1. Stereochemistry Stereochemistry refers to the 3-dimensional properties and reactions of molecules. It has its own language and terms that need to be learned in order to fully communicate and understand the concepts.

3. Definitions • Stereoisomers – compounds with the same connectivity, different arrangement in space • Enantiomers – stereoisomers that are non- superimposible mirror images; only properties that differ are direction (+ or -) of optical rotation • Diastereomers – stereoisomers that are not mirror images; different compounds with different physical properties

4. More Definitions • Asymmetric center – sp3 carbon with 4 different groups attached • Optical activity – the ability to rotate the plane of plane –polarized light • Chiral compound – a compound that is optically active (achiralcompound will not rotate light) • Polarimeter – device that measures the optical rotation of the chiral compound

5. Plane-Polarized Light

6. Plane-Polarized Light through an Achiral Compound

7. Plane-Polarized Light through a Chiral Compound

8. Polarimeter Measures Optical Rotation

9. Specific Rotation, [α] [α] = α / cl a = observed rotation c = concentration in g/mL l = length of tube in dm Dextrorotary designated as d or(+), clockwise rotation Levorotary designated as l or (-), counter- clockwise rotation

10. Specific Rotations of some Common Organic Compounds Compound [a] # * centers Penicillin V +233.0 3 Sucrose +66.5 10  Camphor +44.3 2 MSG +25.5 1 Cholesterol -31.3 8 Morphine -132.0 5

11. Chirality CenterCarbon has four different groups attached

12. Enantiomersnonsuperimposible mirror images

13. Enantiomeric Excess(Optical Purity)

15. Biological Activity

16. SSRI Efficacy depends on Stereochemistry

17. Absolute Configuration

18. Assign Priority to each Group on Asymmetric Center

19. Lactic Acid

20. C.I.P. Priorities

21. Fischer Projections

22. Assigning Absolute Configuration to Fischer Projections

23. Rotation of the Projection 90oReverses Absolute Configuration

24. DiastereomersStereoisomers That Are Not Mirror Images

25. Fischer Projections with 2 Chiral Centers

26. 2 Chiral Centers4 Stereoisomers

27. Identical, Enantiomers or Diastereomers?

28. Tartaric Acids

29. Racemic Mixture

30. Meso CompoundInternal Plane of SymmetryOptically Inactive

31. 2,3,4-trichlorohexaneHow many stereoisomers?

32. n = 3; 2n = 8

33. A Carbohydrate

34. Internal Planes of Symmetry

35. Asymmetric Centers on Rings

36. Allenes can be Chiral

37. Mycomycin, an antibiotic

38. Reactions that Generate Chirality Centers Hydrogenation, syn

39. BrominationTrans is formed exclusivelyNo Meso is formed (cis)

40. Bromonium Ion is Opened Equally from Both Sides

41. trans alkene + anti addition = MESO

42. cis Alkene + anti addition =racemic mixture

43. Brominations Often Generate Asymmetric Centers

44. Asymmetric Center is Generated Racemic Mixture Formed

45. Asymmetric Induction

46. Preparation of (L)-Dopafor Treatment of Parkinson’s

47. Relevance of Stereochemistry

48. One-step synthesis

49. a-(p-isobutylphenyl)propionic acid

50. Model of Thalidomide