alkenes/alkynes + free radicals

Hydrogenation of alkenes

alkene + H2 --> alkane

carbocation formation? no

rearrangement? no

regiochem? no

stereochem? syn addition

Hydrogenation of alkynes

alkyne + H2 --> alkane

carbocation formation? no

rearrangement? no

regiochem? no

stereochem? no

Electrophilic addition (HBr, HCl, HI)

alkene to haloalkane

carbocation formation? yes

rearrangement? yes

regiochem? yes

stereochem? no

Alkynes Electrophilic addition (HBr, HCl, HI)

alkyne to haloalkane

carbocation formation? yes

rearrangement? no

regiochem? yes

stereochem? no

Halogenation (Cl2, Br2)

carbocation formation? no

rearrangement? no

regiochem? no

stereochem? anti addition

Alkyne Halogenation (Cl2, Br2)

carbocation formation? no

rearrangement? no

regiochem? no

stereochem? anti addition IF 1 eq. if not then no

Hydration of alkenes

+ H20, conc. H2SO4 or H2PO4, turns into alcohol

carbocation formation? yes

rearrangement? yes

regiochem? yes (markovnikov)

stereochem? no

Hydration of alkynes

+ H20, conc. H2SO4 or H2PO4, turns into an aldehyde if terminal and ketone if internal

carbocation formation? yes

rearrangement? Tautomerization

regiochem? yes (markovnikov)

stereochem? no

Oxymercuration alkenes

1) Hg(OAc)2, H2O

2) NaBH4

forms:

carbocation formation? no

rearrangement? no

regiochem? markovnikov

stereochem? anti at first with Hg(OAc) but then none

Hydroboration alkynes

BH3, THF, H2O2, OH- (internal)

(sia)BH2, H2O2 (terminal)

forms: turns into an aldehyde if terminal and a ketone if internal

carbocation? no

rearrangement? no

regiochem? anti-markovnikov

stereochem? syn addition

Halohydrin Formation of Alkenes

X2, H2O/ROH -> X OH/OR

forms: 1 Cl or Br with an OH/OR

carbocation? no

rearrangement? no

stereochem? anti

regiochem? markovnikov

Hydroboration alkenes

BH3, THF, H2O2, OH-

forms: alcohol (OH)

carbocation? no

rearrangement? no

regiochem? anti-markovnikov

stereochem? syn addition

Free Radical Halogenation HBr (alkene)

HBr, H2O2 or light/heat

forms: alkyl bromide

carbocation? no

rearrangement? no

regiochem? anti-markovnikov

stereochem? none

Free Radical Halogenation (alkane)

Cl2 or Br2 with light or heat

forms: alkyl halide

carbocation? no

rearrangement? no

regiochem?- usually

markovnikov for Br2 (MSS) and anti-markovnikov (LSS) for Cl2

stereochem? none