Oxygenation by Other Methods

The CCl4-HF-SbF5 system developed by Jouannetaud and co-workers and used in the selective fluorination of imines (see Section 5.10.1) can be applied in the oxygenation of ketones and carboxamides as well. The hydroxylation of ketones is selective [Eq. (5.229)], provided that a five- or six-membered cyclic carboxonium ion preventing fluorination is involved.534,659 Fluorination, however, may be a side reaction with product distributions depending on quenching conditions (aqueous Na2CC 3 or HF-pyridine). Similar features are characteristic of the transformation of carboxamides.659 

Adamantane can be transformed to 4-oxahomoadamantane in good yields by bis (trimethylsilyl)peroxide664 and sodium percarbonate665 in the presence of triflic acid. Product formation is explained by C—C cr-bond insertion [Eq. (5.233)]. Diamantane is transformed into isomeric oxahomodiamantanes (C—C insertion) and bridgehead diamantanols (C—H insertion).664 

---