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Synlett 2006(1): 0069-0072  
DOI: 10.1055/s-2005-922775
LETTER
© Georg Thieme Verlag Stuttgart · New York

Oxidation of Alcohols with Nitroxyl Radical Resins under Two-Phase Conditions

Yoshitomo Kashiwagi*a, Hiroshi Ikezoeb, Tetsuya Onob
a School of Pharmaceutical Sciences, Ohu University, 31-1 Misumido, Tomita-machi, Koriyama, Fukushima 963-8611, Japan
Fax: +81(24)9329138; e-Mail: y-kashiwagi@pha.ohu-u.ac.jp;
b Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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Publication History

Received 13 October 2005
Publication Date:
16 December 2005 (online)

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Abstract

The oxidation of alcohols to carbonyl compounds such as aldehydes and ketones was studied using potassium hexacyano­ferrate(III) mediated by nitroxyl radical polystyrene resins as catalyst under organic-aqueous two-phase conditions. Primary alcohols are readily oxidized to the corresponding aldehydes in excellent yield with no overoxidation to carboxylic acids. Secondary alcohols are converted to the corresponding ketones with a much lower efficiency. Oxidative cyclization of 1,4- and 1,5-diols to γ- and δ-lactones, respectively, proceeded nicely.

Key words

nitroxyl radical resin - potassium hexacyanoferrate(III) - alcohol - oxidation - two-phase conditions

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During the oxidation reaction, some of the polymer beads were removed from the reaction solution and extracted. The product was identified by comparing its retention time on HLPC or/and GC with those of an authentic sample. HPLC analysis was carried out using Daicel CHIRALCEL® OD column (46 mm × 250 mm). The column temperature was kept constant at 40 °C. The analytes were eluted by i-PrOH-n-hexane (2:33) at 0.7 mL min-1 flow rate, and detected by UV adsorption at 254 nm. The GC analysis was carried out using CP-Cyclodextrin-B-2,3,6-M-19 capillary column (0.25 mm × 25 m). The column temperature increased at 3 °C min-1 from 80 °C to 150 °C. The injection and detector temperatures were kept constant at 200 °C and 240 °C, respectively.