Cleavage, oxidative superacidic

When the dry ozonation technique is employed (dry silica gel with a preadsorbed organic substrate is saturated with ozone at -78°C then warmed up to room temperature), ozone exhibits an enhanced reactivity, presumably due to the slightly acidic nature of silica gel. Regioselectivities and stereoselectivities under these conditions are very similar to those in superacidic liquid-phase ozonation. Straight-chain alkanes are oxidized at the secondary carbon to yield a mixture of alcohols and ketones, Branched acyclic alkanes give tertiary alcohols and yield ketones via C-C bond cleavage, Insertion of ozone into the C-H and C-C a bonds was evoked to account for the observations (Scheme 6.27). 

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