Electrophilic addition to alkenes

Bromination of Alkenes

• Reagents: Br₂

• Products: 2 Br groups

• Regioselectivity: None

• Stereoselectivity: Trans addition

Oxidation of Alkenes to Form Epoxide Groups

• Reagents: Sources of oxygen, commonly m-CPBA

• Products: 1 epoxide group

• Regioselectivity: None

• Stereoselectivity: None

Hydrobromination

• Reagents: HBr

• Products: 1 Br and 1 H groups

• Regioselectivity: Markovnikov’s rule for Br group and the possibility of hydride shift

• Stereoselectivity: Usually None

Hydrochlorination

• Reagents: HCl

• Products: 1 Cl and 1 H groups

• Regioselectivity: Markovnikov’s rule for Cl group and the possibility of hydride shift

• Stereoselectivity: Usually None

Formation of Bromohydrin

• Reagents: Br₂ / H₂O

• Products: 1 OH and 1 Br groups

• Regioselectivity: Markovnikov’s rule for OH group

• Stereoselectivity: Trans addition

Addition of Alcohol to Alkenes (Markovnikov)

• Reagents: H₂O / Acid

• Products: 1 OH and 1 H groups

• Regioselectivity: Markovnikov’s rule for OH group

• Stereoselectivity: Usually none

Hydroboration

• Reagents: 1) BH₃ 2) H₂O₂ / NaOH

• Products: 1 OH and 1 H group

• Regioselectivity: Anti-markovnikov’s rule for OH group

• Stereoselectivity: Usually none

Dihydroxylation (trans)

• Reagents: 1) m-CPBA 2) H₂O / Acid

• Products: 2 OH groups

• Regioselectivity: None

• Stereoselectivity: Trans addition

Dihydroxylation (cis)

• Reagents: 1) OsO₄ 2) H₂O

• Products: 2 OH groups

• Regioselectivity: None

• Stereoselectivity: Cis addition

Oxidative Cleavage of Alkenes (using OsO₄)

• Reagents: 1) OsO₄ 2) NaIO₄

• Products: 2 RCOH groups

• Regioselectivity: None

• Stereoselectivity: None

Oxidative Cleavage of Alkenes (using O₃)

• Reagents: 1) O₃ 2) X

• Products: Depends on X

  • If X is Me₂S then RCOH

  • If X is H₂O₂ then RCOOH

  • If X is NaBH₄ then RCH₂OH

• Regioselectivity: None

• Stereoselectivity: None