Synlett 2005(14): 2175-2178  
DOI: 10.1055/s-2005-872259
LETTER
© Georg Thieme Verlag Stuttgart · New York

Polymer-Supported IBX-Amide Reagents: Significant Role of Spacer and Additive in Alcohol Oxidation

Woo-Jae Chung, Duk-Ki Kim, Yoon-Sik Lee*
School of Chemical & Biological Engineering, Seoul National University, Seoul 151-744, Korea
Fax: +82(2)8769625; e-Mail: yslee@snu.ac.kr;
Further Information

Publication History

Received 12 April 2005
Publication Date:
03 August 2005 (online)

Abstract

We found that the spacer and additive play a significant role in the oxidation of alkyl alcohols using polymer-supported IBX-amide reagents. The introduction of the spacer between the polymer support and IBX-amide group improved the initial conversion rate (up to 60% conversion). Furthermore, various alcohol compounds, when reacted with IBX-amide resin in the presence of BF3·OEt2, were effectively converted into the corresponding aldehydes or ketones within 5-30 minutes in high purities (>94%) at room temperature.

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Swelling volume was determined using a column (ID 0.9 cm, length 40 cm) with sintered glass filter. Each resin (500 mg) was swollen in CHCl3 for 2 h. Thereafter, the solvent was removed by filtration, and the swelling volume of each resin was determined as: resin 1 (4.2 mL/g); resin 2 (3.9 mL/g); resin 3 (3.4 mL/g); resin 4 (3.8 mL/g).

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Oxidation of 1-decanol (1 equiv) was performed using IBX-amide resin 1 (1.3 equiv) with N-methyl hexanamide (1.3 equiv) in CHCl3 at r.t. The reaction mixture was analyzed by GC-MS after 3 h and 6 h. The conversion of 1-decanol was compared with that from the oxidation of 1-decanol without N-methyl hexanamide (NMH) under the same condition; 37% (with NMH) and 34% (without NMH) after 3 h, 43% (with NMH) and 44% (without NMH) after 6 h. No reaction between NMH and IBX-amide resin 1 was detected.

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Three cycles of oxidations with the condition employed in entry 1 (in Table [1] ) and reactivations were investigated. The oxidation capacity was maintained in the range of 0.55-0.59 mmol/g. The conversions of 1-decanol were determined as >97 (run 1), >97 (run 2), and 95% (run 3).