Advices For Studying Organic Chemistry

HO C

CH 3

H

CH 2

CH 3

14

2 or 3

2 or 3

⇒

HO C

C

H

C

C

14

H H

HH H

HH H

3 (H, H, H)

2 (C, H, H)

3. View the molecule with the group of lowest priority pointing away from us.
   
   
   1. If the direction from highest priority (4) to the next highest (3) to the next (2) is
      clockwise, the enantiomer is designated R.
   
   
   2. If the direction is counterclockwise, the enantiomer is designated S.
   
   
   
   

(L)-(+)-Lactic acid

HC

CH 3

OH

O

COOH

1

2

3 H

COOH

CH 3

C

(^1) H
2
4 3
S configuration (left turn on steering wheel)
(D)-(−)-Lactic acid
HC
OH OH
CH 3
COOH
1
2
3
COOH
H 3 C
C
H^1
2
(^34)
R configuration (right turn on steering wheel)
Assignment of configuration to (S)-(+)-lactic acid and (R)-(–)-lactic acid