OCHEM CHAPTER 8 REACTIONZ

reagents stereospecificity regioselectivity products

Hydrohalogenation

Reagents: HX

X = Cl, Br, I

Carbocation intermediate - possible rearrangement

R: Mark

Product: Alkyl halide

Hydrobromination w/ peroxides

Reagents: HBr, ROOR

Only addition exception

R: Anti-mark

Only for Br

Product: Alkyl Halide

Acid-Catalyzed hydration

Reagent: H3O+ (same as H2SO4, H2O)

Carbocation intermediate - possible rearrangement

R: Mark

Product: Alcohol

Modified Acid-Catalyzed hydration (ether)

Reagents: HOR, H+ (H2SO4)

Carbocation intermediate - possible rearrangement

R: Mark

Product: Ether

Oxymercuration - Demercuration

Reagents: 1)Hg(OAc)2, H2O 2)NaBH4

No rearrangement

R: Mark

Product: alcohol

Modified Oxymercuration - Demercuration

Reagents:1)Hg(OAc)2, HOR 2)NaBH4

No rearrangement

R: Mark

Product: Ether

Halogenation

Reagents: X2, CCl4

X = Br or Cl

CCl4 non participating, CH2Cl2 can also be used

R: Mark

S: Anti

Product: Vicinal dihalide (attached to neighboring carbons)

Halohydrin Formation

Reagents: X2, H2O

X = Br or Cl

R: Mark

S: Anti

Product: Halohydrin (Alcohol and alkyl halide)

OH forms on Mark side (more subbed)

Haloether Formation

Reagents: X2, HOR

X = Br or Cl

R: Mark

S: Anti

Product: Haloether

Ether forms on Mark side

Hydroboration - Oxidation

Reagents: 1) BH3, THF 2) H2O2, HO-

BH3 can also be R2BH or 9-BBN (BAM)

R: Anti-Mark

S: Syn

Product: Alcohol

Syn Dihydroxylation

Reagents: 1)OsO4, pyr 2)NaHSO3, H2O

Alt recipes: OsO4, NMO / OsO4, tBuOOH / KMnO4, NaOH, cold

S: Syn

Product: Syn diol

Epoxide formation via peroxyacid

Reagents: RCO3H

Alt recipe: mCPBA

S: Syn

Product: Epoxide

Epoxide formation via halohydrin

Reagent: 1) X2, H2O 2) NaOH

Alt recipe: step 2 can be any strong base

S: Syn

Product: Epoxide

Anti Dihydroxylation

Reagents: 1) RCO3H 2) H3O+

Step 1 makes the epoxide step 2 opens it

S: Anti

Product: Trans diol

Catalytic Hydrogenation

Reagents: H2, Pt

Alt recipes: Pt can also be Ni, Pd, Pd/C

S: Syn

Product: Alkane

Will not reduct C=C in arene

Ozonolysis

Reagents: 1) O3 2) Zn, H+ or (CH3)2S

Product: Depends on number of H attached to C

0H: Ketone

1H: Aldehyde

2H: Formaldehyde