1. Show a synthetic pathway

2. Hint: Alkenes may be formed from alkyl halides by reaction with a strong base such as NaOCH 3 resulting elimination of HX.

4. Fill in the blanks.

5. 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.

7. 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

8. More Definitions Asymmetric center – sp 3 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 (an achiral compound will not rotate light) Polarimeter – device that measures the optical rotation of the chiral compound

9. Plane-Polarized Light

10. Plane-Polarized Light through an Achiral Compound

11. Plane-Polarized Light through a Chiral Compound

12. Polarimeter Measures Optical Rotation

13. Specific Rotation, [α] [α] = α / cl  = 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

14. Specific Rotations of some Common Organic Compounds Compound[  ]# * centers Penicillin V +233.03 Sucrose +66.5 10 Camphor +44.32 MSG +25.51 Cholesterol -31.38 Morphine -132.05

15. Chirality Center Carbon has four different groups attached

16. Enantiomers nonsuperimposible mirror images

17. Absolute Configuration

18. Assign Priority to each Group on Asymmetric Center

19. Lactic Acid

20. C.I.P. Priorities

21. Enantiomeric Excess (Optical Purity)

23. SSRI Efficacy depends on Stereochemistry (+/-) Celexa(-) Lexapro Cost $17.10 per month$83.83 per month

24. Art in Chemistry Lexapro is the S enantiomer. Draw the structure of Lexapro.

25. Art in Chemistry Lexapro contains only the S enantiomer. Celexa is a racemic (50:50) mixture of both S and R forms.

26. Biological Activity In the 50’s, thalidomide was sold as a racemic mixture!

27. Thalidomide was prescribed as a sedative and used against nausea and to alleviate morning sickness in pregnant women.

28. Fischer Projections

29. Assigning Absolute Configuration to Fischer Projections

30. Rotation of the Projection 90 o Reverses Absolute Configuration Translation: If you rotate the Fisher projection 90 o you are drawing the opposite enantiomer!

31. Determine the stereochemistry at all chiral centers.

33. (7) Should be R, R, S, R from C-1; 5 th chiral center not included. 1

34. Diastereomers Stereoisomers That Are Not Mirror Images

35. Fischer Projections with 2 Chiral Centers

36. 2 Chiral Centers 4 Stereoisomers

37. Identical, Enantiomers or Diastereomers?

38. S-2-Bromobutane (2R,3S)-3-aminobutan-2-ol

39. Tartaric Acids Solve one structure first. Make sure you do it correctly! Use it as reference for others.

40. Racemic Mixture

41. Meso Compound Internal Plane of Symmetry Optically Inactive

42. 2,3,4-trichlorohexane How many stereoisomers?

43. n = 3; 2 n = 8

44. A Carbohydrate

45. Internal Planes of Symmetry

46. Asymmetric Centers on Rings

47. Reactions that Generate Chirality Centers Hydrogenation, syn

48. Bromination Trans is formed exclusively No Meso is formed (cis)

49. Bromonium Ion is Opened Equally from Both Sides

50. trans alkene + anti addition = MESO

51. cis Alkene + anti addition = racemic mixture

52. Brominations Often Generate Asymmetric Centers

53. Asymmetric Center is Generated Racemic Mixture Formed

54. Asymmetric Induction

55. Preparation of (L)-Dopa for Treatment of Parkinson’s

56. Relevance of Stereochemistry

57. One-step synthesis

58.  -(p-isobutylphenyl)propionic acid

59. How Sweet it is! Sucralose is 600 times sweeter and does not get metabolized.

60. Sildenafil (Viagra) and Caffeine

61. Radiosensitizer of Choice Until 2004

62. How is each Cpd related to X?

63. Enantiomers: A, C Diastereomers: B, E, F, H, I Identical: D, G