilitaryPoliceG795 Год назад

How can you have tetrasubstituted? Wouldnt there not be a beta hydrogen to produce the double bond?

@jacobc2378 5 лет назад

How am I learning more from a free video than I am from the college class I’m paying $thousands$ for?

@zahrajaffary3547 6 месяцев назад

so when do we use saytseff and when hoffman?

@johnmathew168 6 лет назад

Thank you so much 😊😊😊

@sachinpatel9372 4 года назад

By far the best ❤😘

@OVERDOSE 8 лет назад

amazing examples!!!! (:

@adityaagrawal5407 2 года назад

you literally saved my exams!!

@PunmasterSTP 2 года назад

How did those exams go?

@HarshRajAlwaysfree 4 года назад

Thanks professor ;)

@xdvfgxngfnf 8 лет назад

Hey Dave, Great videos. Could you possibly do a video showing this kind of problem except where the LG is equatorial and the chair must do a ring flip to do the reaction? Having trouble with that and I know that it will be on my final. Colin

@ProfessorDaveExplains 8 лет назад

+Colin McCorkle i will add it to the list! though it won't be in time for your final. happy to do Skype tutoring if you like.

@colinmccorkle1195 8 лет назад

+Professor Dave Explains Hey Dave, How much do you charge for the Skype tutoring? Colin

@chimp1143 9 лет назад

EXAMPLE OF NUCLEOPHILIC SUS REACTION 1.REPLACEMENT BY CN- GROUP RX+KCN---->RCN+KX WHEN AgCN IS USED IN THE PRODUCT WE GET RX+AgCN--->RNC+AgX (ISONITRILE) WHY IS THIS SO?

@yasmineshiraz3844 3 года назад

thank you so much

@hanankhalil1106 6 лет назад

Thank u so much🙏

@baileyb3050 Год назад

You are a lifesaver

@saimahmad4980 5 месяцев назад

Thanks sir

@paoboonjinnz 7 лет назад

thank you!! helpful

@gregoriocallone8330 4 года назад

Hello Prof. Dave. I'm following these tutorials right now. Very helpful. But sometimes I still have questions, and I dont know if you hang around these videos cause they are quite old. I'll try and ask them anyway. So my doubt about this is, in the examples part of the video, is there a specific reason why you would have us draw the chair for compound number 2 but not for number 1? Isnt that a cyclohexane as well? And isnt the carbon on the left of Br still a potentially working beta carbon? Ty so much man you know what you are doing and you are definately making me interested in the subject. Btw if Prof Dave couldnt answer maybe some1 else will, I would still appreciate the help.

@ProfessorDaveExplains 4 года назад

For the first one, the carbon on either side has both protons available for elimination, so it is a given that one of them will be in the proper orientation, we don't have to check. With the second, there is a neighboring substituent, so we have to look at the chair.

@inderveerchahal185 7 лет назад

God Bless this man

@robochibi 5 лет назад

Dude you are the best!

@haneenal-salihi 3 года назад

wow ...thank you ... grazie .,,,, شكرا

@meilanycaimares4046 6 лет назад

QUESTION - In the second portion of the video when you're explaining the first example - when the Bromine leaves the molecule why is there a methyl group in the first outcome? There was no carbon there before why is there one now? I hope I'm asking clear enough. Other than that amazing video! Thanks so much.

@ProfessorDaveExplains 6 лет назад

there was a methyl! it's the dash bond.

@JaSomAdAm 9 лет назад

Very good video you've done good job man but i got a question. According to reaction when bromcyclohexan is turned into few Hoffman products, as far as kinetics would drive this reaction, will there really be a double bond formed with that atom of Br? I mean wouldnt it rly prefer a double bond creation in the circle? Sorry if my question is explained in ur vid.

@ProfessorDaveExplains 9 лет назад

Adam mackovčin no double bond to bromine! bromine is the leaving group. a double bond will be formed between two carbon atoms.

@Anna-dc5oi 9 лет назад

where would the stability of an alkene with two methyls on one carbon and 2 hydrogens on the second carbon rank among these? (CH3)2-C=C-(H)2

@ProfessorDaveExplains 9 лет назад

Anna Kornak that would be a disubstituted alkene, i'm guessing because of sterics it would be less stable than trans-2-butene, and somewhat comparable to cis-2-butene, though i'm not sure with absolute precision whether it would be slightly more or less stable than cis-2-butene. i'll go ahead and guess slightly more stable since double bonds are shorter than single bonds.

@flowerchild7471 8 лет назад

Thanks so much your awesome

@quintonanderson5980 5 лет назад

Thank You!!

@watiskongchanpat3620 2 года назад

Does the symmetry effect it? (I mean like is only wedge Hydrogen gonna attacked by Nu?)

@FanOfRobert 8 лет назад

very good video

@siyabongankosi9956 6 лет назад

A legend describes what you are

@H.Mark. 6 лет назад

Oh my God! I understand why for the first time in my life!

@lucasyoshida1235 4 года назад

isn't the isopropyl in the axial position going to make this conformation reaction unfavorable and a slower reaction? Therefore having to do the reverse chair?

@ProfessorDaveExplains 4 года назад

but the leaving group must be axial, so it must be in that conformation, which means it will just be a slow reaction

@isabellaswan6905 2 года назад

tHIS dude's a literal saviour

@danielohearn5408 6 лет назад

Is there a mathematical relationship between the Hoffman and Zaitsev product distribution and the molecular weights of the bases?

@ProfessorDaveExplains 6 лет назад

not reliably, i wouldn't think, as it's all about sterics, and although lighter bases are usually less sterically hindered, that isn't a rule by any means.

@rxdsza 7 лет назад

Thank you so much :')

@ashleechadwick6392 7 лет назад

So I know when there is a tert-butyl group and you draw it in chair form, the tert-butyl is always in the equatorial phase. Why is the dimethyl drawn axial? (or does it not really matter?)

@ProfessorDaveExplains 7 лет назад

every chair has two conformations, and every substituent on the chair will be axial in one conformation and equatorial in the other.

@jonasmarqua5994 7 лет назад

Yes i had the same question...there are 3 substituents all in axial position....wouldnt it be too much unfavourable to switch to that position for the ring ? wouldnt it be almost as an anchor if you got 3 substituents in equatorial position ?

@harveyalram5393 Год назад

This guy is the goat

@lucasreddy1118 8 лет назад

sir what if 3-bromobut-ene undergoes elimination with koh?will it follow zaitsev rule?

@ProfessorDaveExplains 8 лет назад

where is the double bond? if it's internal you'll get the alkyne. if it's terminal, you'll get the conjugated diene. actually i suppose it must be terminal otherwise it would have to be 2-bromo, so yes you'll get the alkyne which i suppose would be considered the zaitsev product, although i don't think we would apply that nomenclature in that particular instance.

@shanemichael9011 5 лет назад

I love this well understood video and the ones on historical figures too. They are great Prof. Dave ! Anyway, while viewing this Hoffman/Zaitsev video I found it informative, but out of curiosity, I always wondered why the lone hydrogen attached to the Carbon holding the Halogen itself is never involved in any reactions where bases are grabbing protons. They only go after hydrogens on nearby Carbons. I would assume that there is one there since stable Carbons have 4 bonds. Maybe I am missing something.

@ProfessorDaveExplains 5 лет назад

good question! so the proton on the carbon that bears the halogen is not acidic, because if a base grabbed it, where would the resulting negative charge go? it would be localized on the carbon. only if a beta proton is abstracted can a pi bond form because it is the leaving group that is able to leave.

@shanemichael9011 5 лет назад

@@ProfessorDaveExplains Thanks so so much. I am a Man who always loved learning about what some people would call "the craziest things" !! Science is my favorite and my burning desire to learn is still with me even though my childhood days are many years gone. Thanks again Prof. Dave And for the informative videos ! ☺

@rrezartkrasniqi5578 3 года назад

du bist ein Ehrenmann

@prasadkulkarni7686 5 лет назад

Why did you put isopropyl group above?? What if ring flips?? Do we get same or different products??

@ProfessorDaveExplains 5 лет назад

that's the conformation from which E2 proceeds

@icemabubobub1578 Год назад

Shouldn't the isopropyl at 08:30 prefer the equatorial comformation ?

@ProfessorDaveExplains Год назад

yes but elimination can't proceed from that chair

@randomstuff4092 4 года назад

great Sir :-)

@PunmasterSTP 2 года назад

Hoffman? More like “You’re the man!” 😎

@carlosjenkins7882 9 лет назад

Why didn't you apply the anti-co planar rule to the first reaction..considering that they are both ring structures?

@ProfessorDaveExplains 9 лет назад

Rick Jenkins for that first ring i use the protons on either side that are anti coplanar to the leaving group, i just didn't examine the chair structures to prove it, since i went over that extensively in the "E2 on cyclic structures" clip.

@carlosjenkins7882 9 лет назад

Professor Dave Explains Thanks for the response. You have gained another subscriber!

@michaelwiles5363 6 лет назад

In the first example (9:00min onwards) why is the dashed hydrogen the one that gets eliminated for the Hoffman product? I thought that the proton that gets eliminated needs to be on an adjacent carbon and anti to the leaving group? thanks! :)

@ProfessorDaveExplains 6 лет назад

at the end with bromine and methyl on cyclohexane and methoxide going to zaitsev and hoffman? that proton is not on the dash, the methyl is on the dash! three hydrogens are on it, one will be anti at any given time.

@michaelwiles5363 6 лет назад

Sorry! my bad! I meant 6:00min. I have no idea why I put 9min. Its the first (top) example of two that you do. Thanks for coming back to such an old video. Im sure the answer is straight forward but I just cant see it :)

@allesklar8636 3 года назад

Greetings from Germany :) love these videos

@GreenMarble 8 лет назад

Can the example at 9:00 be Sn2 or E2? The carbon is only secondary, so both should work with the small strong base? Or is the ring itself just too hindered?

@ProfessorDaveExplains 8 лет назад

+Green Marble the steric hindrance from the isopropyl would certainly reduce the amount of SN2 but yes there could be some substitution. this is just examining the case where elimination occurs, which could be ensured easily by, say, heating the reaction vessel.

@GreenMarble 8 лет назад

+Professor Dave Explains Awesome! Thanks so much.

@DF-il4uu 8 лет назад

In germany we call it Saytzeff and Hofmann product. That's weird because they're actual names.

@manavshah6811 8 лет назад

Russian translation can be awkward and vary in various books and authors

@HrishikMukherjee 7 лет назад

Same in India !

@aayushsharma3655 5 лет назад

fellas the rule is called Saytzeff rule which was given by chemist Zaitsev.....so nobody is studying different

@avijitdey992 5 лет назад

@@aayushsharma3655 no. It is Saytzeff/Zaitsev/Saytzev's rule depending upon which language you speak. Zaitsev was his name in Russian but his English name spelling was Saytzeff and our education system is adopted from English thus we also call it Saytzeff rule. Open a Russian authored book and you'll see it as Zaitsev's rule.

@summerblanco6709 5 лет назад

continuity error! starts episode with red flannel on and ends with gray flannel?? Cmon professor dave!

@ProfessorDaveExplains 5 лет назад

oh the sign off is its own thing sillypants

@Lumax96 7 лет назад

Nice vid, but could you explain what secondary and primary protons are? Google didn't really help me on that one....

@ProfessorDaveExplains 7 лет назад

hmm that kind of terminology is not used very often, but i assume a primary proton is one found on a primary carbon, secondary proton on secondary carbon, etc.

@Lumax96 7 лет назад

That would make sense...came across this at like 7:28, but I think I get it with that explanation. Thanks!

@ProfessorDaveExplains 7 лет назад

oh hah, i forgot i said that! yeah i'm not sure how universal that language is but that's what i meant :)