Sawhorse to Fischer Projections + Shortcut (vid 3 of 5)
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- Опубліковано 5 лют 2025
- leah4sci.com/f... Presents: Converting Sawhorse to Fischer Projections and Fischers to Sawhorse + Shortcut
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This video (3 of 5) shows you how to convert a 3-dimensional sawhorse projection of a molecule to a 2-dimensional Fischer projection and back. Learn the proper tedious method + my shortcut.
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You explain everything so well!!! I wish I had a teacher like you! Thank you soo much for your efforts!! :)
You're very welcome!
ua-cam.com/video/OMRCzhaeTrE/v-deo.html
Oooommggg...No one on earth could have explained this 3d thing verbally In the way you did..My mind is blown away ❤️❤️❤️
Glad you like it!
The absolute best video I got to watch for this stuff! I wasn't able to do this for a lot of time now and this video is so goddamn helpful. Thanks so much, Leah!!!
Glad I could help :)
I don't know how to thank you... your explanation was great and you gave me great help...
Allah bless you
Your kind words are enough!
watched maybe 3-4 videos, but this was the most helpful. THANK YOU!
Wow, I'm so happy to hear that! Glad I could help!
Thanks every time I forget or unknown I watch your videos and get it❤
You're so very welcome, I'm happy to help!
Really love this online lectures.helps a lot..Thanks to contributors
You're welcome. Glad you like them
still really helpful in 2018! thanks you so much! now I am confident about the exam tomorrow!
Seeing this too late! How did your exam go?
Leah4sciMCAT LOL yea it's kinda too late but the video saved my exam since we had three questions that related to fischer projection. thanks again.
I'm glad it could help! I'll keep my fingers crossed for you as you await scores :)
You are the reason I understand anything about ochem. Thank you!
You're welcome!
Great effort! Thank you so much. Really helped me!
You're very welcome
hi, thanks for the video. i cant tell why you decide to specifically rotate one carbon 180 degrees over the other? for example in the last example you provided i got a different projection with F going into the page and Cl sticking out. How can i pick one of the two ?
My top middle structure in the last example at 13:30 is exactly as you described. F going into the page and Cl sticking out.
Really, when it comes to rotating the bond, you can move either chiral center to align with the other. Ultimately, we just need to look at the molecule from the right perspective before drawing the Fischer because we know the horizontal lines in a Fischer projection are coming out of the page by convention. That means we might have to look at the sawhorse from the underside of the molecule if that's where the F and Cl are both pointing.
I love your tutorials, I'm the hero in organic chemistry, keep up this good work
Thank you! Glad you love the videos. :)
At 2:25, are you referrring to the same molecule by '3d molecule' and 'molecule on the left'?
Yes, correct. The 3D molecule is the sawhorse projection on the left of the screen.
Thanks a lot for this video! it cleared up a lot of concepts, just a question: in the short cut you showed for converting a sawhorse to a fischer, what was the point of dividing the molecule into up and down with a line?
You're welcome! The point is that we want both of our non-carbon substituents on either chiral center to ultimately be on the top-side of the molecule. The carbon substituents will need to be on the bottom-side as they are the ones lined up along the backbone of the Fischer projection.
Ma'am you are op❤️..... nicely taught
Thanks a lot 😊
Do we look at the fishcer from right or left to convert ot sawhorse? Or does it have to always from left as you did in this video ?? Could you please help!
I'm a bit unsure of your question. In the example at 11:00, where I converted the Fischer projection to a Sawhorse, I chose to place the purple carbon on the right and the green carbon on the left. I could have chosen to place those two carbons on opposite sides of the Sawhorse, but it would have changed my perspective on the molecule. Meaning, the atoms in the back would now be drawn in the front, and vice versa.
For more help with questions like this, I recommend joining the MCAT Study Hall. For details, visit join.mcatstudyhall.com/ or contact me through my website leah4sci.com/contact/
omgggg amazing, thanks a lot
You're very welcome 😊
Thx from France
You're welcome
That was very helpful. ThankYou for posting this. My question here is, at 6:30 how do we choose which methyl is to be placed on the top n which on the bottom? And will that make any difference to the molecule?
I have the same question...
There are 2 ways of looking at this molecule. choose one direction then make sure you're consistent throughout
Much helpful for students preparing for JEE ...
mam plzz try to cover all organic syllabus 😅
Like this? leah4sci.com/syllabus
valeu professora.. ótima aula
Thank you!
Very very helpful. Thanks a lot.
+Adnan Kagzi you're welcome
+Leah4sciMCAT Can you also lead us to Geometrical isomerism in cyclic compounds
Hi, i went to your website and did the quiz but how do we access the answers ? I see a lot of comments of people asking the same thing ?
Hello! If you scroll to the bottom of the quiz, there is a red button that says "Send Me The Solutions!". If you click that and put in your email address, I will send you a PDF copy of the quiz solutions. For further questions, feel free to contact me through my website at Leah4sci.com/contact
Thank you teacher. It was really helpful.🙏🏼🙏🏼🙏🏼
You are welcome!
2023 and still helpful 🎉 thank you
So glad to hear this! You're very welcome.
you saved me. thank you
You are welcome!
@@Leah4sciMCAT I've watched a lot of your videos, and you always explain so clearly. thank you
Thank you!!! Still appreciating this !
you're welcome!
Once you translate everything into fischer does it matter if input my OH at the top left and Br at bottom right? I guess i just see it from another point of view
I'm sorry, but I don't offer tutoring through UA-cam comments. For help with this and more, I recommend joining the MCAT study hall: join.mcatstudyhall.com/
Thank you sooooooooo much for beautyful explanation.....Organic Chemistry is Beautyful one as like your explanation...Thank You soooooooo much...
You are so very welcome!
thank you so much ur vedoes are so helpfull but here's a quuestion : does which carbone i choose to put up matter : what if i chose the blue carbone do i have to imagine i'm looking from oposite side (right) so i will see the H from the blue carbon in my left and the bromine on my right
+arba mld it's a question of HOW you look at it. The molecule itself will retain its chirality and identity
Hi, I'm asked to do Fischer projection from a sawhorse that has no wedge or dash bonds, every bonds is just represented by a straight line, can you help? Thanks
The sawhorse projection must be drawn in a way that represents the molecule in three-dimensions. Wedge or dash bonds would be the primary method for showing the necessary conformational information. It’s possible that your sawhorse is drawn so that you are looking down a particular carbon-carbon bond, similar to looking at a Newman projection.
2:58 how to decide, which carbon to rotate?
When we talk about rotation, we're talking about rotating a carbon to carbon BOND. You could think of it as making the substituents on both carbons face in the same direction.
So it's really a matter of perspective. Do you want to draw your Fischer projection by looking at the molecule from below? Then, rotate so that the substituents on both carbons are facing down.
Or, do you want to draw your Fischer by looking at the molecule from above? Then, rotate so that the substituents on both carbons are facing up.
thank you! this was very helpful for me
You're welcome! Glad it helped!
Hello Leah! I really like your videos, they are great to watch! I have a question and I wonder if you could help me out!
The thing is: What if in the Sawhorse-projection, the substitutes don't have an indicator wether they're going in or out of the paper, how do I know which atoms will be "on the side" of the fisher-projection and which will be facing down in it? Help would be much appreciated!
+DrReagge If the molecule is achiral then it doesn't matter. If it's chiral but not shown you can draw both enantiomers
Thank you so much!!!
You're welcome!
very well understood through ur vedio
Glad you understood!
Hey Leah you mentioned in a previous video that the horizontal lines of a Fisher projection represent wedges or molecules going into the page. Yet here, in your first example the hyrdrogens that were on dashes (coming out of the page) ended up on the horizontal lines of the Fisher. So I am a bit confused, do the horizontal lines of a Fisher represent dashes or wedges?
Abid Karmali wedges
To clarify, horizontal refers to wedges coming OUT of the page, and vertical refers to dashes going into the page
Wow, thanks, Leah!!!!!!! : )
You're so welcome!
Thank you soooo sooo soooo much!
You're welcome!
Thank you sooo much mam . I found it very useful:-)
You're very welcome!
hi we need change the br to wedges n h to bold?
I'm not following your question. Is this about the video? If so, at what specific point?
why we have to rotate to get fisher projection (you rotate -Br from out of page to inside of page) I dont understand that part
+Yixi Dong watch the Fischer intro video which explains the precise orientation requirements
i can`t find the video ?
a very helpfull exolanation thank you , but like no one have noticed that her voice is similar to celina gomez's ?
I'll take that as a compliment! Thanks!
Thanks it's so helpful
+محمد مصطفى you're welcome
nice teaching concept of projection
Glad you enjoyed it!
Thanks so much !
You're welcome!
Thank you Leah😊
But I found this after my exam😭
I'm sorry you didn't have it in time; fingers crossed the exam turned out ok for you!
thank you.
You are very welcome!
thank you!
+Brenda Lim you're welcome
I don't understand why when the 180° turn was made the oh and the h stayed the same if you said sad everything turns the opposite way
Thanks for asking. I don’t believe I said that everything turns the opposite way. At 2:42, I explained that we need to rotate the bond between the blue and green chiral carbons by 180 degrees, so that the substituents are facing in the same direction. That means keeping the blue end of the molecule in the same position (OH and H stay the same), while rotating the green end of the molecule to face in the same direction as the OH and H.
Thanks A Lot For Clearing My Concepts.
You are so welcome.
at 10:51 cl and h seem to be on the left
im looking at it as if my head was above the purple carbon.. cl is on my left
There are many ways to look at a Fischer projection. Please follow along with the video to see and understand how I'm looking at it. Once you get my method use it to craft the method that works best for you
Can you help me assignment
For tutoring inquiries, email me here: leah4sci.com/contact
you didn't explain why the OH stays in the same position :(
In this particular sawhorse projection, the substituents on the blue carbon (the OH group included) are already sticking up. No further rotation is needed to place it on a Fischer projection where the horizontal lines are, by convention, sticking out of the page. Thanks for watching and asking!
❤❤❤❤
thank you!
thank you for the explanation but that is not a sawhorse projection thats a line diagram projection
Thanks for pointing this out
Excellent
thanks so much!
thanks from pakistan
You're welcome
Love you mammmm
Thanks!
How to convert sawhorse when hydrogen is not in backward
I'm sorry, I don't offer tutoring over UA-cam comments. For help with this and more, I recommend joining the MCAT study hall. Full details: join.mcatstudyhall.com
I don't think this method works; the chiral centers changed configuration once she converted the molecule into a fisher projection. I thought we were supposed to maintain the configuration.
The chiral centers do NOT change R/S configuration when the central carbon-carbon bond in the molecule is rotated. Chiral configuration remains constant using this method for both examples in the video.
very very confusing.. : (
+dinesh ranawat sorry you found it confusing. Which aspect did you find confusing?
+Leah4sciMCAT nothing Leah ......when I watched this video agin I understood everything...... thank u for helping me.......God bless you... :-)
Your method is confusing.
Sorry to hear that I confused you. What was confusing about it?
Thank you!
You're welcome!