0:00 / 0:00

Dihydroxylation

Dihydroxylation reactions:
  1. occur in multiple steps
  2. adds two alcohols across an alkene bond to form a diol (di- for "two"; -ol for "alcohol")
  3. there is no Markovnikov or anti-Markovnikov addition since the two groups added are the same!
  4. the two alcohols are are added syn (on the same side) for stereochemical outcome


PAGE BREAK

Steps of a dihydroxylation:

  1. a concerted reaction (occurs in a single step) where a 5-membered metallocycle is formed using the OsO4 or KMnO4.
  2. hydrolysis with a dilute base gives the diol


Wize Tip
The mechanism of dihydroxylation is complicated and you do not need to know it!


Watch Out!
These reactions are stereospecific which means they maintain the geometry of the reagent. This means that cis double bonds stay cis and trans double bonds stay trans.


Example: predict the product of the following ozonolysis reactions.



0:00 / 0:00

Example: Dihydroxylatoin


Provide the product(s) of the following dihydroxylation reactions.