Reactions

Question 1

Thermodynamic Product

Answer 1

Forms products slower and can be 1,2 or 1,4 (45 C)
- Regioselective to alkene and resonance stability

Question 2

Kinetic Product

Answer 2

Forms products faster via the proximity effect (-78 C)

Question 3

Conjugated Dienes

Answer 3

Form the same carbocations, but the second step is faster in lower temps
- DRAW ALL RESONANCE STRUCTURES AND SELECT MOST STABLE C+ SET

Question 4

H-X

Answer 4

• adds above/below
• syn or anti
• nucleophile attacks more subbed carbon

Question 5

Regioselectivity

Answer 5

methyl < 1 < 2 < 3 ~ 1 benzyl < 2 benzyl < 3 benzyl

Question 6

H2O/CH3OH + H2SO4

Answer 6

• H3O+ = reactant
• add above or below plane
• anti or syn
• nucleophile attacks more subbed carbon

Question 7

1,2 methyl or hydride shift

Answer 7

Arrow from hydrogen bond or methyl bond points to C+ and they switch

Question 8

Br2 or Cl2

Answer 8

• Inert solvent = CH2Cl
• Anti addition (b/c of e= density from already attached halogen)
  -After brominium+/chloronium+ ion adds, other Br-/Cl- attacks either side
• no C+

Question 9

Br2 + H2O/CH3OH

Answer 9

• Bromonium/chloronium ion adds normally
• H2O or CH3OH attacks more substituted side
• Anti
• alcohol/ether on more electrophilic spot
• no C+

Question 10

1. BH3/THF 2. HO-, H2O2, H2O

Answer 10

• Concerted first step (2 step rxn)
• Syn
• no rearrangements!
• Alkene attacks boron and B-H bond back attacks more substituted carbon
• BH2 attacks
• Anti Markovnikov (OH adds to least substituted side)

Question 11

mCPBA (Epoxidation)

Answer 11

• Concerted reaction = syn
• Put oxygen’s on wedges/dashes to make it easier to determine R/S
• Add stereochemistry to alkene’s (determine cis/trans or E/X) prior to reaction

Question 12

)3 (Ozonolysis)

Answer 12

• Cleave double bonds and add ) at the end of cleaves, then add H’s at each carbon if needed to complete octet
• Can form ketones or aldehydes

Question 13

H2/PdC

Answer 13

• Syn addition

Question 14

Alkyne Hydration (H2O + H2SO4)

Answer 14

• Keto-enol tautomerization because ketone is more thermodynamically favored
• After alcohol forms, H#O+ attacks alkene and C+ forms are alcohol-connected carbon
• LP’s from oxygen form double bond at C+ leaving OH+
• H2O grabs the hydrogen from OH+ and becomes ketone

Question 15

Alkyne + Excess BR2

Answer 15

• Reacts the same way forming bromonium ion on the double bond and other Br- coming in and attacking
• Another Br2 comes in and attacks the double bond and forms bromonium ion on single bond
• No AC’s because 2 bromines on one carbon

Question 16

Alkyne + Excess HCl

Answer 16

• First the HCl reacts like it would an alkene
• Then another HCl reacts with the alkene and Cl- attaches to the carbon already connected to the chlorine due to being more stabilized w resonance or e- density some shit
• No AC’s because same thing added twice

Question 17

Conjugated Diene + Br2

Answer 17

If no temp is given, form both 1,2 and 1,4 products