Ochem reactions - Unit 4

HX (Hydrohalogenation)

• HX (HCl, HI, HBr) added to alkene

• Markovnikov - X goes to more sub. Carbon

HX, ROOR (hydrohalogenation)

• HX (HCl, HI, HBr) added to alkene

• Anti-Markovnikov - X goes to less sub. Carbon

Dilute H2SO4 - Acid Catalyzed Hydration

• Addition of OH and H across an alkene

• Markovnikov - OH on more substituted

• racemic mixture if chiral center

• P A D - Protonate, Attack, Deprotonate

1. Hg(OAc)2, H20

2. NaBH4

Oxymercuration - Demercuration

• OH added to more sub. carbon

• no mechanism

• anti addition

1. BH3 * THF

2. H2O2, NaOH

Hydroboration-Oxidation

• H and OH added to alkene

• Anti Mark. - OH added to less substituted carbon

• syn addition - both OH and H on same type of bond (wedge-wedge, dash-dash)

Catalytic Hydrogenation - H2, Pt (Pd or Ni)

Alkene turns into alkane

• syn addition - both H on same type of bond

Epoxidation - MCPBA/PAA

Alkene turns into 3 membered addition of Oxygen

Anti Dihydroxylation

1. MCPBA or PAA

2. H30+ or H2SO4

• do mcpba or paa first to get epoxide

• then use P A D to get OH across alkene

• anti - one OH on wedge, other on dash

• no mark. or anti mark.

Ozonolysis

1. O3

2. DMS

• cleaves alkene and puts oxygen across

Hydrogenation of Alkynes

• 1 eq/xs HCl (HX)

• 1 eq HCl makes alkyne into alkene and adds a Cl to more sub. carbon

• xs HCl makes alkane and adds to Cl

Halogenation and Halohydrin Formation Reaction

1. Br2

2. H2O

• OH and Br added to alkene

• Markovnikov - OH on more sub. C

• Anti Addition