ORGANIC CHEMISTRY 3540

STEREOCHEMISTRY

ABSOLUTE CONFIGURATION - R, S

ENANTIOMERS

"MIRROR IMAGE ISOMERS"

HAVE ALL PHYSICAL PROPERTIES THE SAME EXCEPT:

DIRECTION OF OPTICAL ROTATION
INTERACTION WITH A CHIRAL ENVIRONMENT (CHIRAL SOLVENT, ETC.)

CONFIGURATION

DESCRIBE BY SKETCHING MOLECULE

RELATE IT TO A STANDARD (D-GLUCOSE)

MEMORIZE THEM!

OR...

ABSOLUTE CONFIGURATION

ABSOLUTE CONFIGURATION USES THE SEQUENCE RULES TO DESCRIBE STEREOCHEMISTRY

DESIGNATE A MOLECULE AS R OR S.

METHOD

EXAMPLE

EXAMPLE

GIVE A THREE DIMENSIONAL DRAWING OF (R)-2-AMINOPROPANOIC ACID

NOTE: YOU CAN DESCRIBE THE ABSOLUTE CONFIGURATION WITH R OR S OR YOU CAN GIVE THE OPTICAL ROTATION WITH (-) OR (+).

BUT THERE IS NO ONE TO ONE RELATIONSHIP, SOME R ISOMERS ARE (-) AND SOME R ISOMERS ARE (+).

WHICH IS R AND WHICH IS S?