Determine if carbon #2 in D-glucose is R or S. Organic Chemistry 1 and 2Summary SheetsAce your Exam. the carbon on the right is double bonded to an oxygen, so that's gonna give it higher priority than the carbon over here on the left, since that's bonded to hydrogens. The stereochemical formula for (R)-lactic acid can be drawn using the wedge-dashed structure and Fischer projection method. These eight stereoisomers consist of four sets of enantiomers. How can I convert S-1-fluoro-2-chloropropane to a Fisher projection? Now that we have our Dashed- Wedged Line Structure, we can convert it to a Fischer Projection. Direct link to Jenny's post Can you explain at 12:45 , Posted 10 years ago. When you flatten the structure onto the surface of the cylinder, you get the Fischer projection of D-glucose. Well, that's oxygen versus carbon, versus a carbon over here in my carbonyl, so obviously oxygen's going to win, so we can assign oxygen draw the wedge and dash structure of a monosaccharide, given its Fischer projection or a molecular model. Well, if I'm staring down this way, I could draw a line right here to represent my flat sheet of paper, and I can see that both my hydrogen and my OH are above my sheet of paper, whereas my carboxylic acid and my CH3 are below my sheet of paper. Direct link to Tim's post Excellent question, Luke., Posted 10 years ago. I'm gonna stare down, Since there are three chiral centers in this constitution, we should expect a maximum of 23 stereoisomers. I have my OHs on the right, I have my hydrogens, I have my CHO, I have my CH2OH. This will put the CN and Br groups as wedge lines, the OH and Cl as dash lines. In this instance, he is trying to assign priority based on the what carbons 1 and 3 are bonded to, not the rest of the molecule. in the diastereomer video, if I took one of the ones from A and B, so let me just go ahead and circle that. Since the vertical bonds extend away from the viewer and the horizontal bonds toward the viewer, a Fischer structure may only be turned by 180 within the plane, thus maintaining this relationship. How to draw Fischer projections for carbon chain having more than two carbons? Notice the red balls (atoms) in Figure A above are pointed away from the screen. Trick to convert wedge dash formulas into Fischer projection formulas / organic chemistry. Direct link to Luke Bauer's post My question is how do you, Posted 10 years ago. And let's see how can we figure out the absolute configuration at my chirality centers for my Fischer projection. So it just makes it a little bit tricker than usual, so here I acid functional group, and then I have a hydrogen over here, and then I have an OH group over here, and then I have a CH3 here, so this is a Fischer projection, this is the Fischer Draw 'zigzag' structures (using the solid/dash wedge convention to show stereochemistry) for the four sugars in the figure below. I am going around this way Well I have a hydrogen, a carbon, an oxygen and a carbon. And now we need to convert this into the more stable staggered conformation shown in zig-zag. So I would stare down Worked Example \(\PageIndex{1}\) You must remember that Jay is only talking about the absolute configuration of the chirality center at carbon 2. The Fischer Projection consists of both horizontal and vertical lines, where the horizontal lines represent the atoms that are pointed toward the viewer while the vertical line represents atoms that are pointed away from the viewer. Figure C Figure D. Lets start with this 3D image and work our way to a dashed-wedged image. Can the Spiritual Weapon spell be used as cover? The two horizontal bonds are directed toward the viewer (forward of the stereogenic carbon). Lets start with the first example, turning a 3D structure of ethane into a 2D Fischer Projection. Identify all the chiral centers in each Fischer projectionand determine the absolute configuration as R or S: Some more practice example of the Fischer projection. Have . Our hydrogen is on the left coming out at us so let's go ahead and put those in. In a Fischer projection, the carbon atoms of a sugar molecule are connected vertically by solid lines, while carbon-oxygen and carbon-hydrogen bonds are shown horizontally. 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. different stereoisomers for this molecule, we'll draw them in a few minutes. Could you edit your question and give an example that you attempted? How can I convert R-2-bromopentane to a Fisher projection? The reason being is that it allows us to only focus on one central carbon, which make things a little bit easier. possible stereoisomers for this carbohydrate. If we are viewing from above, we must mentally rotate the bonds so that C-2 and C-4 are pointing "up". Many times when I work problems that turn one dimensional double chiral centered molecules into fisher projections, I follow the correct path of lining the carbons down the projection but cannot seem to end up with the right side placements. How do you draw Fischer projections of carbohydrates? and draw straight lines, and the intersection The use of Fischer projections in non-carbohydrates is discouraged, as such drawings are ambiguous and easily confused with other types of drawing. it's going around clockwise, therefore this is the R And this carbon is bonded to an oxygen and a carbon, so what is the absolute configuration of this carbon here. These atoms will be designated with wedged lines like those in Figure B by number 3 and 5. The two vertical bonds are directed behind the central carbon (away from the viewer). Who are the experts? Direct link to Ricky Gandhi's post At 11:21, Jay said the CH, Posted 10 years ago. Well, you can remember that Fischer projections like you and they are coming to give you a hug with open arms: Or, you look at the Fischer projection like you are in the gym and need to grab the molecule. Planned Maintenance scheduled March 2nd, 2023 at 01:00 AM UTC (March 1st, We've added a "Necessary cookies only" option to the cookie consent popup. Regardless of the molecule shown in bond-line, Newman, or Fischer projection, it is still the same molecule! How does a fan in a turbofan engine suck air in? Where should i start?What are thoughts?what did you attempt? a) Draw Fischer projections of all the possible stereoisomers (with their mirror images) of the molecule 3,4-dibromo-2-chloro-2-methylpentane. I know the carbon is double bonded to an oxygen so I'm gonna go ahead and do that, that was that trick we learned in an earlier video for assigning absolute configuration. enantiomer to the stereoisomer that I just drew. draw the Fischer projection of a monosaccharide, given its wedge and dash structure or a molecular model. And this is the only chirality Below are three representations of the open chain form of D-glucose: in the conventional Fischer projection, a wedge/dash version of a Fischer projection, and finally in the 'zigzag' style that is preferred by many organic chemists. And the IUPAC numbering may not start from the top after it is rotated too. How many dipeptides are possible by the reaction of glycine and alanine? So that's all from a previous video. Over here, I picked one b) Label all stereocenters as R or S. c) Indicate any pair of enantiomers, diastereomers and the meso compound if present. subsituents attached to it, so with only one chirality center, we would expect to have two stereoisomers for this molecule. In the example below, we made the wedges on the around the world, Newman and Fischer Conformational Analysis. After completing this section, you should be able to. molecule in the mirror, and I would have the enantiomer, so this would be the By joining Chemistry Steps, you will gain instant access to the answers and solutions for all the Practice Problems including over 20 hours of problem-solving videos, Multiple-Choice Quizzes, Puzzles, and the powerful set of Organic Chemistry 1 and 2 Summary Study Guides. have this CH2 OH down here, is going away from us in space, so we go ahead and draw that CH2 OH going away from us in space like that. OH group is on the right coming out at us, hydrogen is on the left, coming out at us, and then of course, we Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Label all stereocenters R or S. 25.3: Depicting Carbohydrate Stereochemistry - Fischer Projections is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Steven Farmer, Dietmar Kennepohl, William Reusch, Henry Jakubowski, & Henry Jakubowski. So the #"OH"# groups on #"C-2"# and #"C-4"# become wedges. Lets start with a more simpler example. So this is one possible stereoisomer. Fischer projections were originally developed by German chemist Emil Fischer for work on carbohydrate (sugar) chemistry. of a Fischer projection, so if I'm going to convert this into a Fischer projection, When determining R or S, the lowest priority substituent needs to be facing towards the back, which can be done "turning" the molecule at the chirality center that the hydrogen is attached too. Well, you can remember that Fischer projections like you and they are coming to give you a hug with open arms: Or, you look at the Fischer projection like you are in the gym and need to grab the molecule. Fischer projections are useful when looking at many different diastereomeric sugar structures, because the eye can quickly pick out stereochemical differences according to whether a hydroxyl group is on the left or right side of the structure. After this, you need to simply show all the bonds with plane solid lines,keeping in mindthat thehorizontal groups are pointing towards youand the ones on thevertical line are pointing away from you: How do you remember which ones are pointing towards you? 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. How can I convert 3S,4R-dibromoheptane to a Fisher projection? Creative Commons Attribution/Non-Commercial/Share-Alike. Black wedges represent chemical bonds coming toward you, while dashed lines are for bonds that extend back behind the surface .We must view a wedge-dash formula from the correct angle to convert it to a Fischer projection. molecule in a mirror. Identify all the chiral centers and determine the absolute configuration asRorS: What is the relationship between these two structures? For going from Newman to the wedge-dash: imagine a horizontal line running through the center of the Newman projection; substituents above the horizontal line will all point upwards while those below the line will point downwards. The wedge and dash notations we have been using are effective, but can be troublesome when applied to compounds having many chiral centers. right here, this time. What is the relationship between these two structures? So I could just do this. oxygen versus carbon, and oxygen wins. And therefore, it must have the same absolute configuration of all the chiral centers. Fischer Projections allow us to represent 3D molecular structures in a 2D environment without changing their properties and/or structural integrity. 66283 views three to get our total of four on here. The point of intersection between the horizontal and vertical lines represents the central carbon. The best answers are voted up and rise to the top, Not the answer you're looking for? These atoms will be designated with wedged lines like those in Figure B by number 3 and 5. However, before we can convert this Dashed-Wedged Line Structure into a Fischer Projection, we must first convert it to a flat Dashed-Wedged Line Structure. And this aldehyde functional group, this CHO, you can see, is going down. down in space like that. The green balls (atoms) are pointed toward the screen. The reason for this is the fact that the absolute configuration of the chirality centers must be retained since it is the same molecule. So I'm going around this way. Instead of using the ethane shown in Figure A and B, we will start with a methane. is going away from me in space, so when I'm assigning Thus carbon 1 (O,O,H) takes priority over carbon 3 (O,C,H) . By joining Chemistry Steps, you will gain instant access to the answers and solutions for all the Practice Problems including over 20 hours of problem-solving videos, Multiple-Choice Quizzes, Puzzles, and the powerful set of Organic Chemistry 1 and 2 Summary Study Guides. 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. 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. Diastereomers are stereoisomers that are not mirror images of one another and are non-superimposable on one another.$\ce{^1}$, Enantiomers are chiral molecules that are mirror images of one another. Please also explain how to convert more than one chiral compound with wedgedash structure to Fischer projection. 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. What are wedges examples? 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. Is there a way to only permit open-source mods for my video game to stop plagiarism or at least enforce proper attribution? 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.