Explain which conformation you would expect to have the higher energy. Nov 03, 2017 conversion of wedgedash and newmann to fisher by vkp sir. View notes discussion12 from chem 232 at university of illinois, urbana champaign. The mirror image of a fischer projection representing rlactic acid represents slactic acid and vice versa, implying that twelve of the 24 fischer projections represent rlactic acid and the other twelve slactic acid. The newman projection is viewed on a line from the front carbon to the back carbon. For this case, we will line up the 2 and 3 carbon as labeled on the above image. Draw out the staggered newman projection of chloroethane. Fischer projection practice problem set with solutions. Fy bsc usch102 semester i paper ii stereochemistry i. In this topic, we will be discussing the interconversions of sawhorse projection formula into newman projection form followed by fischer form. Lesson 12 conformers select the newman projection that corresponds to the sawhorse projection shown. Redraw the given sawhorse projection such that it has an eclipsed conformation. Optical activity in the absence of chiral carbon biphenyls, allenes and spiranes.
This document is highly rated by class 12 students and has been viewed 361 times. Stereoisomers a newman projection is used to represent or visualize conformations of carboncarbon bonds within a molecule. How to easily convert a fischer projection into a haworth. If youre behind a web filter, please make sure that the domains.
First let me show you how to convert fischer projection to newman projection. Conversion of fischer projection into sawhorse and newman formula. Sign up now to enroll in courses, follow best educators, interact with the community and track your progress. Stereospecific and stereoselective synthesis with suitable examples, asymmetric. In the next post, well look at the fischer projection. May 25, 2017 condensed, expanded, line drawing, newman projections, fischer projectionsgeez whats the deal here, ochem whisperer.
This video 3 of 5 shows you how to convert a 3dimensional sawhorse projection of a molecule to a 2dimensional fischer projection and back. Nov 29, 2015 well, first lets construct a regular molecule, and then proceed to its sawhorse projection, and from there draw out its fischer projection. Conversion of fischer into sawhorse and newman projection formula. Discussion12 lesson 12 conformers select the newman. Use newman projections to draw the eclipsed and staggered conformations of chloroethane. Sawhorse projections are very similar to newman projections, but are used more often because the carboncarbon bond that is compressed in a newman projection is fully drawn out in a sawhorse projection. If the given sawhorse projection is staggered, it can be. Iupac has defined a zigzag projection as a stereochemical projection for an acyclic molecule or portion of a molecule where the main chain is represented by azigzag line in the plane. Jul 25, 2015 below is the written transcript of my youtube tutorial video converting sawhorse to fischer projections if you prefer to watch it, see video here, or catch the entire fischer projections tutorial series.
Eclipsed and staggered conformations are interconverted by rotation of 60 along the central cc bond. Sawhorse projections sawhorse projections are very similar to newman projections, but are used more often because the carboncarbon bond that is compressed in a newman projection is fully drawn out in a sawhorse projection. The easiest way to do this is to proceed via sawhorse projection if you are aware of that. Pdf interconversion of fischer and zigzag projections. Fischer projections are convenient for comparing the stereochemistries of molecules that have many chiral centers. The conformation of d2 symmetry passed through in the interconversion of two. In newman projection formula, the front carbon is represented by a dot and the back carbon by a circle encircling the dot. What i want to do in this video is show that you can really visualize longer chains, or even, well see in future videos, even cyclical, ringbased carbon molecules with newman projections as well. In this lesson, you will learn how to convert any of the sawhorse representation into newmann with the help of examples. Class 12 notes edurev is made by best teachers of class 12. Thus, the maximum number of fischer projections that can be drawn to represent rlactic acid is twelve. Stereospecific and stereoselective synthesis with suitable examples, asymmetric synthesis crams rule. Chirality due to helical shape, planar chirality cyclophanes, ansa compounds and trans cyclooctene.
Use hands or model atoms to help you see these configurations whenever the low priority group is facing towards you the wrong way. Newman,sawhorse to fischer projectioniitjeeneet concepts. How to convert newmann projections to fisher projections pls. Conversion of fischer into sawhorse and newman projection.
How to interconvert fischer projections while maintaining the configuration. Redraw each structure in a sawhorse projection of a stable conformation. Sep 19, 2015 sawhorse projections are the normal line structure molecules drawn usually without hydrogens. How to determine the r s configuration of a chiral center.
Video 4 of 5 in my in my fischer projection series shows you how to quickly and easily convert newman projections from the staggered or eclipsed form into fischer projections. Realistic representation of stereo structures of molecules edurev. Consider the following molecules written as newman projections and change them into the corresponding structure using fischer projections. In the last video, we visualized an ethane molecule with a newman projection. Find the chiral centers, assign the priorities and make your assignments. How to convert fischer and wedge dash projection to newman. For each of the following, draw the best and worst newman projection, relative to the bond indicated. In this video we explained interconversion of fischer projection and dash and wedge formula.
B nucleophilic substitutions at saturated carbon 8 l the reaction mechanism. Interconversion of fischer, newman and sawhorse projections, molecules with more than one chiral center, threo and erythro isomers, methods of resolution, optical purity, enantiotopic and diastereotopic atoms, groups and faces, stereospecific and stereoselective synthesis. Then, what you can do is rotate it so its more diagonally oriented. For the eclipsed sawhorse, ive rotated the frontleft bond to orient the hydride axially, and then for the staggered sawhorse, ive modified the eclipsed sawhorse. Draw the wedge dash projection from the newman projection and try and name the compounds from the newman projection and from the wedge dash projection. Jun 23, 2015 video 4 of 5 in my in my fischer projection series shows you how to quickly and easily convert newman projections from the staggered or eclipsed form into fischer projections. Now lets convert these sawhorse projections to newman projections. The method describes how students can look at their own hands as models for the visualization and interconversion. How can a fischer projection formula be converted into newman. The fischer projection formula of mesotartaric acid has a plane of symmetry. Interconversion of projection and perspective formulae. Newman projections if youre seeing this message, it means were having trouble loading external resources on our website.
Jul 11, 2015 test your fischer projections skills with this short quiz including questions on chirality and stereochemistry, conversion of fischer to newman, sawhorse and 56 membered sugar rings. Interconversion of sawhorse projection formula to fischer projection via newman projection and viceversa. Cyclohexane chair analysis newman projections and practic. Interconversion of fischer and zigzag projections learning stereochemistry with the help of hands article pdf available in resonance 154. Interconversion of fischer and zigzag projections learning. You see the problem can be given that how to convert a fischer projection into a newman projection or a saw horse or vice versa. To see the four steps for changing newman projections into fischer projections, click here. Dglucopyranose i which stereoisomer of ribose is this. Fischer projections, haworth structures and chair conformers the acyclic structure of a sugar is commonly drawn as a fischer projection. Problem 8 draw a 3d newman projection and a sawhorse representation for each the following fischer projections. Interconversion of fischer, newman and sawhorse projections. R and s nomemclature problem 3 classify the absolute configuration of all chiral centers as r or s in the molecules below.
This concept is explained concisely by iitian faculty. Each type of structure allows a different perspective on the molecule. Identify the highest and lowest energy conformations for the following molecules. What is the process to convert sawhorse projections into. Newman projections are one way to look at the conformation of a noncyclical molecule. Notice that the arrangement of functional groups around each carbon centre represents a y. The procedure is also applicable for drawing newman projections of chair conformations. Axial chirality biphenyls, allenes and spiranes r and s notations. Conversion of newman, sawhorse and fischer projection. This process is very similar to the method for converting sawhorse projections into fischer projections. So instead of me rambling on about why this and why that, lets go over how to do it.
But these projections have their own sets of rules and conventions for how you can rotate and move them. In this lesson, will learn how to convert a fischer representation into the sawhorse which is also important for the reaction mechanism. Test your fischer projections skills with this short quiz including questions on chirality and stereochemistry, conversion of fischer to newman, sawhorse and 56 membered sugar rings. Finally, the steps on changing a sawhorse projection into a fischer projection will be given. Changing sawhorse projections into fischer projections. Threo and erythro isomers, methods of resolution, stereo specific and stereoselective synthesis. Newman projections are used to represent the relationship between two carbons in a molecule. Conversion of newman, sawhorse and fischer projection dash. Draw the newman projection the wedge and dash projection. Zigzag fischer sawhorse newmann projection interconversion. In this lesson, will learn about the interconversion from newmann to fischer representation. In fischer projection, the crosses or the intersection represent the chiral centres of the molecule. As shown here, the two main ways to rotate a fischer projection are as follows.
Mar 22, 2012 the interconversion between the perspective formulae and newman projections is illustrated here. These can be converted into newman projections or other structures which show 3dimensional representations of molecules. Worksheet on newman and wedge dash projections key i would suggest doing the book problems first then attempting these. Interconversion of projection formula edubuzz notes. Newmanprojectionpractice 1 organic chemistry i jasperse newman projection practice a. Reactivity at a saturated carbon atom, available pathways, the sn1 mechanism, sn2 mechanism. Fischer, newman and sawhorse projections and their interconversion. Converting newman to fischer projections vid 4 of 5.
The front carbon is not written but is located at the. To consider the minutes of the meeting of the board of. Effect of confirmation on reactivity in acyclic compounds and cyclohexanes. Converting newman to fischer projections vid 4 of 5 youtube.
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