Isomers

Isomers

same molecular formula but different structure

Constitutional Isomer

same chemical composition but differs in the order of bonds

Stereoisomer

same chemical composition and same order of bonds, but differ in spatial arrangement

Enantiomer

nonsuperimposable mirror images- D & L stereoisomers

D isomer

the penultimate -OH is on the right, Fisher diagram

L isomer

penultimate -OH is on the left, Fisher diagram

Diastereoisomer

not mirror images

Epimer

diastereoisomer- differs at one of several asymmetric carbon atoms

Anomer

diastereoisomer- differs at a new, asymmetric carbon formed after ring closure- alpha & beta anomers

Alpha anomer

diastereoisomer- the anomeric carbon C1 OH is trans to the CH2OH relative to the plane of the ring

Beta anomer

diastereoisomer- the anomeric carbon C1 OH is cis to the CH2OH relative to the plane of the ring