Oxidation of Alkynes
Reaction type: Electrophilic Addition
||Chapter 9: Alkynes
- Alkynes can also be hydrated to form enols that immediately
- Terminal alkynes give aldehydes, internal alkynes give ketones
- Typical reagents (two steps) 1. BH3 or B2H6 then 2) H2O2 / NaOH
- Electrophile : B atom
- Regioselectivity : Anti-Markovnikov, since the
B is ultimately converted to the -OH.
MECHANISM FOR HYDROBORATION OF ALKYNES
Mechanistically analgous to the hydroboration of alkenes to form the enol.
The resulting enol tautomerises to the aldehyde or ketone.