CH 331 (OSU-Myles) Study Guide Test
Questions Fully Solved.
Hydroboration-Oxidation of Internal Alkynes - Answer 1. BH3/THF (BH2 - electrophile, ant
Markovnikov / H - nucleophile)
2. NaOH, H2O2, H2O (break BH2 bond --> OH)
-Enol-Minor
-Ketone-Major
Unsymmetrical (BH2 attacks less hindered side)
Symmetrical (BH2 attacks either side)
Addition of HI and HBr to alkenes - Answer - Markovnikov for H+
- Multi Step
- Potential carbocation rearrangements
- Regioselectivity (3° - 1° complete regioselective)
(3° - 2° regioselective)
Acid-Catalyzed Hydration of Alkenes (H2SO4 and H2O) - Answer -H2SO4 : proton donator
-H2O : Alcohol donor
- Markovnikov (electrophile to sp2 carbon with most # of H's)
- Produce the more stable carbocation (3°>2°>1°)
- OH2 attacks carbo cation
Acid-Catalyzed + Alcohol in alkenes (H2SO4 and MeOH) - Answer - H2SO4: proton donator
- CH3OH: attacks carbocation
- Markovnikov
- Production of oxonium (proton transfer to solvent)
- Final Product: ether (R-O-R)
Hydrohalogenation to alkenes (HBr or HI) - Answer - Gives proton to markovnikov
- Potential carbocation rearrangements
- Halogen attacks carbo cation
, Halohydrin in Alkenes (Multiple Nucleophile: Cl2/Br2 and CH3OH) - Answer - Major product
includes:
--> One halogen and highest concentrated nucleophile
- Minor product includes:
--> Two halogens
Major---------------Minor
I>Br>Cl>F
Oxymercuration-reduction of Alkenes - Answer 1. Hg(OAc)2, H2O/THF
2. NaBH4
1: Hg cyclo, loss of (OAc group), H2O attacks more stable carbon, proton transfer to solvent
2: loss of Hg group and addition of H
Hydroboration Oxidation of Alkenes - Answer 1. BH3/THF
2. OH-, H2O2, H2O
1. BH2 is electrophile ----> markovnikov
2. BH2 cut off and replaced with OH
-----> Major: anti-markovnikov
Epoxidation of Alkenes - Answer MCPBA/CH2Cl2
- Syn Addition (Front and Back side attack - Cis)
- can be enantiomers, mesoachiral, identical
Dihydroxylation of Alkene - Answer - OsO4
- H2O2
Syn Addition (Cis)
Major Product: 2 OH ( one on each sp2 carbon)
Questions Fully Solved.
Hydroboration-Oxidation of Internal Alkynes - Answer 1. BH3/THF (BH2 - electrophile, ant
Markovnikov / H - nucleophile)
2. NaOH, H2O2, H2O (break BH2 bond --> OH)
-Enol-Minor
-Ketone-Major
Unsymmetrical (BH2 attacks less hindered side)
Symmetrical (BH2 attacks either side)
Addition of HI and HBr to alkenes - Answer - Markovnikov for H+
- Multi Step
- Potential carbocation rearrangements
- Regioselectivity (3° - 1° complete regioselective)
(3° - 2° regioselective)
Acid-Catalyzed Hydration of Alkenes (H2SO4 and H2O) - Answer -H2SO4 : proton donator
-H2O : Alcohol donor
- Markovnikov (electrophile to sp2 carbon with most # of H's)
- Produce the more stable carbocation (3°>2°>1°)
- OH2 attacks carbo cation
Acid-Catalyzed + Alcohol in alkenes (H2SO4 and MeOH) - Answer - H2SO4: proton donator
- CH3OH: attacks carbocation
- Markovnikov
- Production of oxonium (proton transfer to solvent)
- Final Product: ether (R-O-R)
Hydrohalogenation to alkenes (HBr or HI) - Answer - Gives proton to markovnikov
- Potential carbocation rearrangements
- Halogen attacks carbo cation
, Halohydrin in Alkenes (Multiple Nucleophile: Cl2/Br2 and CH3OH) - Answer - Major product
includes:
--> One halogen and highest concentrated nucleophile
- Minor product includes:
--> Two halogens
Major---------------Minor
I>Br>Cl>F
Oxymercuration-reduction of Alkenes - Answer 1. Hg(OAc)2, H2O/THF
2. NaBH4
1: Hg cyclo, loss of (OAc group), H2O attacks more stable carbon, proton transfer to solvent
2: loss of Hg group and addition of H
Hydroboration Oxidation of Alkenes - Answer 1. BH3/THF
2. OH-, H2O2, H2O
1. BH2 is electrophile ----> markovnikov
2. BH2 cut off and replaced with OH
-----> Major: anti-markovnikov
Epoxidation of Alkenes - Answer MCPBA/CH2Cl2
- Syn Addition (Front and Back side attack - Cis)
- can be enantiomers, mesoachiral, identical
Dihydroxylation of Alkene - Answer - OsO4
- H2O2
Syn Addition (Cis)
Major Product: 2 OH ( one on each sp2 carbon)
