Steoreochemistry & Chirality - Chem

Chirality

when an object and its mirror image are non-superimposable

• an object is chiral if it CAN have an enantiomer

Chiral Centers

sp3 hybridized carbon, 4 unique surrounding groups, no double bond and no heteroatoms bonded to it

Enantiomers

Non geometric stereoisomers that have non superimposable mirror images

(same molecular formula, same connectivity, non-superimposable, mirror images)

• opposite chiral center absolute configuration

Diastereomers 

Non geometric stereoisomers that are nonsuperimposable and not mirror images of each other, must have at least two chiral centers 

• one same and one different chiral center absolute configuration

Achiral

Superimposable molecules that cannot have an enantiomer

Is it possible to have a chiral center in an achiral molecule?

Yes, but the molecule will have to have an internal plane of symmetry (attached/connected to exactly the same this)

Achiral molecule with chiral centers example:

Meso compounds

Meso compounds

achiral molecules with an even number of chiral centers

are attatched to the same thing

R+S (internal mirror)

to draw an enantiomer

switch groups

to draw diastereomer

keep on group same, change one group

identical molecules

same molecular formula, same connectivity, and are superimposable, same configuration