Page 107 - Pharm.Org.Chem-I 02-06-05-101

C) Oxidative cleavage

There are many reagents that will add across an alkene and completely cleave the C=C
bond to give carbonyl compounds. We will explore two such reactions,

❖ Ozonolysis

E.g.1

Because hydrogen peroxide is a byproduct of ozonide hydrolysis and has the potential to
oxidize the products, the second half of this two-stage ozonolysis sequence is carried out in
the presence of a reducing agent, usually zinc.

E.g.2

❖Heating with hot basic KMnO4
Treatment with hot basic potassium permanganate oxidatively
cleaves the double bond of an alkene.
▪ Alkenes with monosubstituted carbon atoms are oxidatively

cleaved to salts of carboxylic acids.

▪ Disubstituted alkene carbons are oxidatively cleaved to
ketones.

▪ Unsubstituted alkene carbons are oxidized to carbon
dioxide.

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