Oxidations with Immobilized Periodinanes

In recent years hypervalent iodine compounds have experienced extensive investigations yielding many results of practical synthetic importance. Supported iodi-nanes, i.e. iodoso or iodine(III) reagents, have been prepared by several groups, mainly as the bis-acetoxyiodoso derivatives [15-18] or as the respective dihalogeno compounds [19]. Iodoso reagents are employed in the oxidation of hydroquinones and phenols that have been exploited in the formation of spiroketals from a variety of tyrosines. 

In contrast, periodinanes (i.e. iodoxo or iodine(V) reagents), preferably as the 1-hydroxy-(li-f)-benzo-l,2-iodoxol-3-one-l-oxide (2-iodoxybenzoic acid, IBX) [20, 21] or its acetylation product, the Dess-Martin reagent [22], have been widely used for oxidation of sensitive and complex alcohols. Periodinanes have not yet been prepared on a polymer support a silica-supported IBX has been reported recently [23]. 

The limitations of oxoammonium resins in the oxidation of nitrogen-containing moieties prompted investigation of polymer-supported periodinanes as poten- 

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