Fischer Projections

Fischer projections are another way of visually representing chirality.

Chiral compounds are generally drawn using dashed and wedged lines to illustrate three dimensions; however, when a compound contains multiple adjacent chiral centers, a Fischer projection is much more efficient to use. A Fischer projection is a projection that represents a molecule's three-dimensional structure. The steps for converting a bond line structure into a Fischer projection are:

1. The bond line structure, which is drawn from left to right, will be reoriented from top to bottom.

2. All the carbon-carbon bonds of the parent chain will be placed in the plane of the paper or projected behind the plane.

3. The dashed and wedged groups of the substituents will be placed coming out of the plane of the paper.

4. All the dashed bonds are replaced with vertical lines, and wedged bonds are replaced with vertical lines.

5. The vertical lines represent the carbon chain, the carbon atoms in the chain are represented by the intersection of the vertical and horizontal lines, and the horizontal lines are bonds that project out of the paper toward the viewer.

6. For the superposibility of Fischer projections, projections may be rotated in the plane of the paper 180° or 90°, but may not be flipped over.

Fischer Projection Conversion

To convert a bond line structure to a Fischer projection, the bond line structure is rotated vertically with the horizontal groups as wedges, and then the wedges and dashes are removed and replaced with horizontal and vertical lines.