Test 2 Extra Stereochem Practice

Organic Chemistry I Test 2 Extra Stereochemistry Practice Problems Page 1 ... one chiral C, if you can ... D on't w orry about them . Title: Test 2 Ex...

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Organic Chemistry I

Test 2

Extra Stereochemistry Practice Problems

Page 1: Designate R/S Page 2: Chiral or Achiral?

Page 3: Same, Enantiomer, or Diastereomer?

A. Designate the R/S configuration for any chiral centers in the following molecules. Br

H Br 2.

1.

3.

H Br 4.

H 2N H

H

H OH

H OH

HO

HO 6.

5.

H OH

O

HO

9.

8.

H Br 10.

NH 2

O

7.

H OH

H OH

HO

H CH 3 OH

O

11.

H CH 3 N H

13.

O

H CH 3 O

12.

H OH 14.

O

HO

O

H OH NH 2

OH O

15.

H CH 3

H OH 18.

O

16.

17. R, not S. Error in movie

H OH

H

O 19.

H HO

H

CH 3 H

H NH O 2

H

CH 3

H

H 2N

23. H 3C NH 2

CH 3

CH 3

21. H

H

H Cl

28. 29.

HO CH 3

H CH2OH H O HO OH HO H H HO H

This one is very hard. But for each of the 5 chiral C's, the tie-breaking processes do work.

CH 3 HO

H OH O

27.

H 3C

30.

CH 3 H

24.

H CH 3 H 26.

HO

Br

H

25.

H

OH R,R, error in movie R,R which said R, S.

20.

CH 3

22.

H OH

CH 3

NH 2

H 3CO H

H

O

 

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B. Identify each of the following molecule as chiral or achiral. (By circling the chiral ones.) Write “meso” where it applies. (In other words, if it is achiral despite having chiral centers). One chiral carbon => chiral molecule

H CH 3 N H

31.

O

H OH 32.

HO

H OH NH 2

OH 33.

O H CH 3

H 3CO H 34. Two common attachments => achiral

35.

H 3CO H

H OH

H 3C H

H OH

37. Plane of symmetry => achiral

H

40.

O 39.

38.

Cl H Cl

H

36.

Cl Cl H

41.

H

H

Cl Cl H

42.

H

H Cl

43.

Cl H Cl

Cl

H

Cl H Br

45. 44. OH OH

46.

47.

OH

OH

49.

H

H Cl

51.

H H OH

50.

CH 3 Cl H CH 3

CH 3

48.

OH

H OH

T

OH

OH

Cl Cl

52.

CH 3 H H CH 3

H Cl 53.

CH(CH 3)2 Cl H CH 3

Problems 51-53, in which you need to translate from a Newman projection, are on the very very difficult end. If you want to challenge yourself, do them. But these are probably harder than you'll see on the test.

  With just one chiral C, if you can assign R/S for both, you can tell if same or different.

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C. Mark the relationships between the following structures as either “same”, “enantiomers”, or “diastereomers”. H

Cl

54.

H

Cl

H

Cl

Cl

H

H

Cl

H

Cl

H

Cl

55.

56.

H 3C

Cl

H

60.

62.

Cl

59.

Cl

58.

OH

OH

OH

OH

61.

64 + 66 have some tricky 64. "turningthem-over" issues. Don't worry about them.

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

65.

OH

OH

OH

OH HO

OH

H

OH

Cl

Cl

Cl

OH

67.

H

H Cl

H Cl H Cl

H

H Cl

69.

H H Cl

H H

Cl H H

OH

Cl H

73. OH

OH

H OH

OH

74.

CH 3 Cl H Cl

H CH 3

Cl

Cl Cl H H

Cl H

72.

Cl H Cl

H

H Cl H Cl

71.

Cl

Cl Cl H H

Cl

Cl

H Cl

OH

OH

OH

66.

76.

H

OH

63.

70.

Cl

H

57.

H

68.

H

Cl

H

75. Cl

Cl H Cl H

Cl

77.

H H OH CH 3 H H CH 3

OH OH H

Cl H Cl