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Synlett 2006(13): 2055-2058  
DOI: 10.1055/s-2006-948181
LETTER
© Georg Thieme Verlag Stuttgart · New York

Yb(OTf)3-Catalyzed Oxidation of Alcohols with Iodosylbenzene Mediated by TEMPO

Jean-Michel Vatèle*
Université Claude Bernard, ESCPE, Laboratoire de Chimie Organique 1, UMR 5181 CNRS, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne, France
Fax: +33(4)72431214; e-Mail: vatele@univ-lyon1.fr;
Further Information

Publication History

Received 28 March 2006
Publication Date:
09 August 2006 (online)

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Abstract

A rapid oxidation of primary and secondary alcohols ­using catalytic amounts of TEMPO and Yb(OTf)3 in combination with a stoichiometric amount of iodosylbenzene (PhIO) is described. This procedure operates at room temperature or above to afford carbonyl compounds in excellent yields without over-oxidation to carboxylic acids. Oxidation of primary alcohols in the ­presence of secondary alcohols proceeded with good selectivity.

Key words

alcohols - iodosylbenzene - oxidation - TEMPO - ytterbium trifluoromethanesulfonate

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All new compounds gave satisfactory physical and analytical data.

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Oxidation of Monoalcohols (Table 2) and Diols (Table 3, entries 1, 4, and 5); General Procedure. To a stirred solution of alcohol (1 mmol) in CH2Cl2 (4 mL) were added TEMPO (8 mg, 5 mol%) and PhIO (286 mg, 1.3 equiv). The suspension was cooled to 0 °C and Yb(OTf)3 (12.5 mg, 2 mol%) was added. The reaction mixture was stirred at 0 °C or r.t. depending on the substrate until the alcohol was no longer detectable by TLC (the reaction mixture became almost limpid). The yellow slightly cloudy solution was poured onto a column of silica gel (10 g) and eluted with Et2O-PE. The purity of each aldehyde or ketone was checked by NMR spectroscopy.

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In the presence of 1.3 equivalent of PhIO, cis-1,2-cyclo-hexanedimethanol gave the γ-lactone (55% yield) and lactols (9%); 30% of the diol was recovered (as compared to Table 3, entry 2).

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Oxidative Lactonization of Diols (Table 3, entry 2); Typical Procedure. To a solution of cis-1,2-cyclo-hexanedimethanol (0.15 g, 1.04 mmol) in CH2Cl2 (5 mL) were added PhIO (0.594 g, 2.6 equiv) and TEMPO (16 mg, 0.1 equiv). The suspension was cooled to 0 °C and Yb(OTf)3·xH2O (26 mg, 0.04 equiv) was added. The reaction was stirred at r.t. for 1 h and poured onto a column of silica gel. Elution with PE-Et2O (1:1) gave cis-perhydro-phthalide (0.14 g, 96%) as an oil. 13C and 1H NMR data were identical with those described in the literature.