1. 1 13.6 Chiral Molecules Chapter 13 Organic Compounds with Oxygen and Sulfur Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

2. 2 Chiral Objects Chiral objects have the same number of atoms arranged differently in space. have one or more chiral carbon atoms each of which is bonded to four different groups. are like your hands. Try to superimpose your thumbs, palms, back of hands, and little fingers. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

3. 3 Mirror Images The mirror images of chiral compounds cannot be superimposed. When the H and I atoms are aligned, the Cl and Br atoms are on opposite sides.

4. 4 Achiral Structures are Superimposable When the mirror image of an achiral structure is rotated, the structure can be aligned with the initial structure. Thus this mirror image is superimposable.

5. 5 Some Everyday Chiral and Achiral Objects

6. 6 Learning Check Identify each as a chiral or achiral compound. A CH 2 CH 3 HCH 3 Cl C B H HCH 3 Cl C C Br HCH 3 Cl C

7. 7 Solution Identify each as a chiral or achiral compound. chiral achiral chiral A CH 2 CH 3 HCH 3 Cl C B H HCH 3 Cl C C Br HCH 3 Cl C

8. 8 Fischer Projections A Fischer projection is a 2-dimensional representation of a 3-dimensional molecule. places the most oxidized group at the top. uses vertical lines in place of dashes for bonds that go back. uses horizontal lines in place of wedges for bonds that come forward.

9. 9 Drawing Fischer Projections

10. 10 D and L Notations By convention, the letter L is assigned to the structure with the —OH on the left. The letter D is assigned to the structure with the —OH on the right. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

11. 11 Learning Check Indicate whether each pair is a mirror image that cannot be superimposed (enantiomers).

12. 12 Solution Indicate whether each pair is a mirror image that cannot be superimposed (enantiomers). Yes No