1. Chapter 5 Stereochemistry The Arrangement of Atoms in Space; The Stereochemistry of Addition Reactions

3. Molecular Chirality: Enantiomers

5. A molecule is chiral if its two mirror image forms are not superimposable upon one another. A molecule is achiral if its two mirror image forms are superimposable. Chirality

6. Br Cl H F Bromochlorofluoromethane is chiral It cannot be superimposed point for point on its mirror image.

7. Br Cl H F Bromochlorofluoromethane is chiral H Cl Br F To show nonimsuperposability, rotate this model 180° around a vertical axis.

8. Chirality & nonsuperimposable mirror images Enantiomers

9. Isomers stereoisomers constitutionalisomers

10. Isomers stereoisomers constitutionalisomers diastereomers enantiomers

11. Physical Properties of Enantiomers

12. Physical properties are the same: melting point, boiling point, density, etc Some others are different: properties that depend on the shape of molecule eg. biological-physiological and optical properties. Properties of enantiomers

13. O O CH 3 H3CH3CH3CH3C H3CH3CH3CH3C CH 2 Odor (–)-Carvone spearmint oil (+)-Carvone caraway seed oil

15. Ibuprofen is chiral, but normally sold as a racemic mixture. The enantiomer below is the one responsible for its analgesic and antiinflammatory properties. Chiral drugs CH 2 CH(CH 3 ) 2 H H3CH3CH3CH3C C O C HO

16. A Sedative or a Potent Teratogen?

18. a carbon atom with four different groups attached to it also called: chiral center; chiral carbon asymmetric center asymmetric carbon stereocenter stereogenic center The chiral carbon atom wx y z C

19. A molecule with a single stereogenic center is chiral. 2-Butanol is an example. Chirality and chiral carbons CH 3 OH H C CH 2 CH 3

20. Examples of molecules with 1 chiral carbon CH 3 C CH 2 CH 3 CH 2 CH 2 CH 2 CH 3 CH 3 CH 2 CH 2 a chiral alkane

21. Examples of molecules with 1 chiral carbon Linalool, a naturally occurring chiral alcohol OH

22. Examples of molecules with 1 chiral carbon 1,2-Epoxypropane: a chiral carbon can be part of a ring O H2CH2CH2CH2C CHCH 3 attached to the chiral carbon are: —H —CH 3 —OCH 2 —CH 2 O

23. Examples of molecules with 1 chiral carbon Limonene: a chiral carbon can be part of a ring CH 3 H C CH 2 attached to the chiral carbon are: —H —CH 2 CH 2 —CH 2 CH= —C=

25. Examples of molecules with 1 chiral carbon Chiral as a result of isotopic substitution CH 3 C D TH

26. A molecule with a single chiral carbon must be chiral. But, a molecule with two or more chiral carbons may be chiral or it may not. We’ll return to this when we consider molecules with more than one chiral carbon atom.