I'm currently writing a report about the oxidations of various alcohols using different catalytic systems. In all papers it is stated that benzylic and allylic alcohols are "activated", while aliphatic ones are not.
What exactly does this mean?
Why is it usually much easier to oxidise a benzylic alcohol rather than an aliphatic one? What effect does the benzene ring have on the O-H? How does pKa and bond strength come in to play?