addition reactions + reagents

hydrohalogenation

• H — X

• markovnikov regioselectivity

• possible chiral center

• possible rearrangement (methyl or hydride shift)

hydrohalogenation w/ peroxides

• H — X and ROOR

• anti markovnikov regioselectivity

acid- catalyzed hydration

• H — OH

• sulfuric acid (H2SO4 + H2O) or H3O+

• markovnikov regioselectivity

• new chiral center formed = racemic mixture

• dilute H2SO4 with more H2O = breaking pi bond (hydration)

• conc. H2SO4 with no water = forming pi bond (dehydration)

oxymercuration - demercuration

• 1). Hg(OAc)2 , H2O 2). NaBH4

• markovnikov regioselectivity

• no rearrangements

hydroboration - oxidation

• 1). BH3 - THF 2). H2O2, NaOH

• anti markovnikov regioselectivity

• stereospecific - syn: cis products

• if there’s a chiral center, there are enantiomers

catalytic hydrogenation

• addition of H2 across a c=c double bond

• metal catalyst (H2 with pt, pd)

• alkene turns into alkane

• stereospecific - only syn

• possible meso compound

• wilkerson’s catalyst

halogenation

• Cl2 or Br2

• stereoselective - only anti addition

halohydrin formation

• Br2 or Cl2 with water

• halide goes on less sub. carbon

• OH goes on more sub. carbon

• regioselective

anti dihydroxylation

• addition of OH and OH across the pi bond

• peroxide - RCO3H and MCPBA with H3O

• forms an epoxide first then a diol

syn dihydroxylation

• adds OH and OH across pi bond

• syn addition

• OsO4 then Na2SO3 / H2O

oxidative cleavage

• breaks up an alkene into a ketone and aldehyde

• O3 with DMS or Zn/H2O