Conditions d’achèvement
A) Definition
Two configurational stereoisomers are called diastereomers if they are not enantiomers.The maximum number of configurational stereoisomers due to n asymmetric atoms is 2n.
Ø Stereoisomerism relation ships between molecules with two asymmetric atoms. 1st case: the asymmetric atoms do not have all three substituents identical. ⇒ there are 4 stereoisomers.
Example of 2,3,4-trihydroxybutanals:
2nd case: asymmetric atoms carry the same three substituents
⇒ there are 3 stereoisomers
Example of 2,3-dihydroxybutanedioic acids, or tartaric acids:
