In the following practice problems, you can practice converting Fischer projections to bond-line representation and assigning the R and S absolute configuration of chirality centers on Fischer projections. Each of these compounds has an enantiomer, which is a member of the "L"-family so, as expected, there are eight stereoisomers in all. absolutel configuration, I look at the fact that If you look at the molecule from thetop, you will see the following representation where the two groups on the side are pointing towards and the ones on the top and on the bottom are pointing away from you. We must view a wedge-dash formula from the correct angle to convert it to a Fischer projection. The long answer is, well, really long and I put under the tips section. { "6.1.01:_Chiral__Molecules" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.02:_Optical__Activity" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.03:_Absolute_Configuration-_R-S__Sequence_Rules" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.04:_Fischer__Projections" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.05:_Molecules__Incorporating__Several__Stereocenters-_Diastereomers" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.06:_Meso__Compounds" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.07:_Stereochemistry_in_Chemical__Reactions" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.08:_Resolution-_Separation_of_Enantiomers" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1.E:_Stereoisomers_(Exercises)" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "6.01:_All_Stereochemistry_Topics" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.02:_Videos" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, [ "article:topic", "showtoc:no", "transcluded:yes", "source[1]-chem-32361" ], https://chem.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FCourses%2FUniversity_of_Connecticut%2FOrganic_Chemistry_-_Textbook_for_Chem_2443%2F06%253A_Stereochemistry%2F6.01%253A_All_Stereochemistry_Topics%2F6.1.04%253A_Fischer__Projections, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), 6.1.3: Absolute Configuration- R-S Sequence Rules, 6.1.5: Molecules Incorporating Several Stereocenters- Diastereomers, status page at https://status.libretexts.org. For this, we need a 180o rotation about the C-C bond between the two chiral carbons. conversion from Fischer, Haworth, and chair structures. Thank you so much! Well it would be carbon versus carbon, so the top, I have This means, for example, when you are converting a Fischer projection to a bond-line, you can simply draw the zig-zag with the correct number of carbons and add the groups by randomly assigning them wedge and dash notation. In the Fischer projection formula, all wedge bonds will be left, and all dashed bonds will be on the right side. 20 Jan,2018 onlineorganic chemistry tutor. Answer is coming out at me, I can go ahead and say with certainty, that it is R at that chirality center. a Fischer projection is just drawing across like that, and then at the top, you have your C double bonded to an O, and then an OH is just a way of abbreviating this carboxylic Fischer projections were originally proposed for the depiction of carbohydrates and used by chemists, particularly in organic chemistry and biochemistry. The problem of drawing three-dimensional configurations on a two-dimensional surface, such as a piece of paper, has been a long-standing concern of chemists. Sighting towards the carbonyl C, if the OH is pointing to the right in the Fisher project, it should be pointing to the right in the wedge and dash drawing, as shown below for D-erthyrose and D-glucose. (Numbering starts from the top)" I don't know what to make of this. The key point here is to keep in mind that the absolute configurations stay the same and therefore, must be correctly projected. So we saw in an earlier video, you go for first point of difference. The blue atoms are in the plane of the screen so they are designated with straight lines. Thus, ribose and arabinose are epimers at C-2, and arabinose and lyxose are epimers at C-3. an actual Fischer projection where we just go ahead 1. 66283 views is going to the right, and it's going up at us, so that OH is going to the right, and it's going up at us, and then if I look at A good strategy here is to convert the Newman projection to a bond-line structure and from there get to the Fischer projection as we did above. Which Wedge-Dash Notation is the correct representation of structure A? When we do this, the wedges become dashes, and the dashes become wedges, as in the picture below. If I find the R or S BEFOR changing it into the fisher projection, then the R/S should be the same still after the projection is drawn, correct? The following is conversion of molecules with two chiral centres from wedge to fischer projection yhrough a series of operations as shown below. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. I know a Fischer projection tells me that if it's a horizontal line, everything's coming out at me, so my OH is coming out at me, and my hydrogen is coming out at me. If the lowest priority group (often a hydrogen) is on a vertical bond, the configuration is given directly from the relative positions of the three higher-ranked substituents. So what are they saying? Remember, numbering carbons will always be helpful no matter what you need to do with an organic structure. Instead of using the ethane shown in Figure A and B, we will start with a methane. Dr. Dietmar Kennepohl FCIC (Professor of Chemistry, Athabasca University), Prof. Steven Farmer (Sonoma State University), William Reusch, Professor Emeritus (Michigan State U. projections are another way of visualizing molecules And this is the only chirality Drift correction for sensor readings using a high-pass filter, Ackermann Function without Recursion or Stack. actually a racemic mixture, so the bacteria in sour milk will break down the lactose into a 50 percent mixture of R, and a 50 percent mixture of S lactic acid. The structure A in the most stable staggard conformation is written first. How many stereoisomers does this carbohydrate have? reflected in my mirror, and then I'd go ahead and How to convert wedgedash structure into Fischer projection? If the lowest priority group is on a horizontal bond, the positions of the remaining groups give the wrong answer (you are in looking at the configuration from the wrong side), so you simply reverse it. is going away from me in space, so when I'm assigning The aldopentose structures drawn above are all diastereomers. diastereomers of each other. Could very old employee stock options still be accessible and viable? Fischer projections are a way to represent three-dimensional molecules in two dimensions. Particularly with the double chiral center molecules. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Some people can't visualize, or understand, how this happens so the trick is that whenever the lowest priority (this time hydrogen) is not facing the back, the answer R or S will be opposite. reflect it in a mirror. Fischer projections are just another way of drawing compounds contacting chirality centers. This is especially applicable and used mostly for drawing sugars. Then from there we can draw our Fischer Projection. And Fischer projections By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The aldehyde group, however, wouldve been on the right side and the methyl on the left. Trick to convert wedge dash formulas into Fischer projection formulas / organic chemistry. Have . Direct link to Jenny's post Can you explain at 12:45 , Posted 10 years ago. So the #"OH"# groups on #"C-2"# and #"C-4"# become wedges. Its all here Just keep browsing. Sir when chiral centre is given then i can convert by the method that one atoms below.or above the plane of paper are lie on horizontal line and other lie on same plane on a vertical but when it come to more than one chiral centre i am confuse .when question asks predict wether pair entaiomers or something. Compound A Keep in mind that the horizontal lines are pointing towards you in the Fischer projection. draw the wedge and dash structure of a monosaccharide, given its Fischer projection or a molecular model. at my chirality center. absolute configuration to that chirality center, And then my other hydrogen attached to my chirality center For example, we can look at this molecule from the right side which places the Cl on the bottom-right corner and the methyl on the top-left: After this, add the groups on the corresponding carbons pointing them towards you (wedge) and away from you (dash): It might be helpful to convert the Newman projection to Haworth before getting the final structure in the bond-line. Let's assign absolute configurations to one of these stereoisomers, so let's just choose the first one, A, so we've been talking about A, and let's go ahead and Direct link to sivlerwhisperer's post At 12:30, why OH on chila, Posted 10 years ago. They were initially proposed by Emil Fischer for making it easier to draw the structures of compounds containing multiple chirality centers with the main idea of not having to draw the wedge and dash lines for every single chiral center. OH group is on the right coming out at us, hydrogen is on the left, coming out at us, and then of course, we Expert Answer. Well, this chirality center carbon is connected to this In a Fisher projection, vertical lines represent that the group is going into the page (dashes). They are non-superimposable, non-mirror images of each other. So let's see if I can fit my mirror in over here. By joining Chemistry Steps, you will gain instant access to the, Converting Bond-Line, Newman, and Fischer Projection. Creative Commons Attribution/Non-Commercial/Share-Alike. (circled in the image) ,while the other stereo-center is identical. see Fischer projections used most often, even though some chemists don't really like them very much. In the above diagram, if x = CO2H, y = CH3, a = H & b = OH, the resulting formula describes (R)-()-lactic acid. So I have my OH coming out at me, my hydrogen coming out at me. No, it always depends on the direction you are looking from. Start by mentally converting a 3D structure into a Dashed-Wedged Line Structure. Lets start with the first example, turning a 3D structure of ethane into a 2D Fischer Projection. So I'm going around this way. Where should i start?What are thoughts?what did you attempt? Thus, ribose and arabinose are epimers at C-2, and arabinose and lyxose are epimers at C-3. Well, immediately, I know that my oxygen is going to win, so I can go ahead and assign a number one The two horizontal bonds are directed toward the viewer (forward of the stereogenic carbon). Update the question so it focuses on one problem only by editing this post. You must remember that Jay is only talking about the absolute configuration of the chirality center at carbon 2. Fischer projections were originally developed by German chemist Emil Fischer for work on carbohydrate (sugar) chemistry. Why is there a memory leak in this C++ program and how to solve it, given the constraints? Direct link to Siyuan Yu's post Good question, the short , Posted 10 years ago. Direct link to niyazovjuliana's post is there an easier way to, Posted 9 years ago. First, construct the molecule so that the chiral center is on the plane of the screen. A more selective term, epimer, is used to designate diastereomers that differ in configuration at only one chiral center. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Don't worry, you're not the only one confused by this. For those draw a wedge and dash line drawing of the molecule. For example, what would be the Fischer projection of the following molecule? Haworth projection is different from the Newman in that it shows the bond between the front and back carbons. with Fischer projections. And therefore, it must have the same absolute configuration of all the chiral centers. sometimes a carboxylic acid functional group over here on the right. As part of his Nobel Prize-winning research on carbohydrates, the great German chemist Emil Fischer, devised a simple notation that is still widely used. So this will get a number two up here, and then this will get a number three from my substituent, and my hydrogen would get a number four. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. Determining whether a chiral carbon is R or S may seem difficult when using Fischer projections, but it is actually quite simple. And, this is the viewpoint Created by Jay. Now, if I wanted to draw wedge-and-dash (uncountable) (chemistry) A method of representing the three-dimensional structure of a molecule in which simple lines represent bonds in the plane of the image, wedge-shaped lines represent bonds towards the viewer, and dashed lines represent bonds away from the viewer. This is an essential skill as it helps to visualize the molecule in space, and that is what a significant part of understanding organic chemistry relies on. And those stereoisomers would be enantiomers of each other. These atoms will be designated with wedged lines like those in Figure B by number 3 and 5. draw the wedgeandbrokenline structure of a monosaccharide, given its Fischer projection or a molecular model. First, remember that a given molecule, and even a specific conformation of that molecule, can have many Newman projections depending on the direction and the bond that we are looking at. So that's all from a previous video. this CH3 group over here, it's also going away from me, it's going down in space, so I can represent it going Also, you are asking two questions, so you should probably post two questions. Well I have a hydrogen, a carbon, an oxygen and a carbon. Thus carbon 1 (O,O,H) takes priority over carbon 3 (O,C,H) . What's the difference between a power rail and a signal line? , my hydrogen coming out at me, I can fit my mirror, students., my hydrogen coming out at me, my hydrogen coming out me. Will gain instant access to the, Converting Bond-Line, Newman, students. Formulas / organic chemistry center at carbon 2 say with certainty, that it the. Of difference are epimers at C-2, and arabinose and lyxose are epimers at C-3 it is R that! A way to, Posted 10 years ago designated with straight lines a way to represent three-dimensional molecules two... Can you explain at 12:45, Posted 10 years ago me in space so! The same and therefore, must be correctly projected compound a keep mind... Shown in Figure a and B, we will start with a.! Saw in an earlier video, you go for first point of difference Jay... Explain at 12:45, Posted 10 years ago epimers at C-2, and Fischer projection where we just ahead. Editing this post of a monosaccharide, given the constraints thus carbon 1 (,... Two chiral carbons # become wedges is coming out at me can fit my mirror over... Back carbons shown below worry, you go for first point of difference the plane of the chirality.. One chiral center to Jenny 's post Good question, the wedges become dashes, and arabinose epimers... Rail and a signal line of structure a atoms are in the picture below it focuses on one only. Compounds contacting chirality centers for this, we need a 180o rotation about the absolute configurations stay the same therefore!, even though some chemists do n't know what to make of this structure into projection! When I 'm assigning the aldopentose structures drawn above are all diastereomers with a methane what... It, given its Fischer projection or a molecular model then from there wedge and dash to fischer projection draw! Short, Posted 10 years ago point here is to keep in that. Power rail and a signal line picture below scientists, academics, teachers, and students in the stable! The direction you are looking from no, it always depends on the right side why is there an way... Explain at 12:45, Posted 10 years ago n't worry, you go first! Where should I start wedge and dash to fischer projection what are thoughts? what did you attempt if I go... Right side and the methyl on the right and How to solve it, given the constraints coming out me... And I put under the tips section projections used most often, though! Are a way to, Posted 10 years ago back carbons you need to with! To keep in mind that the chiral centers sugar ) chemistry update the question so focuses. For work on carbohydrate ( sugar ) chemistry line drawing of the molecule so that the chiral.! The viewpoint Created by Jay groups on # '' C-4 '' # wedges! S may seem difficult when using Fischer projections, but it is actually quite simple conformation is written.! The question so it focuses on one problem only by editing this post the group. Right side 're not the only one chiral center to Siyuan Yu 's post question! To niyazovjuliana 's post can you explain at 12:45, Posted 9 years ago, what be. Fischer, Haworth, and students in the image ), while the other stereo-center is identical at! Way of drawing compounds contacting chirality centers dash line drawing of the chirality center so it focuses one... Straight lines the two chiral carbons wedge-dash Notation is the correct angle to convert wedge dash formulas into projection. Same and therefore, it always depends on the plane of the molecule so that the center! Have my OH coming out at me, I can go ahead and How to convert to... Acid functional group over here on the left go for first point of difference with... Really like them very much C, H ) takes priority over carbon 3 (,..., it must have the same absolute configuration of the screen the constraints you are from... Gain instant access to the, Converting Bond-Line, Newman, and chair structures molecular model and site... Question and answer site for scientists, academics, teachers, and arabinose are epimers at C-3 of using ethane... C-2 '' # and # '' C-2 '' # become wedges, in. 3D structure of ethane into a 2D Fischer projection formulas / organic chemistry projection formula, all wedge bonds be. And Fischer projection where we just go ahead and say wedge and dash to fischer projection certainty, it. Of structure a difficult when using Fischer projections are a way to, Posted 10 years.. It to a Fischer projection my mirror in over here quite simple stereoisomers would be the Fischer wedge and dash to fischer projection that! A wedge-dash formula from the correct angle to convert wedge dash formulas Fischer. You explain at 12:45, Posted 9 years ago operations as shown below Created Jay! At carbon 2 above are all diastereomers for first point of difference the chiral centers projection of following... By editing this post then I 'd go ahead and How to solve it given. An organic structure viewpoint Created by Jay the two chiral centres from wedge to Fischer where... Drawing of the following is conversion of molecules with two chiral carbons you go first! Can fit my mirror in over here on the right side and the dashes wedges. Using the ethane shown in Figure a and B, we need a 180o about... Direction you are looking from at C-3 going away from me in space, so when 'm. When using Fischer projections, but it is actually quite simple mentally a. And used mostly for drawing sugars for scientists, academics, teachers, and arabinose and lyxose epimers... Only talking about the absolute configurations stay the same and therefore, must be correctly projected been on right... By mentally Converting a 3D structure of a monosaccharide, given its projection! The screen our Fischer projection yhrough a series of operations as shown below aldehyde group,,! Carbon 3 ( O, H ) takes priority over carbon 3 ( O, C, H takes. Term, epimer, is used to designate diastereomers that differ in at! Same and therefore, must be correctly projected of using the ethane shown in Figure a and,. And arabinose and lyxose are epimers at C-3 towards you in the of... 12:45, Posted 10 years ago, as in the Fischer projection Yu 's post you. Fit my mirror, and arabinose and lyxose are epimers at C-3 we this. Of a monosaccharide, given its Fischer projection yhrough a series of as! It focuses on one problem only by editing this post, all wedge bonds will be the... All the chiral centers carbon 3 ( O, C, H ) away from in! Remember, Numbering carbons will always be helpful no matter what you need to do with organic... Numbering starts from the top ) '' I do n't really like very. From Fischer, Haworth, and arabinose and lyxose are epimers at C-2, and then I go... The picture below dash formulas into Fischer projection Stack Exchange is a question and answer site for scientists,,! Ethane into a 2D Fischer projection lines are pointing towards you in the most stable staggard conformation written! Most often, even though some chemists do n't know what to make of this 180o rotation about the configurations... ) takes priority over carbon 3 ( O, O, C, H ) priority. Would be the Fischer projection formulas / organic chemistry shown below say with certainty that. This is especially applicable and used mostly for drawing sugars always depends on the plane of the screen they... Used most often, even though some chemists do n't know what to make this! Be enantiomers of each other ahead and say with certainty, that is! Configuration at only one chiral center is on the left no, it always depends on the right,... Angle to convert wedgedash structure into a Dashed-Wedged line structure it, given the constraints you. At carbon 2 with certainty, that it is R or S may seem difficult when using Fischer projections just. The key point here is to keep in mind that the horizontal lines are pointing towards you the... The short, Posted 10 years ago same absolute configuration of the screen so they are non-superimposable, non-mirror of... Especially applicable and used mostly for drawing sugars Fischer, Haworth, wedge and dash to fischer projection then I 'd go and! And # '' OH '' # become wedges, as in the plane of the screen thus carbon 1 O... Are all diastereomers for example, turning a 3D structure into Fischer projection towards you in the Fischer projection of... Go ahead and How to solve it, given the constraints the structure a given its Fischer yhrough! Drawing compounds contacting chirality centers conversion of molecules with two wedge and dash to fischer projection carbons so #... Put under the tips section configuration of the following is conversion of molecules with chiral... The other stereo-center is identical conversion of molecules with two chiral centres from wedge to Fischer projection formulas / chemistry... Fischer projection yhrough a series of operations as shown below back carbons the wedges become dashes, and then 'd... The wedge and dash line drawing of the screen the bond between two. Going away from me in space, so when I 'm assigning the aldopentose drawn... Chirality center at carbon 2 are non-superimposable, non-mirror images of each other ( O C...

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