Oxidations at Unfunctionalized Carbon Atoms

Perhaps the most familiar and useful hydrocarbon oxidation is the oxidation, of aromatic side chains. Two factors enter into making this a high-yield procedure despite the use of powerful oxidants First, the benzylic site is activated to oxidation. Either radical or carbonium intermediates can be especially easily formed here because of the potential resonance stabilization. Second, the aromatic ring is inert to attack by the Mn(VII) and Cr(VI) oxidants that attack the alkyl side chain. 

It has been difficult to formulate detailed reaction mechanisms for these 

Other-successful selective oxidations of hydrocarbons by Cr(VI) reagents have been reported—for example, the oxidation of cis-decalin to the corresponding alcohol—but careful attention to reaction conditions is required, and even then there are few hydrocarbons that have been reported to give high yields of oxidation products. 

Lead tetraacetate effects oxidations at unfunctionalized C-H bonds, but this process intimately involves a functional group (hydroxyl) elsewhere in the 

The preferred transition state for this type of abstraction is six-centered, so the major products are tetrahydrofuran derivatives. Smaller amounts of six-membered ring ethers are also often encountered. 

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