Stereoisomeric relationships Video transcript - [Instructor] On the left we have a Fischer projection, which is just another way of representing a molecule. And Fischer came up with these when he was working with carbohydrates, and he actually won the Nobel Prize for his chemistry. At the center here at the intersection of these lines, we have a carbon, and this carbon is a chirality center. There are four different groups attached to this carbon.
D-glucose chain All nonterminal bonds are depicted as horizontal or vertical lines.
The carbon chain is depicted vertically, with carbon atoms represented by the center of crossing lines. The orientation of the carbon chain is so that the C1 carbon is at the top. On a Fischer projection, the penultimate next-to-last carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right.
L sugars will be shown with the hydrogen on the right and the hydroxyl on the left. Swapping two pairs of groups attached to the central carbon atom still represents the same molecule as was represented by the original Fischer projection.
When creating a Fischer projection for a carbohydrate with more than three carbons, each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view. However this does not alter the Fischer projections for any previous carbons.
According to IUPAC rules, all hydrogen atoms should preferably be drawn explicitly; in particular, the hydrogen atoms of the end group of carbohydrates should be present.
Usage[ edit ] Fischer projections are most commonly used in biochemistry and organic chemistry to represent monosaccharides. They can also be used for amino acids or for other organic molecules, although this is discouraged by the IUPAC recommendations. The groups on the right hand side of a Fischer projection are equivalent to those below the plane of the ring in Haworth projections.Fischer projection, Method of representing the three-dimensional structures of molecules on a page, devised by Emil Fischer.
By convention, horizontal lines represent bonds projecting from the plane of the paper toward the viewer, and vertical lines represent bonds projecting away from the viewer. - [Instructor] On the left we have a Fischer projection, which is just another way of representing a molecule.
And Fischer came up with these when he was working with carbohydrates, and he actually won the Nobel Prize for his chemistry. The Fischer projection, devised by Emil Fischer in , is a two-dimensional representation of a three-dimensional organic molecule by projection.
Fischer projections were originally proposed for the depiction of carbohydrates and used by chemists, particularly in organic chemistry and biochemistry. Fischer Projections Introduction to Fischer Projections The wedge and dash representations of stereochemistry can often become cumbersome, especially for large molecules which contain a number of stereocenters.
An alternative way to represent stereochemistry is the Fischer Projection, which was first used by the German chemist Emil Fischer.
2. If one group of the Fischer projection is held steady, the other groups can be rotated either clockwise or counter clockwise. (R)-(+)-glyceraldehyde still (R)-(+)-glyceraldehyde CHO CH 2 OH H OH hold this group steady CHO OH HOH 2 C H Assigning R and S-configurations to Fischer projections 1. Fischer Projections.
Fischer Projections are abbreviated structural forms that allow one to convey valuable stereochemical information to a chemist (or biochemist) without them having to draw a more detailed 3D structural representation of the molecule.