1. Alkene Reactions, Section 2

2. Radical Halide Addition
Reaction of Alkenes with HBr (with radical formation).
Reaction Type: Radical Addition;
1 reduced (H) and 1 oxidized (X)
Overall Reaction: HBr + alkenes 
Hydrogen Halide Reactivity Order:
Regioselectivity: ____Markovnikov (goes through most stable free radical intermediate). C H 3 2 C H 3 2 B r h u 2

3. Radical Halide Addition
Reaction of Alkenes with HBr (with radical formation).
Stereoselectivity:
Mechanism includes a planar free-radical.
Requirements.
___________________initiate radical reaction via:
RO + HBr  ROH + Br 2

4. Radical Halide Addition
Mechanism: H C 2 3 B r H C 2 3 B r H B r H H B r C H H 3 2

5. Non-Radical vs. Radical Addition
Conditions
Electrophile
Intermediate
Regioselectivity 2

6. Overall Reaction: Alkenes + Acids 
Hydration
Reaction Type:
Overall Reaction: Alkenes + Acids 
Regioselectivity: _______Markovnikov’s Rule (_______________intermediate).
Stereoselectivity:
Requirements: Aqueous acid (usually H2SO4). . 2

7. Hydration H C 3 + 2 O H C 3 H C 3 H H C H H 3
_________________act as Lewis Base, _____ is electrophile, water acts as ___________. 2

8. Follows Markovnikov's Rule
50% H2SO4
50% H2O
CH2 4

9. Suppose you wanted to prepare 1-decanol from 1-decene?
Synthesis
Suppose you wanted to prepare 1-decanol from 1-decene? OH
Needed: a method for hydration of alkenes with a regioselectivity ___________ Markovnikov's rule. 13

10. Hydroboration Oxidation
Reaction Type:
Overall Reaction: Alkenes 
Regioselectivity: ______Markovnikov’s Rule
Stereoselectivity:.
Requirements: – Electrophilic Addition
– Oxidation 2

11. Hydroboration OxidationC 2 3 B t R e p a 2 x H C 2 3 B R H C 3 B H 2 H O - H C 2 3 B R O _ H C 2 3 O B R _ + O H H C 2 3 O - H C 2 3 O H O R e p a t c y l 2 + B R 2 O H 2

12. Hydroboration Oxidation
Step 1: H C 2 3 B H C 3 B H 2 2

13. Hydroboration Oxidation
Step 2: t R e p a 2 x H C 2 3 B H C 2 3 B R 2

14. Hydroboration Oxidation
Step 3: H C 2 3 B R O _ H C 2 3 B R H O - 2

15. Hydroboration Oxidation
Step 4: H H C 2 3 O B R H C C H C H 2 3 _ B R 2 H O O 2

16. Hydroboration Oxidation
Step 5: H C 2 3 O B R H C 2 3 O - _ + O H + B R 2 O H 2

17. Hydroboration Oxidation
Step 6: H C 2 3 O - H C 2 3 O H O 2

18. Overall Reaction: Alkene  Regioselectivity: ___Markovnikov’s Rule
Halogenation
Reaction Type:
Overall Reaction: Alkene 
Regioselectivity: ___Markovnikov’s Rule
(_______ acts as electrophile).
Reactivity Order:
Stereoselectivity:
Requirements: 2

19. Mechanism: Reaction proceeds via _________ __________ ion.
Halogenation
Mechanism: Reaction proceeds via _________ __________ ion. B r B r B r - B r 2

20. Formation of Bromonium Ion11

21. Example
Br2
CH3CH
CHCH(CH3)2
CHCl3
0°C 4

22. Overall Reaction: Alkene  vicinal Regioselectivity:
Halohydration
Reaction Type:
Overall Reaction: Alkene  vicinal
Regioselectivity:
Stereoselectivity:
Requirements: X2/H2O or HOX (hypohalous acid). 2

23. Halohydration
Mechanism: B r O B r O B r H + 3 H 2 O B r Br H 2 O 2

24. Examples
H2O
H2C
CH2 +
Br2 OH
Cl2 H
H2O 6

25. Regioselectivity CH3 OH C CH2Br H3C C CH2 Br2 H2O (77%)
Markovnikov's rule applied to halohydrin formation: the halogen adds to the carbon having the ____________ number of hydrogens. 32

26. are examples of heterocyclic compounds
Epoxides
are examples of heterocyclic compounds
three-membered rings that contain oxygen
H2C
CH2 O
H2C
CHCH3 O 2

27. Overall Reaction: Alkene  Regioselectivity: Stereoselectivity:
Epoxidation
Reaction Type:
Overall Reaction: Alkene 
Regioselectivity:
Stereoselectivity:
Requirements: 2

28. Epoxidation
Mechanism: - O R + H d H O - d + d + O d R O 2

29. Example
+ CH3COOH O
+ CH3COH O 7

30. Overall Reaction: Alkene 
Ozonolysis
Reaction Type:
Overall Reaction: Alkene 
Requirements: Ozone,
Reductive work up
(Zn in acetic acid; HC2H3O2). 2

31. Epoxidation Mechanism: + _ O O O " R ' H O H R " R ' R R " ' C H O + R
2nd C-O is formed by nucleophilic O attacking other end of C=C
Mechanism: + _ O O O
Step 1: Pi bond acts as nucleophile, attacks O3 on electrophilic terminal O.
" R ' H O
Step 2: Cyclic ozonide rearranges to the malozonide. H R
" R ' R R
" ' C H O + R
" ' C O H
Step 3: Work up. Zn/acetic acid makes malozonide decompose to two carbonyl groups. 2

32. Example
CH3
CH2CH3 H C
1. O3
2. H2O, Zn 19