1. Alicyclics
Aliphatic compounds containing rings, cycloalkanes, cycloalkyl halides, cycloalkyl alcohols, cyclic ethers, cycloalkenes, cycloalkadienes, etc.

2. Cycloalkanes
cyclopropane cyclobutane cyclopentane cyclohexane

3. methylcyclopentane 1,1-dimethylcyclobutane
trans-1,2-dibromocyclohexane

5. cyclopentene 3-methylcyclohexene 1,3-cyclobutadiene
cycloalkenes 3 4 2 5 1 6
cyclopentene methylcyclohexene 1,3-cyclobutadiene

6. cyclohexanol ethyl cyclopentyl ether
cyclohexyl alcohol

7. Cycloalkanes, syntheses:
Modification of a ring compound:
1. reduction of cycloalkene
2. reduction of cyclic halide
a) hydrolysis of Grignard reagent
b) active metal & acid
3. Corey House
B. Ring closures

8. A. Modification of a cyclic compound:
H2, Ni
Sn, HCl
Mg; then H2O

9. Li
CuI
+ CH3CH2-Br
CH2CH3
must be 1o
Corey-House

10. ring closures
CH2=CH CH2CO, hv 
Br-CH2CH2CH2CH2CH2-Br Zn 
etc.

11. cycloalkanes, reactions:
halogenation
2. combustion
3. cracking
4. exceptions
Cl2, heat
+ HCl

12. exceptions: H2, Ni, 80o CH3CH2CH2-I CH3CH2CH3 Cl2, FeCl3
Cl-CH2CH2CH2-Cl
H2O, H+
CH3CH2CH2-OH
conc. H2SO4
CH3CH2CH2-OSO3H HI
CH3CH2CH2-I

13. exceptions (cont.)
+ H2, Ni, 200o  CH3CH2CH2CH3
??????????

14. internal bond deviation heat of
angles from combustion
60o o
90o o
108o -1.5o

15. Cyclopropane undergoes addition reactions that other cycloalkanes and alkanes do not. This is because of angle strain in the small ring. Because the bond angles are less than the optimal 109.5o for maximum overlap, the bonds are weaker than normal carbon-carbon single bonds and can be added to.
Cyclobutane has angle strain that is less than that for cyclopropane, reacts with H2/Ni at a higher temperature, but does not react like cylcopropane in the other exceptional reactions.

16. internal bond deviation heat of
angles from combustion
60o o
90o o
108o -1.5o
120o o
128.5o +19o
135o o

17. Cyclohexane does not have any angle strain. It isn’t a flat molecule
Cyclohexane does not have any angle strain! It isn’t a flat molecule. By rotating about the carbon-carbon bonds, it can achieve 109.5o bond angles.

18. conformations of cyclohexane
chair twist boat
boat

19. The chair conformation of cyclohexane is free of both angle strain and torsional strain (deviation from staggered). This is the most stable conformation.

20. The boat conformation is free of angle strain, but has a great deal of torsional strain (eclipsed). To relieve the strain, it twists slightly to form the twist boat:

22. a = axial positions in the chair conformation
e = equatorial positions

23. 
CH3 in axial position CH3 in equatorial position
is more stable

25. Cycloalkenes, syntheses:
Modification of a ring compound:
1) dehydrohalogenation of an alkyl halide
2) dehydration of an alcohol
3) dehalogenation of vicinal dihalides
(B. Ring closures)

26. KOH(alc)
H+, Δ
cyclohexene Zn

27. Cycloalkenes, reactions:
addition of H hydroboration-oxid.
addition of X addition of free radicals
addition of HX 10. addition of carbenes
addition of H2SO epoxidation
addition of H2O,H+ 12. hydroxylation
addition of X2 + H2O 13. allylic halogenation
oxymerc-demerc ozonolysis
15. vigorous oxidation

28. H2, Pt
Br2, CCl4
trans-1,2-dibromocyclohexane

30. HBr
H2SO4
H2O, H+
Markovnikov orientation

31. Br2 (aq.)
H+, dimer.
HF, 0o

33. HBr, peroxides
polymerization
CH2CO, hν
Peroxybenzoic acid

34. KMnO4 HCO3H Br2, heat cis-1,2-cyclohexanediol
trans-1,2-cyclohexanediol
Br2, heat

36. stereoselective

37. cyclic alcohols, halides, ethers as expected:
PBr3 Na H+
CH3COOH +
NaOCl

38. NaOH
2o alkyl halide => E2 Mg
H2O
conc. HI, heat
conc. HBr, heat
2 Br-CH2CH2-Br
1,4-dioxane

39. Alicyclic compounds are chemically like their open chain analogs
Alicyclic compounds are chemically like their open chain analogs. The exceptions are for small ring compounds where angle strain may give rise to reactions that are not typical of other molecules.

40. Epoxides: ethylene oxide propylene oxide cyclopentene oxide
(oxirane) (methyloxirane)
Synthesis:
C6H5CO3H
cis-2-butene
β-butylene oxide

41. acid catalyzed addition
epoxides, reactions:
acid catalyzed addition OH
CH2CH2
H2O, H+ OH
CH3CH2-O-CH2CH2
CH3CH2OH, H+ OH
CH2CH2 Br
HBr

42. 2. Base catalyzed additionOH
CH2CH2
CH3CH2-O-CH2CH2-OH
H2N-CH2CH2-OH
CH3CH2CH2CH2-OH

43. mechanism for acid catalyzed addition to an epoxide

44. mechanism for base-catalyzed addition to an epoxide:

45. OH + H2O, H+  CH3CHCH2 18OH CH3CHCH2 + H218O, H+  OH
acid catalyzed addition to unsymmetric epoxides? OH
+ H2O, H+  CH3CHCH2
which oxygen in the product came from the water?
18OH
CH3CHCH2 OH
+ H218O, H+ 

46. CH3 O
+ CH3OH, H+  CH3CHCH2 OH Br
+ HBr  CH3CHCH2 OH

47. Base?
18OH
+ Na18OH, H218O  CH3CHCH2 OH
OCH3
+ CH3OH, CH3ONa  CH3CHCH2 OH
NH2
+ NH3  CH3CHCH2 OH

48. Acid: Z
+ HZ  CH3CHCH2 OH
Base: Z
+ Z-, HZ  CH3CHCH2 OH

49. “variable transition state” Z acid: — C — C — OH ‡
Bond breaking is occurring faster than bond making, making the carbon slightly positive. C δ+ : 3o > 2o > 1o δ+ δ+
base: Z
— C — C — O ‡
Bond breaking is occurring at the same time as bond making, there is no charge on the carbon. Steric factors are most important: 1o > 2o > 3o δ-

50. Acid: Z + HZ  CH3CHCH2 OH Base: Z + Z-, HZ  CH3CHCH2 OH
Cδ+: Z to 2o carbon
Base: Z
+ Z-, HZ  CH3CHCH2 OH
steric factors: Z to 1o carbon