Iodosylbenzene oligomeric

Oligomeric iodosylbenzenes 26 and 27 have been prepared by ligand exchange in X. -iodanes under moderately acidic conditions. The oligomer 26 was obtained by the treatment of PhI(OAc)2 with aqueous NaHS04 [116,117], while product 27 precipitated from dilute aqueous solutions of PhI(OH)OTs and Mg(C104)2 [118] (Scheme 2.13). The formation of both products can be explained by self-assembly of the hydroxy(phenyl)iodonium ions (Phl+OH in hydrated form) and [oxo(aquo)iodo]benzene PhI+(0H2)0 in aqueous solution under the reaction conditions. 

Under similar conditions, but in the absence of external nucleophiles, cyclohexene with Phl+OBFs affords formylcyclopentane (169) (Scheme 3.71) [219]. The rearranged product 169 is also formed in the reaction of cyclohexene with oligomeric iodosylbenzene sulfate, (PhI0)3S03 [163], or with (PhIO) in aqueous H2SO4 [220]. 

The oligomeric iodosylbenzene sulfate 20 is a readily available, stable and water-soluble reagent with a reactivity pattern similar to that of activated iodosylbenzene [35-40]. It reacts with alkenes, alcohols and aryl alkyl sulfides in aqueous acetonitrile at room temperature to afford the respective products of oxidation 21-24 in good yields (Scheme 6.11) [35,36],... 

Zhu and Wei have reported a mild and highly efficient procedure for the oxidation of alcohols to the corresponding aldehydes or ketones using oligomeric iodosylbenzene sulfate 20 in water in the presence of 3-cyclodextrin, which serves as a biomimetic catalyst. The oxidation proceeded in water to afford aldehydes or ketones in excellent yields and high selectivity without overoxidation to carboxylic acids [41],... 

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