List of oxidants that can possibly abstract protons from an SP3 hybridized carbon of cycloalkanes?
First answer:
Aqueous alkaline OsO4 at 85oC oxidises saturated alkanes, including primary, secondary , and tertiary C-H bonds. see Ref below: J. Org. Chem., 1975, 40 (17), pp 2539–2540 DOI: 10.1021/jo00905a029 Publication Date: August 1975.
2nd answer:
Oxidation of hydrocarbons. VI. Oxidation of cycloalkanes by ruthenium tetroxide. Ref: J. Org. Chem., 1975, 40 (17), pp 2539–2540, DOI: 10.1021/jo00905a029.
Third answer:
Using peroxides such as dicumyl peroxide, has opened up the chemistry to some extent, allowing for example the introduction of a phenylamino group.