|Chapter 17: Aldehydes and Ketones. Nucleophilic Addition to C=O|
Oxidation of Primary
and Secondary Alcohols
(review of Chapter 15)
If you see Cr reagents, you are probably looking at an oxidation reaction of a alcohol or an aldehyde.
|1o alcohol aldehyde|
|2o alcohol ketone|
Cr OXIDATION OF ALCOHOLS
|The mechanism is not trivial,
so attention here is focussed on the actual oxidation step. Prior to this,
the alcohol reacts to form a chromate ester (shown). A base (here
a water molecule) abstracts a proton from the chromate ester, the C=O forms and a Cr species leaves.
This demonstrates the importance of the carbinol H to this mechanism.
|© Dr. Ian Hunt, Department of Chemistry, University of Calgary|