Iodine-Pyridinium chlorochromate

On the contrary, the pyridinium chlorochromate-iodine system which is a very effective oxidant of silylenol ethers failed with enamines66. 

In order to remove the primary hydroxy group, the protected triol 24 was acet-ylated and treated with pyridinium tosylate to yield the monoester 25. Selective tosylation of the primary hydroxy group followed by Finkelstein exchange for iodine yielded the iodo derivative 26 which was transformed into the protected cyclohexene diol 27 by reductive removal of the iodine with tributyltin hydride followed by protection of the tertiary hydroxy group with dihydopyran. After removal of the benzoyl group by alkaline saponification the resulting allylic alcohol was oxidised to the desired enone 28 with pyridinium chlorochromate in buffered solution (ref. 16). 

Reductive Silylation ofp-Qninones. Me6Si2 in combination with a catalytic amount of iodine converts /7-quinones (30) into l,4-bis(trimethylsiloxy)arenes (31) in almost quantitative yields (eq 15). The products are a protected form of quinones, which are regenerated by oxidation with pyridinium chlorochromate (PCC)P... 

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