reaction mechanisms

Hydroboration

• 2-step anit-markovnikov addition of an OH

• BH₃ / NaOH, H₂0, H₂O₂

• Concerted mechanism

• Regiochemistry dictated by sterics of transition state

• + enantiomer

• syn-stereochemistry (substituents are on the same side of the molecule)

Strong Acid addition

• markovnikov addition of an OH

• H₂SO₄ / H₂0

• carbocation intermediate

• hydride shift

Dihalogen reaction

• X₂ reacts with an alkene to form this

• + enantiomer

• anti-stereochemistry (substituents are on opposite sides of the molecule)

Halohydrin formation

• solvent adds to the alkene carbon that would form the more stable carbocation

Epoxidation (stereochemistry + regiochemistry)

• requires an alkene and peroxy acid

• mCPBA is most common

ozonolysis- reductive workup

• H appears

• ketone / aldehyde formation

• O₃ / Zn or DMS

ozonolysis- oxidative workup

• OH stays

• ketone / carboxylic acid formation

• O₃ / NaOh, H20, H2O2

Hydrogenation

• addition of 2 Hydrogen atoms

• H2, Pd/C

dihydroxylation

• the syn addition of 2 OH groups across a double bond

• OsO₄

oxymercuration- reduction 

• another way to get Markovnikov addition of an OR group

• Hg(OAc)₂, H20 / NaBH₄