1. Cyclohexane and its Stereochemistry
Organic Chemistry I
Fall, 2013
Day 9,10
9/23,25/13
Chapter 4
Cyclohexane and its Stereochemistry
Chem Act 7B

2. Cyclohexane C6H12 and Analogs

3. Axial and Equatorial

4. Cyclohexane Ring Flip How do you know it occurs ?

5. Visualizing Cyclohexane The Chair – Chem Act 7B Model 3

7. What kind of strain is there and Which cycloalkane is most strain free ?
Chem Act 7B Model 4

10. Strain in Substituted Cyclohexanes
ΔG = - RT ln K
ΔG (in kcal/mole) = log K
K log K ΔG
Why so large ?
Why so small ?

13. Stereochemistry at Tetrahedral Centers
Chemistry
Organic Chemistry I
Fall, 2013
Day 10
9/27/13
Chapter 5
Stereochemistry at Tetrahedral Centers
ChemAct 12A
Chirality

14. Venlafaxine = Effexor Chem Act 12A Model 1

15. Which of the following molecules possesses a plane of symmetry?
A only
B only
C only
A and C
B and C

16. Chirality and Objects in the World Chem Act 12A Model 2

17. Chem Act 12A Model 2 CTQ 6
6. Example of a molecule that is a. not chiral (achiral) b. chiral

18. Chem Act 12A Model 2 CTQ 7
7. Example of an everyday object that is a. not chiral (achiral) b. chiral

19. Which of the above molecules are achiral?
A and C
A and E
B and C
B and D
D and E

21. Tetrahedra with 2, 3 or 4 different groups

22. Chiral Compounds

23. Consequences of Chirality

24. Tetrahedra with 4 different groups

25. Problems 5.1, 5.2, 5.3, 5.4, 5.5
5.1) Which objects are chiral ? (a) soda can (b) screwdriver (c) screw (d) shoe
5.2) Which molecules are chiral ?

26. What is the relationship between the two compounds shown below?
they are identical
they are constitutional isomers
they are nonsuperimposable mirror images of each other
they are different conformations of the same compound
they have different atom connectivity

27. What do you call a 1:1 mixture of the two compounds below?
a 1 M solution
a racemic mixture
a non racemic solution
an optically active solution
a mixture of diastereomers

28. Stereoisomers
conformers
Fig. 9-14, p. 341

29. Stereoisomers

30. Enantiomers have identical chemical and physical properties in achiral environments. Diastereomers have different properties in chiral and achiral surroundings. What can be deduced based on the observation that A smells like citrus fruits, while B has an odor of pine trees?
A and B are diastereomers.
A and B are an exception to the rule and do not have the same properties.
The sense of smell cannot be used to deduce anything about the stereochemistry of A and B.
The olefactory receptors responsible for smell are chiral.
As can be observed by looking into a mirror, our noses are chiral.

31. Enantiomer Recognition

32. Q: How do you detect chirality ? A: Polarimetry ! Chem Act 12A Model 3
Q: How do you detect chirality ? A: Polarimetry ! Chem Act 12A Model 3

33. Which statement about chirality and optical activity is false?
If a solution shows optical activity, it must have a compound present whose mirror image is not superimposable on the compound itself.
Molecules with plane of symmetry will show no optical activity.
The angle of rotation of plane-polarized light depends on how many chiral molecules does the light interact with while passing through the sample.
Enantiomers will always have opposite signs of optical rotation.
All enantiomers are dextrorotatory.

34. Chem Act 12A Models 4, 5 and 6

36. How to specify chirality The Cahn-Ingold-Prelog Rules (R) and (S)

37. (R) and (S)

38. Absolute Configuration (R), (S) and Optical Rotation (d)(+), (l)(-)

39. Assign (R) or (S)
Problem 5.10, see page 156 S N

40. Problem 5-37 Assign (R) or (S) and what is the relationship of these pairs of molecules ?

41. 2 Stereogenic Centers (C*)

42. 2 Stereogenic Centers and a plane of symmetry