Poly[4-hydroxy(tosyloxy)iodo]styrene (high M.W.) and poly{a-methyl[4-hydroxy(tosyloxy)iodo]styrene} (low M.W.) were prepared from polystyrene (average M.W. = 45,000) and poly(a-methylstyrene) (average M.W. = 6,200), respectively, and their reactivities for the a-tosyloxylation of ketones and oxidative atosyloxylation of alcohols were compared with those of [hydroxy(tosyloxy)iodo]benzene.Today, extensive study on hypervalent iodine compounds has been carried out and their potential utility in organic synthesis has been widely recognized. 1 Especially, (diacetoxyiodo)benzene has been popularly used for oxidation in organic synthesis. Based on the extensive utility of (diacetoxyiodo)benzene, we have recently reported the first synthetic use of poly[4-(diacetoxy)iodo]styrene for the iodination of aromatics, oxidative 1,2-aryl migration of alkyl aryl ketones, and oxidation of hydroquinones and sulfides. 2 Here, regeneration and reuse of poly[4-(diacetoxy)iodo]styrene from the recovered poly(4-iodostyrene) were also studied, and its recyclic use has established it as an environmentally benign reagent. After this first report, the synthetic use of poly[4-(diacetoxy)iodo]styrene has become popular. 3 [Hydroxy(tosyloxy)iodo]benzene is another useful hypervalent iodine reagent, especially for the a-tosyloxylation of ketones and esters, the vic-ditosyloxylation of alkenes and the formation of 1-alkynyl-and 1-alkenyliodonium salts. 4 Thus, [hydroxy(tosyloxy)iodo]benzene is one of the most useful reagents for organic synthesis, similarly to (diacetoxyiodo)benzene. Here, two types of new polymer reagents, poly[4-hydroxy(tosyloxy)iodo]styrene (high M.W.) and poly{a-methyl[4-hydroxy(tosyloxy)iodo]styrene} (low M.W.) were prepared from polystyrene (average M.W. = 45,000) and poly(amethylstyrene) (average M.W. = 6,200), respectively. 5 In the preparation of poly[4-hydroxy(tosyloxy)iodo]styrene and poly{a-methyl[4-hydroxy(tosyloxy)iodo]styrene}, NMR measurement of the formed acetic acid in the exchange reaction of the acetoxy groups in poly[4-(diacetoxy)iodo]styrene and poly{a-methyl[(diacetoxy)iodo]styrene} with p-toluenesulfonic acid monohydrate, suggests that the conversion of [4-(diacetoxy)iodo]phenyl groups to 4-[hydroxy(tosyloxy)iodo]phenyl groups proceeds quantitatively, and elemental analysis suggest up to 80% of the phenyl groups in polystyrene and poly(a-methylstyrene) bear the hydroxy(tosyloxy)iodo groups. The a-tosyloxylation of ketones with poly[4-hydroxy(tosyloxy)iodo]styrene and poly{a-methyl[4-hydroxy(tosyloxy)iodo]styrene} was carried out, and the reactivities were compared with that of [hydroxy(tosyloxy)iodo]benzene, based on the literature method. 4 The results are shown in Table 1. 6 The results suggest that poly[4-hydroxy(tosyloxy)iodo]styrene and poly{a-methyl[4-hydroxy(tosyloxy)iodo]styrene} show the same reactivity as [hydroxy(tosyloxy)iodo]benzene. However, there is no big difference in the reactivity between poly[4-hydroxy(tosyloxy)iodo]styrene and poly{a-methyl[4-hydroxy(tosyloxy)iodo]styrene}, despite th...
