Show a synthetic pathway

1. Show a synthetic pathway

2. Show a synthetic pathway Hint: Alkenes may be formed from alkyl halides by reaction with a strong base such as NaOCH3 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 – 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 (an achiralcompound 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 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

14. 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

15. Chirality CenterCarbon has four different groups attached

16. Enantiomersnonsuperimposible 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

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 90oReverses Absolute Configuration Translation: If you rotate the Fisher projection 90o you are drawing the opposite enantiomer!

31. Determine the stereochemistry at all chiral centers.

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

34. DiastereomersStereoisomers That Are Not Mirror Images

35. Fischer Projections with 2 Chiral Centers

36. 2 Chiral Centers4 Stereoisomers

37. Identical, Enantiomers or Diastereomers?

38. Identical, Enantiomers or Diastereomers? S-2-Bromobutane S-2-Bromobutane (2R,3S)-3-aminobutan-2-ol (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 CompoundInternal Plane of SymmetryOptically Inactive

42. 2,3,4-trichlorohexaneHow many stereoisomers?

43. n = 3; 2n = 8

44. A Carbohydrate

45. Internal Planes of Symmetry

46. Asymmetric Centers on Rings

47. Reactions that Generate Chirality Centers Hydrogenation, syn

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

49. Bromonium Ion is Opened Equally from Both Sides

50. trans alkene + anti addition = MESO