Enantiomers and Diastereomers

Enantiomers

isomers that are mirror images of each other

R,R and S,S

enantiomers

R,S and S,R

enantiomers

Diastereomers

stereoisomers that are not mirror images of each other

R,R and S,R

diastereomer

S,S and S,R

diastereomer

R,R and R,S

diastereomers

R,S and S,S

diastereomer

R,S and S,R if there are two chiral centers with the same 4 groups attached

same molecule

mesocompound

A molecule that contains a chiral center but is achiral as that it has a plane of symmetry.

Conditions for mesocompound

1. Two chiral centers
2. Same four groups for each chiral center
3. R,S or S,R
4. Achiral (plane of symmetry can be formed)

Fischer projection with hydroxyl being left of aldehyde

L

Fischer projection with hydroxyl being right of aldehyde

D

If amine is to the left of the carboxylic acid

L

If amine is to the right side of the carboxylic acid

D

dextrorotatory

clockwise rotation

levorotatory

counterclockwise

If there is more than 50% of S enantiomer or R enantiomer

Optically active

If 50/50 mix of R and S

Optically inactive

racemic mixture

a mixture of equal amounts of two enantiomers

Chiral centers on Fischer projections

whatever it looks like, it's the opposite only if H is one the horizontal part

Constitutional Isomers

compounds with the same molecular formula but different connections among their atoms