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 (achiral compound 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. c = concentration in g/mL
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 Sucrose Camphor MSG Cholesterol Morphine

11. Chirality Center Carbon has four different groups attached

12. Enantiomers nonsuperimposible mirror images

30. Enantiomeric Excess (Optical Purity)

32. Absolute Configuration

33. Assign Priority to each Group on Asymmetric Center

34. Lactic Acid

35. C.I.P. Priorities

36. Fischer Projections

37. Assigning Absolute Configuration to Fischer Projections

38. Rotation of the Projection 90o Reverses Absolute Configuration

39. Diastereomers Stereoisomers That Are Not Mirror Images

40. Fischer Projections with 2 Chiral Centers

42. Identical, Enantiomers or Diastereomers?

43. Tartaric Acids

45. Racemic Mixture

46. Meso Compound Internal Plane of Symmetry Optically Inactive

47. 2,3,4-trichlorohexane How many stereoisomers?

48. n = 3; 2n = 8

49. A Carbohydrate

50. Internal Planes of Symmetry

51. Asymmetric Centers on Rings

52. Allenes can be Chiral

53. Mycomycin, an antibiotic

54. Reactions that Generate Chirality Centers Hydrogenation, syn

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

56. Bromonium Ion is Opened Equally from Both Sides

57. trans alkene + anti addition = MESO

58. cis Alkene + anti addition = racemic mixture

59. Brominations Often Generate Asymmetric Centers

60. Asymmetric Center is Generated Racemic Mixture Formed

116. New chiral P,N-ferrocenyl iminophosphine, Prepared in the asymmetric allylic alkylation of 1,3-diphenylprop-2-en-1-yl acetate with dimethylmalonate in different solvents. Quantitative yields and enantiomeric excesses as high as 80%

118. Asymmetric Induction

120. Biological Discrimination
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Chapter 5

121. Biological Activity

122. SSRI Efficacy depends on Stereochemistry

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

124. Relevance of Stereochemistry

125. One-step synthesis

126. a-(p-isobutylphenyl)propionic acid

127. Model of Thalidomide

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

129. Sildenafil (Viagra) and Caffeine

130. Radiosensitizer of Choice Until 2004