Isoflavones are synthesized in an one-pot reaction by treating the hypervalent iodine(III) reagent, [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser's reagent) with 2¢-benzoyloxychalcones in MeOH. A combined use of (diacetoxyiodo)benzene (DIB)/p-toluenesulfonic acid (TsOH) is also effective for the same purpose. As an extension of these monomeric reagents, polymer-supported DIB {PSDIB, poly[4-(diacetoxy)iodo]styrene} with TsOH works also well. The merits of the latter are the ease of separation of isoflavones from the reaction mixture, no liberation of PhI, and reuse of the reagent. Scheme 1The general structure of isoflavones 3 prepared.Downloaded by: University of British Columbia. Copyrighted material.

Oxidation of a methanolic solution of chalcones with hypervalent iodine compounds results in a rearrangement to acetals, if the substrates lack the 2'-hydroxy group [cf. (IV)]. One-pot hydrolysis of the 2-benzoyloxy derivatives (VII) leads to an efficient synthesis of chalcones such as (VIII). Polymer-supported diacetoxyiodostyrene is used under similar conditions. The yields are lower; however, the isoflavones can be easily separated, no Ph-I is liberated and the reagent can be reused. -(KAWAMURA*, Y.; MARUYAMA, M.; TOKUOKA, T.; TSUKAYAMA, M.; Synthesis

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Regioselective Synthesis of 6-Prenylpolyhydroxyisoflavone (Wighteone) and Wighteone Hydrate with Hypervalent Iodine. -The first total synthesis of wighteone (V) and its hydrate (IV) is described. -(HOSSAIN, M. M.; TOKUOKA, T.; YAMASHITA, K.; KAWAMURA, Y.; TSUKAYAMA*, M.; Synth. Commun. 36 (2006) 7-9, 1201-1211; Dep. Chem. Sci. Technol., Fac. Eng., Univ. Tokushima, Minamijosanjima, Tokushima 770, Japan; Eng.) -H. Toeppel 36-196