Solventless Rearrangement Promoted by MW Irradiation

Limitations in the use of potassium permanganate and similar oxidizing agents [102-104] have already been mentioned in Section 2.2.2.4. The immobihzation of metallic reagents on solid supports has addressed some of these Hmitations and 

The use of chromium(VI) reagents as oxidants is limited by their inherent toxicity, the need to prepare them in various complex forms (with acetic acid or pyridine), and complicated work-up procedures. Chromium trioxide (Cr03) immobilized on pre-moistened alumina affords efficient oxidation of benzyl alcohols to carbonyl compounds by simple mixing. Remarkably, neither the over-oxidation to carboxylic acids nor the usual formation of tar, a typical occurrence in many CrOj oxidations, is observed [108]. The reagent system is also used for the preparation of acyclic a-nitro ketones by the oxidation of nitroalkanols under solvent-free conditions [109] 

The solid oxidizing reagent IBD-alumina has also been used for the rapid, high-yielding, and selective oxidation of alkyl, aryl, and cyclic sulfides to the corresponding sulfoxides upon MW irradiation [117]. 

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