(selective oxidation of secondary alcohols)
Physical Data: see Cerium(IV) Ammonium Nitrate.
Form Supplied in: Nafion 511 is supplied as white granules 1 mm in diameter; Nafion® is a registered trademark of E. I. du Pont de Nemours & Co.
Preparative Methods: Nafion 511 (1.1 g) is stirred with a solution of (NH4)2Ce(NO3)6 (1.75 g) in 30 mL of deionized water for 36 h at 25 °C. The catalyst (cerium(IV)-Nafion 511, Ce/NAFK) is filtered, washed with water (10 mL × 5) and dried to constant weight. Titration of the polymer indicates capacity of 0.54 mmol of CeIV per gram, which corresponds to 71% of the theoretical capacity of a fully loaded resin (1).
Oxidation of Alcohols.
t-Butyl Hydroperoxide can oxidize alcohols to carbonyl compounds in the presence of a polymer supported catalyst (Ce/NAKF).1 In contrast to the Cerium(IV) Ammonium Nitrate-Sodium Bromate system, this method is not affected by the presence of carbon-carbon double bonds in the substrates. Thus 2-cyclododecen-1-ol and 11-dodecen-2-ol give the corresponding ketones in good yields (eq 1). Selective oxidation of secondary hydroxyls in the presence of primary ones has also been achieved (eqs 2 and 3). These reactions are performed with Sodium Bromate as a co-oxidant in AcOH at 55 °C. The catalyst is easily recovered and reused without loss of CeIV ion.
- 1. (a) Kanemoto, S.; Saimoto, H.; Oshima, K.; Nozaki, H. TL 1984, 25, 3317. (b) Kanemoto, S.; Saimoto, H.; Oshima, K.; Utimoto, K.; Nozaki, H. BCJ 1989, 62, 519.
Kyoto University, Japan
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