DAT Organic Chemistry
Isomers
Molecules that have the same chemical formula, but different arrangement of atoms
Conformational Isomers
Stereoisomers that differ by rotation about one or more single bonds, usually represented using
Newman projections
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Constitutional Isomers
same molecular formula, different connectivity
Stereoisomers (Enantiomers and Diastereoisomers)
Same formula, same connectivity, DIFFERENT 3D Orientation (Hands)
Enantiomers (R/S naming)
Mirror images that do NOT overlap (superimpose), same connectivity, exact opposite R/S, same
physical properties (bp,melting), DIFFERENT optical rotation of light (opposites)
Diasteroisomers (Cis/Trans/E/Z)
NOT mirror images, different physical properties, do NOT have EXACT opposite R/S, no
relation with optical rotation
, Epimers
diastereomers that differ at only one chiral carbon
Anomers
sugars that are diasteromers, differing only in the position of the hydroxyl at the anomeric
carbon
Meso Compound (SUPERIMPOSABLE)
A compound with chirality centers and an internal plane of symmetry causing it to be an achiral
molecule (at least two chiral centers)
Stereocenters vs Stereoisomers
Stereocenters: how many SINGLE chiral centers in a molecule
Stereoisomers: number of single chiral centers superscripted to 2n formula (2^n); n = number of
chiral centers
Chirality Center (Stereo centers)
Carbon center that contains four unique substituents
Cahn-Ingold-Prelog priority rules
The higher the atomic number, the higher the priority. (Z) Alkene is one where the
highest-priority substituents on each carbon are on the same side of the double bond. (E)
Alkene is one where the highest-priority substituents on each carbon are on the opposite side.
Clockwise =
R
Counterclockwise =
S
Fischer Projection R/S
4th priority to be on vertical (middle)
Isomers
Molecules that have the same chemical formula, but different arrangement of atoms
Conformational Isomers
Stereoisomers that differ by rotation about one or more single bonds, usually represented using
Newman projections
Previous
Play
Next
Rewind 10 seconds
Move forward 10 seconds
Unmute
0:00
/
0:15
Full screen
Brainpower
Read More
Constitutional Isomers
same molecular formula, different connectivity
Stereoisomers (Enantiomers and Diastereoisomers)
Same formula, same connectivity, DIFFERENT 3D Orientation (Hands)
Enantiomers (R/S naming)
Mirror images that do NOT overlap (superimpose), same connectivity, exact opposite R/S, same
physical properties (bp,melting), DIFFERENT optical rotation of light (opposites)
Diasteroisomers (Cis/Trans/E/Z)
NOT mirror images, different physical properties, do NOT have EXACT opposite R/S, no
relation with optical rotation
, Epimers
diastereomers that differ at only one chiral carbon
Anomers
sugars that are diasteromers, differing only in the position of the hydroxyl at the anomeric
carbon
Meso Compound (SUPERIMPOSABLE)
A compound with chirality centers and an internal plane of symmetry causing it to be an achiral
molecule (at least two chiral centers)
Stereocenters vs Stereoisomers
Stereocenters: how many SINGLE chiral centers in a molecule
Stereoisomers: number of single chiral centers superscripted to 2n formula (2^n); n = number of
chiral centers
Chirality Center (Stereo centers)
Carbon center that contains four unique substituents
Cahn-Ingold-Prelog priority rules
The higher the atomic number, the higher the priority. (Z) Alkene is one where the
highest-priority substituents on each carbon are on the same side of the double bond. (E)
Alkene is one where the highest-priority substituents on each carbon are on the opposite side.
Clockwise =
R
Counterclockwise =
S
Fischer Projection R/S
4th priority to be on vertical (middle)
