Unformatted text preview: 2.-or- use the “Hand Rule”. Orient the lowest priority group up. Point your thumb in the direction of the lowest priority group. If you need to use your right hand so that your fingers point in the direction of the group priorities in the order 1-2-3, then the stereogenic center is assigned R (“r ectus” or right ). If your left hand is required so that your fingers point in the direction of the group priorities 1-2-3, the the stereogenic center is assigned S (“s inister” or left ). (S)-(+)-Lactic acid (Left Hand) (R)-(-)-Lactic acid (Right Hand) H HO 2 C CH 3 OH 4 2 3 1 H CO 2 H H 3 C HO 4 2 3 1...
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- Fall '08
- Mole, Left-handedness, Stereogenic Center, Clockwise, lowest priority group