CHEM207 Exam 3

Alkene Hydrohalegonation REAGENTS

HX

Alkene Hydrohalegonation

• markovnikov X addition

• enant

Radical Alkene HBr Addition

HBr, peroxides

• anti-markovnikov

• Initiation, propagation, termination

• enant

Alkene Hydroboration-oxidation REAGENTS

1) BH3, THF 2) H2O2, -OH

Alkene Hydroboration-oxidation

• syn addition of H and BH2

• less sub OH

• enant

Alkene Oxymercuration REAGENTS

1) Hg(OAc)2, H2O 2) NaBH4, -OH

Alkene Oxymercuration

• more sub OH

• backside attack of H2O breaks ring

• no mechanism for step 2

• enant

Alkene Halogenation REAGENTS

X2

Alkene Halogenation

• anti addition of Xs

• backside attack with X- breaks ring

• enant

Halohydrin REAGENTS

X2, H2O/MeOH/RSH

Halohydrin

• anti X, OH addition

• backside attack of nuke

• enant

Oxidation with peroxycarboxylic acids REAGENTS

1) mCPBA 2) trace acid

mCBPA

Oxidation with peroxycarboxylic acid

• on more sub alkene

• trans glycol

• epoxied after step 1

• nuke—>more sub C

• enant

Syn-dihydroxylation REAGENTS

1) OsO4 2) H2O

Syn-dihydroxylation

• cis glycol

• no mechanism for hydrolysis

• enant

Ozonolysis REAGENTS

1) O3 2) Me2S (red) / H2O2, H2O (ox)

Ozonolysis

• red: aldehydes/ ketones

• ox: carboxylic acids/ ketones

2X on alkane —> R=_H

1) NaNH2 (excess), NH3 (l)

2) H3O+

• E2

R=_H —> R=_: (-)

NaNH2, NH3 (l) / NaH / THF

Sia2BH