1. more examples of addition of hydrogen halides to alkenes: all symmetric

2. What if alkene is asymmetric? Which product forms? only tert-butyl chloride forms regiochemistry explained by mechanism constitutional isomers

3. more stable carbocation

7. what does the TS look like?

8. Hammond postulate: TS most resembles species which is closest in energy TS III resembles product TS I resembles reactant

9. tert-butyl cation forms faster – carbocation formation is rds

10. electrophilic addition reactions are regioselective

11. Markovnikov rule: electrophile adds to sp2 carbon that is bonded to greater # of carbons

12. not regioselective: (draw carbocation intermediates)

13. anti-Markovnikov addition of HBr

14. will give mix of 2 and 3-bromo product 2-bromo only synthesis problem:

15. acid-catalyzed addition of water to alkenes

18. catalyst regenerated

19. acid-catalyzed addition of alcohol

21. What’s happening here?

22. carbocation rearrangement hydride shift

23. alkyl (methyl) shift

24. ring expansion

25. addition of bromine to alkenes

26. more stable than carbocation

29. haohydrin formation

31. explaining regioselectivity this carbon has more + character

32. more variations:

33. oxymercuration-reduction: adding water without rearrangements

36. source of :H -

37. converting alkenes to epoxides

39. concerted reaction:

40. hydroboration-oxidation: anti-Markovnikov addition of water

45. (don’t worry about mechanism of oxidation step, Bruice p. 187)

47. catalytic hydrogenation of alkenes

51. heats of hydrogenation can be used to compare stability of alkenes notice: more substituted – more stable

53. also: trans more stable than cis

55. should be able to show how to do all of these transformations: