1. Stereochemistry 3 By: Dr. Shatha Alaqeel

2. Meso compounds

3. Racemic Mixture

4. FISCHER PROJECTION

5. ASSIGNING R,S CONFIGURATIONS TO FISCHER PROJECTIONS 1) Assign priorities to the four substituents. 2) The group of the least priority has to be on a vertical bond. 3) Determine the direction of rotation in going from priority 1 to 2 to 3, and assign R or S configuration.

7. 4) If the group with the least priority is on a horizontal bond, the answer you get from the direction of the arrow will be the opposite of the correct answer.

8. How enantiomers can be separated? Can not be separated by usual techniques because of the similar physical properties. There are mainly 2 techniques for separation: 1) By crystalyzation then separating the 2 types of crystals using a pair of tweezers. 2) By column chromatography using a chiral stationary phase 3) By HPLC

9. Stereochemistry of Organic Reactions Retention of configuration استعادة الهيئة الفراغية

10. 2- Inversion of configuration تحول الشكل الفراغي S N 2 Reactions

11. 3-Racemization الرسمزة S N 1