Stereochemistry - A Simple Trick for Determining R and S

[@caryllabja]

thank you sooo much! just saved 4 hours of sleep bc of this vid

[@MasterOrganicChem]

You are so welcome!

[@yesha612]

Please can you show an example of one where H is in the plane of the pledge. I read your comment below about it, but didn't quite understand.

[@MasterOrganicChem]

Best trick is this: switch H with whatever is in the back ("wedged") then determine R/S. The "true" R/S will be the opposite of that.

[@anweshaguha7366]

+Master organic chemistry I have a question sir, I was taught that even number of rotations in a molecule doesn't affect it...but you made 3 rotations(in the longer method)....so does that change the optical activity of the original molecule?

[@Natson_45]

Wouldn't the back be on a dash instead of on a wedge?

[@laithacademy]

what if it was in the side

[@steved7777]

You're saving my chemistry exam, thanks!

[@MasterOrganicChem]

You are so welcome!

[@lailasamadi960]

You are the best. All ur videos help so much, I dont know how to thank great tutors like you!!

[@MasterOrganicChem]

Thanks! Upvotes and shares are always appreciated : - )

[@jimzomer3571]

Jij! Bent echt heel lief :) (you are really sweet ;)

[@duncsv5955]

dude you're the GOAT, literally made this concept so much easier. Thanks man!

[@MasterOrganicChem]

Thank you!

[@anizeer]

Literally...very helpful. Thank you is a small word to say.

[@MasterOrganicChem]

Glad it was helpful!

[@nicktumsampra]

So so helpful! I wish I'd found your page sooner!

[@MasterOrganicChem]

Samantha Kennett glad you found it helpful!

[@MakeupNFashionDiva]

You deserve a medal seriously amazing!

[@MasterOrganicChem]

Thank you!

[@Anzhela2]

Thank you!!!!!! This looks so much simpler now that I'm not under pressure to learn this! I'm still retaking my Chem 112 class to hopefully boost my GPA by bettering my Chem grade. I get this now! Yayay! I've struggled with Chem for a year now and am just now breaking through. Whew!

[@MasterOrganicChem]

You are so welcome!

[@MagiRaz]

Man, I missed one day of class to have a wisdom tooth pulled and it gives me hours of trouble. You have saved me.

[@MasterOrganicChem]

Hope you feel better with the tooth! Glad the video is helping with the missed class

[@elenag.2378]

you saved me! thank you soooo much

[@natopal0819]

Thank you! But what if H is in the plane of the molecule? Is there like a more general approach to this trick?

[@MasterOrganicChem]

You may find our membership useful, here's a short video it's only a few minutes. Hope this helps - bit.ly/2YctxPb

[@panizshafi3789]

Omg most useful Ochem video I have so far seen :) great job, thank youuu

[@AGreatDayForHockey29]

What if H is not in the front? What would you do if hydrogen was in the side position like where -CH3 and -Cl are in the example?

[@MANUALCHEMISTRY]

At that situation there's come two methods ,it depends on you whichever method you will find more convenient. Here I will discuss both . (1)As we all know hydrogen atom has lowest in priority so we rotate the H-atom till it reaches to dashed line. After that ,we simply rotate arrow from high priority group to low priority group . If the movement of an arrow is towards (a)clockwise direction=R &for (b) anticlockwise direction =S (2) Whatever H -atom be carried position we simply rotate the arrow from higher to lower priority group and hence we get either R or S. If H-atom is not at the dashed position then we have to reverse our previous nomenclature result.

[@22rnd]

he already answered to Kaustubh Tandon : Best trick is this: switch H with whatever is in the back ("wedged") then determine R/S. The "true" R/S will be the opposite of that.

[@ajaypatha1]

Could you please explain why Cl-C bond stayed the same during rotation?

[@ddk1018]

Try imagining the C-Cl bond as the axis about which the molecule is rotated.

[@anonanon-rc7ib]

@@ddk1018 but how do you know when to keep one of them the same and which one?

[@ddk1018]

@@anonanon-rc7ib in the case given in the video we have the H above the plane, and for determining whether the compound is R or S the group with the lowest priority (in this case, hydrogen) should be below the plane. So to do that we consider the C-Cl bond as an axis and we rotate the compound around it, so the C-H bond gets moved from above the plane to below the plane. Again we only did this rotation because we wanted to take the H behind. We wouldn't have to do that if the lowest priority group is already below the plane

[@ddk1018]

In brief, the bond which we select as the axis for the rotation of the compound remains the same

[@anonanon-rc7ib]

@@ddk1018 Thank you👍🏻🏆✨

[@Sarahh_]

What do we do if group 4 is not on a wedge or dash? I have my DAT in 2 weeks and need to know in case it pops up , thanks in advance!

[@mblackops2]

I am taking the DAT in a year and a couple of months from now. How was it? I am really nervous to take it, how did you do on it?

[@Sarahh_]

@@mblackops2 hello! you're doing good by being ahead of the game and thinking of the DAT a year in advance. tbh, it wasn't too bad. Practice is key. It's dependent on which subjects you are stronger in. For example, I really suck at chem and math - the exam was mainly Orgo, gen chem, math, bio. So I had to study a ton / practice since math and chem are my weakest. Bio was not too bad since it was my strongest. I got an 18 on bio the first time. Study tools I reccommend : DAT Bootcamp (helps get the basis/foundations down for like every subject- this is where I based my study notes off of) --- DAT Booster - for the PAT (especially) and I think its closer to the DAT than any other study tool tbh ---last thing : DAT Destroyer for the math and sciences (mainly math) . I believe with these 3 you will do really well. also, try to maintain a good diet during. my major mistake studying for the first DAT I took was not exercising like usual - it made me more stressed. Give yourself time to breathe and good luck! let me know if you have any other q's!

[@mblackops2]

@@Sarahh_ Thank you!! For the information, it’s really good to see what other people have to say about things I will have to do in the future. Makes you feel not alone and I appreciate that. And tbh I’m not thinking about it too much I just seen your comment on this video Becuz I have my first Orgo Exam tmrw and I was watching R/S configuration videos to help me 😂 May I ask did you get into Dental School? My sister is about to graduate college this semester but she’s taking a year off school after graduating to build her resume to apply at Medical school, it’s really a tough process

[@Sarahh_]

@@mblackops2 Orgo is not as bad as I thought it was when I was init undergrad! its actually just repetition. I wish I can go back and redo those classes to get better grades cause I took gen chem's 1 and 2, Orgo lab, Orgo 1 and 2 in my university and it was harsh. studying them again for the DAT made life easier , and things clicked (that didn't previously) you will do great on ur exam iA! actually, no I have the chance to get in now, but I decided to not continue my dental journey after working in it for 1 year - hands on experience is much diff than just studying it , so I think I actually saved myself the hassle in the long run (even though I wasted a lot of money and time for the exam :(

[@shahad-ty9tz]

we trace the line based on what? if it is 1,2,3,4 in order then it's R?

[@mw33213]

Thank you so much! :) So you can really just redraw the skeleton of the bonds and rotate the substituents around until the lowest priority is in the back? That seems too good to be true lol.

[@MasterOrganicChem]

You are so welcome!

[@nhazarr]

This is so clear. Thank you

[@yasmin90s]

what if H is just on a normal line, do we still switch?

[@akomonehmodestine3317]

Wow this was very helpful, I now know how to assign s and r configuration 🙏

[@novaop7776]

Thank you this helped me a lot, much appreciated!

[@MasterOrganicChem]

You are so welcome!

[@abdullahalrajhi9674]

What if there is another atom in the back and ranked 2 or 3, do you need to flip it over from S to R or what ?!

[@sunnyangel12]

amazing, thank you so much!

[@harshitpatni5040]

Thanks a lot !!! Very Helpful

[@SameerShaik03]

how to locate wedge and dash if we dont konw about them

[@kimberlygoethals4306]

this helped me a lot :)

[@rosebooklover]

‌That was really great thanks a lot❤

[@kingo717]

Please answer whoever know!! Will this trick work even if the number 4 atom is not wedged but rather on a line ( on the plane of paper?) Usually i see people use this trick when the number 4 atom is on a wedge but what if it was on a straight planar line? Thank you in advance!

[@aswin8063]

Same doubt

[@curtpiazza1688]

Neat trick....thanx!

[@MasterOrganicChem]

You're welcome!

[@emely1070]

Thank you so much for this! I was confused for hours and now I understand! :)

[@MasterOrganicChem]

Glad it helped!

[@annaencomienda2863]

This is awesome. I get it now

[@ellaperizzolo9163]

thank you!!

[@MasterOrganicChem]

You're welcome!

[@mostafa_Mahmoud99]

Thx bro it it's still useful ❤

[@prettyangel2530]

Than you so so much

[@MasterOrganicChem]

You're welcome!

[@winproduction7585]

Thank you.

[@meghanap.996]

you saved me dude

[@rishinjeenu8113]

The trick is very good sir... Hats off... :)

[@Matimutheone]

Thanks

[@MasterOrganicChem]

You're welcome! If you found this video helpful, Our MOC membership has a lot to offer. Check it out here: bit.ly/2YctxPb

[@siddikabegum393]

Wow thank you so much!! Bond rotations are so tricky you've helped so much

[@MasterOrganicChem]

You're so welcome!

[@tiff-amberpaz6484]

I didnt get sleep last night and I passed out in class so thank you for explaining this

[@MasterOrganicChem]

You're very welcome!

[@jowelojong3161]

This is the best 🙈🙈

[@MasterOrganicChem]

Thank you!

[@Xplosiv3s]

if you don't move the methyl group, but move all the other groups it doesn't work. In the video you moved all the groups except the chlorine group and it worked. Is it just trial and error?

[@kkkkkkkkkk955]

this is very helpful!! thanks!

[@MasterOrganicChem]

You are so welcome!

[@hashinimallawaarachchi3502]

Much love ....

[@MasterOrganicChem]

Glad it helped! I would like to invite you to check out our monthly (no long term commitment) membership with over 1500 quizzes, flashcards the reaction guide and more. Here's access: bit.ly/2YctxPb

[@marymessam2435]

Thanks , it was really helpful 😃

[@MasterOrganicChem]

Glad it helped!

[@cherrryblossom31]

I love your videos, i would fail my organic chemistry exam if it wasn't for you!. THANK YOU!!

[@MasterOrganicChem]

Thank you! You are so welcome!

[@MuhammadIdrees-c9f]

Nice, thanks. But you did not change the position of Cl and methyl group when you flipped the compound.

[@themoviesounds]

really helpful!!! thank you!!

[@MasterOrganicChem]

You are so welcome!

[@farahsukkari2402]

You are amazing! Thank you.

[@jaws0222]

So I'm guessing this doesn't work if the hydrogen is in the plane of the page, only when it's in front/towards you?

[@MasterOrganicChem]

Correct - in the case where H is in the plane of the page I would recommend swapping the H with whatever is the dash, and then determining R/S normally. Your "real" R/S will then be the *opposite* of that. This always works!

[@MasterOrganicChem]

Yes. In practice, however, it's fairly rare to have hydrogen in the plane of the page, as the alkyl chain is usually in these positions.

[@edenlema5181]

Bless you.

[@abhishekparsi3527]

What if the H is in the plane of the page?! Plz help I have an exam in 2 days

[@ramonalup4296]

very helpful, thank you

[@MasterOrganicChem]

You are so welcome!

[@MasterOrganicChem]

I'm not sure I understand what you mean. Could you explain in more detail?

[@aaronschmidt5662]

The wedge on the hydrogen is pointed the other way, does that make any difference or was it just drawn funny?

[@aaronschmidt5662]

Also what, we ignore the chlorine when moving things around but now all of a sudden when counting its included?

[@nbjrd]

hey thanks for the vid. are there exceptions in for wich the fast way does not work because i use it lot of time and sometimes it doesn't fit with the slow way. Thank you greetings from Switzerland. (My test is next week)

[@ananyasharma3096]

Are there any situations where this trick won't work or is it fullproof?

[@thecoreybrown]

So why on the bottom molecule you couldnt go clockwise at the beginning before you just flip it? because CH3 is just a line and so is CL. so why did you go counterclockwise going from 1-2-3-4? couldnt you go clockwise 1-2-3-4?

[@arjuscarlet55555]

Great video thanks a looooooooooot.🖤

[@souravkumar2522]

Nice video sir

[@haseeenaabdulrazak4692]

Put least priority group in the back,if it is not determine the configuration and reverse it

[@alhassanmichael306]

Sooo good thanks 👍

[@JenniferJR-kt7iz]

Amazing

[@kjaideep]

Hi sir why aren't you uploading the videos pls try uploads atleast 1 video for 1 week because it will be helpful for many students of iit aspirants Thank you From India 🇮🇳

[@MasterOrganicChem]

Will upload soon

[@kjaideep]

@@MasterOrganicChem thanks for replying sir :)😊

[@ghostmedic86]

On my homework, which is significantly harder than any example I can find online or which was given in class, all we are given is a name. (3R,6R)-3-bromo-6-methylcyclohex-1-ene. How in the world do you determine which is forward? IDK lost.

[@madebysammy2000]

to this day, nobody seems to answer the question to Hydrogen being on the plane.

[@MasterOrganicChem]

You may find our membership useful, here's a short video it's only a few minutes. Hope this helps - bit.ly/2YctxPb

[@madebysammy2000]

@@MasterOrganicChem thanks but no thanks. An answer is all I need.

[@ktyt96]

question again what if hydrogen is not above or below the plane of paper but on it ???

[@rlboy3849]

lovely, thanks a lot

[@hmmmmm4771]

Thankyou!!

[@MasterOrganicChem]

You're welcome!

[@aiyoungboy4484]

Skip to 3:45

[@MasterOrganicChem]

You need to be shown in which direction they go, or to be told that the stereocenter is R or S. If you are not given this information then it is typically assumed that the molecule is a "racemic mixture" with equal amounts of both configurations.

[@mattandlaurabaker8253]

Are you saying that the "front" and "wedge" are the same thing?

[@morgankappa5522]

Wedge refers the back, front is just front.

[@shlokamsrivastava6782]

Subscribed

[@thearmchairtraveller6492]

Neat trick!!!

[@22rnd]

that was very helpfull !!! :)

[@MasterOrganicChem]

You are so welcome!

[@12wholepizzas13]

What is r and s

[@Farah95]

omg I finally understand this shit! Thank you!

[@MasterOrganicChem]

You are so welcome!

[@nickb3221]

What if #4 is in the plane?

[@Xplosiv3s]

It doesn't work if you fix the CH3 and rotate the rest

[@ritik2028]

Thnx siR ResPecT frOm INDia

[@tfoprincess]

hahaha. I went to a school called RNS. I wonder why we never made that joke when we were learning this XD because R and S sounds like R n S which is RNS LOOOOL

[@MuhammadAli-fu5dt]

But what if H is in the plane

[@MasterOrganicChem]

You may find our membership useful, here's a short video it's only a few minutes. Hope this helps - bit.ly/2YctxPb

[@abdouderg2523]

What if its in the side this is the so important here

[@danieldaniel987]

you can skip the first 4 min it's just background

[@Ljumy]

i'm confused a little bit. I try to draw fisher projections for this example and everything goes wrong...😂

[@Mfsitsmatz]

In fisher projection vertical line represents backward direction away from us which is simply equivalent to a dash bond... So if 4 th group is in vertical line ur answer will be according to clockwise or anticlockwise direction as normal case... But if 4th group (H) is in horizontal line jusy flip the direction and ur answer will be not the same... If it's coming r normally and 4th grp is in horizontal line the answer will be s not r... Although I'm telling u this a little late like 2 years late😂👍

[@aswin8063]

@@Mfsitsmatz hey should we flip it when 4th group is in horizontal line or only when it is forward/dark wedged?

[@keerthikakeerthika2241]

Clearly u should tell about ple I can't understand.. can u tell start from basic..ple 😁

[@carolenasr3235]

Why did I not just think of this?? Loll

[@sahildhindsa8763]

It would be better, if you actually showed us...

[@MasterOrganicChem]

You may want to check out our month-to-month MOC membership for access to over 1500 quizzes, Flashcards, the Reaction Guide, and more. Check it out here: bit.ly/2YctxPb

[@SCIENCETECHOLOGY]

Wht the fuch this is really annoying version of you tube

[@thenri1410]

Angrejiii ....kyoo hindii bolo naa

[@Shogun507]

A North Indian asking an American to speak in Hindi lmaooo

[@guljafari3269]

thank you- very helpful video

[@MasterOrganicChem]

You are so welcome!

[@rafaeltavarez4025]

Thank you for this!!

[@MasterOrganicChem]

You are so welcome!

[@jo-jr2dv]

thank you!!!