A method of drawing
chiral molecules, like so:
R1
R2 + R3
R4
where each R is a
subgroup of the
chiral carbon (not represented, but assumed to be at the
junction of the vertical and horizontal lines). The R groups off the vertical line are behind the chiral carbon, and the R groups of the horizontal line are in front (giving a
three-dimensional shape to a
two-dimensional drawing).
The drawing can be rotated within two dimensions and still represent the same molecule. However, it cannot be rotated within three dimensions; this would yield an enantiomer or mirror-image molecule. The Fischer projection is based on the Fischer-Rosanoff convention** (the accepted drawing of D-glyceraldehyde) and is named for Emil Fischer, who did much of the groundbreaking research on sugar and purine structures. The Fischer projection is used mostly for drawing amino acids and simple sugars in the linear form.
In sugars, the alternate method of representation is the Haworth projection, which shows the more common ring structure.
See also:
amino acids, amino acid
monosaccharide stereochemistry, glucose
Emil Fischer
stoichiometry, stereo-chemistry, enantiomer
** - it is worth mentioning that Emil Fischer rejected the Rosanoff convention of
nomenclature, and that the name "Fischer-Rosanoff convention" is something of a misnomer. His name was presumably added as an
honorarium for the fact that he determined the structure and configuration of
glucose itself, and that the convention was designed as a standard for the
configuration of glucose and other sugars.