Question

Explain how the Fischer convention describes the absolute configuration of a chiral molecule.

Short answer

The configuration of a chiral molecule can be explained by relating its L-stereoisomer with L-glyceraldehyde. Two molecules can be in the same relative configuration if hydroxyl, aldehydic, ${\mathrm{CH}}_2\mathrm{OH}$, and H groups of glyceraldehyde are the same with a chiral molecule.

Step-by-step solution

Chiral molecule

These are the molecules without a plane of symmetry, so they are non-superimposable mirror images of each other.The term relating to this property is chirality, so the molecule has an asymmetric center.

Describing the configuration of a chiral molecule

Fischer convention is the commonly used method to explain the configuration of an asymmetric molecule by comparing it with another asymmetric compound, glyceraldehyde (1 chiral center). An example can be given in the case of $\mathrm{\alpha }$-amino acids:

Both the molecules exhibit the same groups around the${\mathbf{C}}_{\mathbf{\alpha }}$; thus, we can say L-glyceraldehyde and L-$\mathbf{\alpha }$-amino acid have same relative configuration.

Hence, Fischer convention describes that the chiral molecule's configuration can be related to L-glyceraldehyde, which has hydroxyl, aldehydic, ${\mathrm{CH}}_2\mathrm{OH}$, and H groups.