Fischer Projections How to Draw and Interpret for Single and Multiple Chiral Centers

leah4sci.com/f... Presents: Fischer Projections for MCAT Organic and Biochemistry
📺Watch Next: How to Draw Fischer Projections • How to Draw Fischer Pr...
Catch this entire video series + practice quiz and cheat sheet on my website: leah4sci.com/f...
Video 1 (of 5) in the Fischer projection series, this video explains what to look for and how to draw Fischer Projections
Note: @11:56 These would not be chiral carbons because the carbon is attached for three of the same side groups. Neither of the molecules that appear on the screen at 10:46 have chiral centers, as neither have carbon atoms that are surrounded by 4 unique substituents.
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[@anashavshishvili965]

It's 2021 and your videos still help students, thank you Leah!

[@Leah4sciMCAT]

Happy to help!

[@soulwave7237]

Each of these video series are excellent! Very well thought out and simplified - the use of colours, variety of examples, organization of each series...The effort to make them and share them is very appreciated!

[@Leah4sciMCAT]

Thank you very much for those kind words! You are very welcome

[@dionysus9876]

This is a wonderful explanation of Fischer projections. So much detail! I really appreciate this video!

[@Leah4sciMCAT]

I'm glad you liked it! You are very welcome :)

[@ashrafal-junaid3864]

just discovered your channel. its kinda awesome that your videos have helped students for more than five years. i very much appreciate you. thank you so much!!

[@Leah4sciMCAT]

You're very welcome!

[@Desiboys6]

omg u r a lifesaver. without u my finals would go outta the window. thanks a lot

[@Leah4sciMCAT]

Glad I could help!

[@calvinklein6903]

thanks for clearing-up this topic for me...I'm so grateful. KEEP IT UP,LEAH!

[@Leah4sciMCAT]

You're very welcome!

[@imenehk2221]

Wow god bless you, you just saved me! Your channel is gold I like all the video's that I've watched until now but the fisher projection was just the most difficult part of organic chemistry and you explain it very well! THANK YOU!!!!

[@Leah4sciMCAT]

Great to hear that! Glad the video helped you understand the topic much better. Thanks for the feedback and you're welcome! :)

[@michaeldepauw7446]

I really like the opening a book idea for manipulating molecules into "Fischer Projection form." I work for a college and am putting together a website to help students. In the useful videos section, I often like to use your videos because of their clarity and quality. Thank you for making them!

[@Leah4sciMCAT]

You're very welcome

[@Daystar_uni_ad]

the whole book example totally lost me

[@Leah4sciMCAT]

At which point in the video?

[@Daystar_uni_ad]

from 2:23 :(

[@Irelia05]

Me too! :( Please Leah can you explain how to imagine the book?

[@NguyenLinh-ng7ol]

mee too. i can't imagine how the book works

[@FlowerTower]

She answered under a different comment: "Of course! Imagine that the molecule with chiral center C is a closed book lying on a table. The spine of the book would be the line from A to C to E. The front cover of the book would be D, and the back cover of the book would be B. To open the book, the front cover D would be swung towards us and to the left. Now we have both front cover D and back cover B coming towards us in a horizontal line, and the spine of the book is running in a vertical line between D and B. Now in reality, a book would lie on the flat plane of a table. In a Fischer projection, the horizontal line is projected out of the plane (towards us), and the vertical line is projected into the plane (away from us). The analogy is limited, but helps visualize the movement of the molecule into a Fischer format."

[@berylosuma7019]

In the horizontal line; how do I know which molecule goes to the right and which goes to left ? In the vertical line; how do I know which molecule goes on top and which on the bottom?

[@Leah4sciMCAT]

As long as you maintain the proper configuration at the chiral center, it really doesn't matter. For example, I could take any one of these molecules, rotate it 180 degrees along either axis, and that wouldn't change the identity of the molecule. For help with questions like this and more, I recommend joining the MCAT Study Hall. For more details, visit join.mcatstudyhall.com/ or contact me through my website leah4sci.com/contact/

[@sadiamoumita2265]

That little bowtie trick has been an excellent help! I think of it every single time I look at a Fischer projection now

[@Leah4sciMCAT]

Awesome, so glad it helped you!

[@purvadevkar222]

Thanks ,this really clears up my concept and I love your accent

[@Leah4sciMCAT]

Happy to help, and thanks!

[@yushiliang8679]

Thank you thank you sooo much for making this video. You are awesome!

[@Leah4sciMCAT]

Aww, you're so welcome!

[@sarthaksharma9322]

Hello, great video and explanation but I jut wanted to ask that at 11:59 is the carbon in the 1st structure chiral? because two methyl groups are attached to it how can it be chiral?

[@mrpee2482]

Even the second one 🤔

[@Leah4sciMCAT]

Great catch, please see the video description.

[@AryanSingh-eq2jv]

I've been sitting here trying to visualise this with four of my pencils and didn't get it This video helped me tons I cannot express in words my love for this video and you 😔

[@Leah4sciMCAT]

Happy to help!!!

[@danielajbq]

I cant thank you enough for these videos!!!!!!

[@Leah4sciMCAT]

you're very welcome!

[@khushbu6845]

Thank you so much your make it seems so easy!!!

[@Leah4sciMCAT]

Happy to help!

[@seylaadam7605]

great teacher!

[@Leah4sciMCAT]

+Seyla Adam thank you

[@wafaah7903]

that was amazing! thankyouuu

[@Leah4sciMCAT]

Aww, you're so welcome!

[@elsaasres9478]

Thanks so much this is the best video for me,

[@Leah4sciMCAT]

I'm so glad you liked it!

[@apurvakmr]

You are a Goddess, no less. Your vedios are probably the best I have seen on the subject.

[@Leah4sciMCAT]

Glad I could help, but I doubt I'm a deity

[@ipuffyface]

thank you so much Leah💗

[@Leah4sciMCAT]

You're so welcome!

[@durgeshwarinalamwad9879]

Really nice video for clearing concepts

[@Leah4sciMCAT]

Thank you for your kind words

[@tharushinisansala2147]

thank you soo much great explanation...

[@Leah4sciMCAT]

You are welcome!

[@alchemist68plus14]

yo Leah I lost my initial undestanding after watching your book example can teach to rotate by maintaing a 2 d model

[@alchemist68plus14]

hey don't bother completely understood the 3rd time

[@Leah4sciMCAT]

Yay! Glad you got it!

[@iBuyBitcoin]

Wow thank u so much, that bow tie on the stick man really helped lol

[@Leah4sciMCAT]

Glad it helped!

[@maryambelhajji2483]

How do we go from a cram representation to a Fischer one?

[@Leah4sciMCAT]

I'm not familiar with cram representation

[@SilverBlade15]

How does one do fischer projections for simple, non-sugar ring structures though? Like methylcyclohexanol?

[@Leah4sciMCAT]

It’s possible to draw a cyclic Fischer projection by using a sort of box to connect carbons along the central carbon spine. However, it’s not a preferred method. It’s much more preferable to convert the structure to a Haworth projection, which does a better job of illustrating the orientation of the carbon substituents. Thanks for watching!

[@hennaali5814]

I thought the highest priority group had to be on top whenever you're assigning configuration on a Fischer projection. Why wasn't that applied here?

[@Leah4sciMCAT]

Actually, the highest priority group should be coming out of the page. Placing it on top of a Fischer projection would mean it's going behind the plane of the page. For my Fischer Projection stereochemistry trick, make sure to watch the following: kzbin.info/www/bejne/opeZmX94oZuqrtE

[@strugglingcollegestudent]

here reviewing cuz we're doing fishers again in ochem 2 (for carbohydrates)

[@Leah4sciMCAT]

Fischer projections never go away! Thanks for watching! Hope the video helps.

[@wihagadilshan999]

Amazing explanation ## Love you

[@Leah4sciMCAT]

Thank you so much 🙂

[@saysHotdogs]

Am I stupid (orobably) or does that last Fischer projection with all the methyls not have any chiral carbons? If it does I am so lost. Just when I think I have a handle on this I see something that seems to defy what I’ve learned so far 😢

[@Leah4sciMCAT]

No, you're correct! This last slide of examples was an error in the video. You can see my note about the error in the video description: Note: @11:56 These would not be chiral carbons because the carbon is attached for three of the same side groups. Neither of the molecules that appear on the screen at 10:46 have chiral centers, as neither have carbon atoms that are surrounded by 4 unique substituents.

[@aleksandrakacperczyk3338]

How is it possible that this last molecule (12:20) has two chiral centers if it has the same substituents?

[@Leah4sciMCAT]

the methyls were just an example of 'something there' for the purpose of understanding the 3D but you're right, methyls would make it achiral

[@adamart3982]

Thanks a lot Sometimes you mention somethings that are not needed and just make the topic more confusing. For example, when you draw a methyl group down an amino acid, we don't need to hear (Alanine's R group), instead, you can just say an R group, or a methyl. Specially when you mention an "out of the topic" thing very fast, it becomes double confusing. Thanks

[@Leah4sciMCAT]

I appreciate you taking the time to share your feedback on my videos. My intention is to bring in supporting material rather than to confuse you with extra information. Since this video was recorded with MCAT students in mind, and they do have to know that alanine's R group is indeed a methyl, I don't consider that extraneous information. That being said, if you don't need to know those things, I challenge you to ignore them and only focus on the aspects you need in the hopes of better learning this information. (or just watch another video)

[@adamart3982]

I had a final exam and was very stressed meaning that I didn't want to hear something like amino acids while learning this complex topic of strong acidity and basic. Sorry for the inconvenience! But now it is over and there is no stress any more. . You can mix any topic with any topic, even you can talk about how high the Everest is with the topic of IUPAC namingclature, or just mix the topic of a Greek cheese is expensive with the topic of exothermic curves! @@Leah4sciMCAT

[@prashantpoudel9678]

if you were my teacher i could study org chem all day..

[@Leah4sciMCAT]

+Prashant Poudel you can study all day, I have over 200 videos on KZbin so far

[@rassimsimou1594]

Good

[@Leah4sciMCAT]

Thanks

[@alforex5105]

can you explain the book thing? please

[@Leah4sciMCAT]

Of course! Imagine that the molecule with chiral center C is a closed book lying on a table. The spine of the book would be the line from A to C to E. The front cover of the book would be D, and the back cover of the book would be B. To open the book, the front cover D would be swung towards us and to the left. Now we have both front cover D and back cover B coming towards us in a horizontal line, and the spine of the book is running in a vertical line between D and B. Now in reality, a book would lie on the flat plane of a table. In a Fischer projection, the horizontal line is projected out of the plane (towards us), and the vertical line is projected into the plane (away from us). The analogy is limited, but helps visualize the movement of the molecule into a Fischer format.

[@prashantpoudel9678]

thank yu again..

[@Leah4sciMCAT]

+Prashant Poudel you're welcome

[@rithikamedari1223]

11:56 These would not be chiral carbons because the carbon is attached for three of the same side groups

[@Leah4sciMCAT]

You are correct. Neither of the molecules that appear on the screen at 10:46 have chiral centers, as neither have carbon atoms that are surrounded by 4 unique substituents. Thanks for bringing it to my attention!

[@madrabbit9007]

Sweetlove you are saving my bacon in organic chem. If ever we meet I own you a drink.

[@Leah4sciMCAT]

I'm glad I was able to help! Can we make it chocolate instead? :)

[@madrabbit9007]

Lady's choice, too bad I am likely old enough to be your dad.

[@Leah4sciMCAT]

I'll still accept chocolate ;)

[@iSonikYT]

Great videos! thx alot :)

[@Leah4sciMCAT]

+iSonikYT you're very welcome

[@saramalik5440]

Book analogy is as confounding as it cud get... doesn’t make any sense

[@Leah4sciMCAT]

Thanks for your feedback, I appreciate it.

[@ashfaquealam1194]

+Leah4sciMCAT Can you please clear my doubt why at 7:00 (kzbin.info/www/bejne/sHKQgHSZoq2hiJom) you write 1 on NH3+ not at CO2-. Please anyone clear my doubt.

[@agent475816]

Nitrogen's atomic number is higher than carbon. Carbon is 6 and nitrogen is 7 so it gets higher priority right off the bat.

[@Leah4sciMCAT]

Using the Cahn-Ingold-Prelog system for ranking, Nitrogen outranks carbon making it the highest priority. I teach this in detail in my stereochemistry series here: leah4sci.com/chirality

[@hamzajaleel7082]

Man I cant do this shit 😢

[@Leah4sciMCAT]

I'm sorry to hear that it's giving you so much trouble. If you see you need more help, reach out at leah4sci.com/contact and let me know what type of help, specifically, you are looking for.

[@eobardrush2112]

Ah the whole book concept lost me

[@Leah4sciMCAT]

I’m sorry! The analogy doesn’t resonate with everyone and is limited in its comparison. You can imagine that the molecule with chiral center C is a closed book lying on a table. The spine of the book would be the line A-C-E. The front cover of the book would be D, and the back cover of the book would be B. To open the book, the front cover D would be swung towards us and to the left. Now we have both front cover D and back cover B coming towards us in a horizontal line, and the spine of the book (A-C-E) is running in a vertical line between D and B.

[@FAITHYNCHUKUNDAH]

you sound like selena gomzez

[@Leah4sciMCAT]

What a compliment, thank you!!!

[@user-kp9be7fr6p]

I will explain myself better. Your explanations in other subjects like elimination, reactions and so are the best that I ever saw. This specific video does not explain how to see Fischer projections and therefore unlike your other excellent videos this one is not so good.

[@Leah4sciMCAT]

Did you see the entire Fischer series? If yes then... don't know what to say.

[@Abaddonian]

I hate Emil Fischer and I'd rather just use the regular representation.

[@Leah4sciMCAT]

Fischer projections are actually quite useful for complex sugars

[@Abaddonian]

@Leah4sciMCAT sorry just screaming into the void to vent my frustrations over organic Chem. Lol

[@emandme5536]

You sound like Selena Gomez

[@Leah4sciMCAT]

I love her voice so thanks