Summary of Alkene reactions

Hydrohalogenation reagents

HX (HCl, HBr, HI)

Product of Hydrohalogenation

Add H and X

Regiochemistry of Hydrohalogenation

Markovnikov (H adds to the more substituted carbon)

Stereochemistry of hydrohalogenation

Typically leads to a racemic mixture due to the formation of a planar carbocation.

Radical Addition of HBr reagents

HBr, ROOR

Product of Radical Addition of HBr

Add H and Br

Regiochemistry of Radical Addition of HBr

anti-Markovnikov (H adds to least substituted)

Stereochemistry of Radical Addition of HBr

mixed

Reagents of Acid-Catalyzed Hydration

H3O+ (dilute H2SO4)

Product of Acid-Catalyzed Hydration

Add H and OH

Regiochemistry of Acid-Catalyzed Hydration

Markovnikov

Stereochemistry of Acid-Catalyzed Hydration

Mixed

Reagents of Oxymercuration-Demercuration

1) Hg(OAc)2, H2O

2) NaBH4

Product of Oxymercuration-Demercuration

Add H and OH

Regiochemistry of Oxymercuration-Demercuration

anti-Markovnikov

Stereochemistry of Oxymercuration-Demercuration

Syn

Reagents of Hydroboration-Oxidation

1) BH3, THF

2) H2O2, NaOH

Product of Hydroboration-Oxidation

Add H and OH

Regiochemistry of Hydroboration-Oxidation

anti-Markovnikov

Stereochemistry of Hydroboration-Oxidation

Syn

Reagents of Catalytic Hydrogenation

H2, Pt

Product of Catalytic Hydrogenation

Add H and H

Regiochemistry of Catalytic Hydrogenation

N/A because both are H

Stereochemistry of Catalytic Hydrogenation

Syn

Reagents of Bromination (or chlorination)

B2 (or Cl2)

Product of Bromination (or chlorination)

Add Br and Br (or Cl and Cl)

Regiochemistry of Bromination (or chlorination)

N/A

Stereochemistry of Bromination (or chlorination)

anti

Reagents of Halohydrin formation

Br2, H2O

Product of Halohydrin formation

Add Br and OH

Regiochemistry of Halohydrin formation

OH to more substituted

Stereochemistry of Halohydrin formation

Anti

Reagents of Syn Dihydroxylation

KMnO4, or OsO4/NMO

Product of Syn Dihydroxylation

Add OH and OH

Regiochemistry of Syn Dihydroxylation

N/A

Stereochemistry of Syn Dihydroxylation

Syn

Reagents of Epoxidation

RCO3H (e.g., MCPBA)

Product of Epoxidation

Form epoxide

Regiochemistry of Epoxidation

N/A

Stereochemistry of Epoxidation

adds to one face

Reagents of Anti-dihydroxylation

1) RCO3H

2) H3O+

Product of Anti Dihydroxylation

Add OH and OH

Regiochemistry of Anti Dihydroxylation

N/A

Stereochemistry of Anti Dihydroxylation

Anti

Reagents of Ozonolysis

1) O3

2) DMS or Zn/H2O

Product of Ozonolysis

Cleave C=C, form two C=O groups

regiochemistry of Ozonolysis

N/A

Stereochemistry of Ozonolysis

N/A

Zaitsev’s rule

most stable alkene is major product, has two substituents, trans > cis

Zaitsev’s used when

elimination reactions (E1, E2) EXCEPT BBB and non-antiperiplanar B Hydrogens on ring

Hofmann’s

in elimination reaction (usually E2) w BBB, less substituted alkene is major product

Hofmann’s used when

when forming alkene from amine, when steric hindrance or poor bulky LG forces base to take B hydrogen from least hindered carbon (E rxns)