H 2 CCH 2 KMnO (^4) OH−, Η 2 2
2 O
HCCH
OH
- cold
OH
Ethene 1,2-Ethanediol
(ethylene glycol)
CH 3 CH CH (^2) 2. Na
2 SO 3 /H 2 O or^ NaHSO
- OsO 4 , pyridine CH 3 CH CH 2
3 /H 2 O OHOH
Propene 1,2-Propaneiol
(propylene glycol)
8.10A MECHANISMS FOR SYN-HYDROXYLATION OF ALKENES
- The mechanism for the syn-hydroxylation of alkenes:
CC CC OH
−
O
Mn
O
O O−
2
several
steps
+ OHOH
Mn
O O
HO CC + MnO^2
O O−
CCpyridine CC
O
Os
Os O
O
O
O
An osmat
O
O
NaHSO 3
H 2 O CC
OHOH
+ Os
+
O e ester
+ MnO 4 −
OH−
cold
cis-1,2-Cyclopentanediol
H H
HH
O O−
H 2 O HH
(a meso compound)
O
Mn
O HO OH