These are oxidation reactions which also involve the cleavage of carbon-carbon bonds, with the oxidation occurring at both ends. Some will involve complete separation of 2 oxidised fragments and others will leave them connected together.

Cleavage of Single Bonds

i. 1,2-diols with Lead Tetra-acetate

This reaction can also be carried out with NaIO4 instead of Pb(OAc)4.

ii. Ketones – the Baeyer Villiger Reaction

NB. The most substituted carbon will migrate in the third step (here tertiary is more substituted than phenyl).

Cleavage of Double Bonds

i. Ozonolysis: (see the relevant electrophilic addition page)
Most of this reaction is covered in the aforementioned electrophilic addition page, but not the usual conclusion. From the secondary ozonide (labelled below), a reducing agent is usually used to isolate ketones as the products – for example, with SMe2;