Alkene Reactions

H2, Pt

Halogenation: Syn addition of two H

HX

(X = Cl, Br)

Hydrohalogenation (Markovnikov)

Halide added markovnikov (most substituted)

Halide and H are added syn

HBr, ROOR

Hydrohalogenation (anti-markovnikov)

Halide added anti-markovnikov (least substituted)

Halide and H are added anti

X2, CCl4

(X = Halides = Cl, Br)

Halogenation

Addition of two halides across a double bond, anti

X2, H2O

(X = Cl, Br)

Halohydrin Formation

Addition of OH and halide across double bond, anti

OH added markovnikov, halide is anti

H2SO4, H2O

Acid Catalyzed Hydration

Addition of water, OH and H, across alkene, syn

OH is markovnikov, H is anti-markov

1. Hg(OAc)2, H2O

2. NaBH4

Oxymercuration-Demercuration

Addition of H and OH across alkene, anti

OH is markovnikov, H is anti

1. Hg(OAc)2, ROH

2. NaBH4

Alkoxymercuration-Demercuration

Addition of ester and H, anti

Ester is markovnikov, H is anti-markov

1. BH3,THF

2. H2O2, NaOH, H2O

Hydroboration-Oxidation

Addition of water, OH and H, across alkene, anti

OH is added anti-markov, H is markov

MCPBA

Epoxidation

Formation of an epoxide

OsO4 OR KMnO4, cold

Dihydroxylation (syn)

Addition of two OH across alkene, syn

MCPBA, H3O+

Dihydroxylation (anti)

Addition of two OH across double bond, anti

KMnO4, H3O+

Oxidative Cleavage

Formation of a ketone and carboxylic acid by breaking DB

O3, (CH3)2S

Ozonolysis (aldehyde)

Break DB forming aldehyde

O3, H2O2

Ozonolysis (carboxylic acid)

Break DB forming two COOH

CH3CH2O- , CH3CH2OH

Forms an alkene that is stable

Stable = more substituted

Sodium Ethoxide is a small base and can take a H from a tertiary C

T-butox, CH3CH2OH

Forms an alkene that is unstable

Unstable = least substituted

Tert butoxide is a bulky base so it pulls a H from the ends

H2SO4

Using sulfuric acid can turn any alcohol (1º,2º3º) into an alkene