Oxidative functionalization, hypervalent iodine-catalyzed

Singh FV, Wirth T. Hypervalent iodine-catalyzed oxidative functionalizations including stereoselective reactions. Chem Asian J. 2014 9 950-971. 

Similarly, chelation-assisted palladium-catalyzed oxidative functionalizations of C—H bonds with, for example, hypervalent iodine(III) reagents turned out to be particularly valuable. These protocols allowed for, inter alia, regioselective acetoxyla-tion or etherification of aromatic and aliphatic C— H bonds [17-19], and also halogenations of arenes (Scheme 9.3) [20, 21]. 

Tsarevsky has found that hypervalent iodine compounds can be used for the direct azidation of polystyrene and consecutive click-type functionalization [49]. In particular, polystyrene can be directly azidated in 1,2-dichloroethane or chlorobenzene using a combination of trimethylsilyl azide and (diacetoxyiodo)benzene. 2D NMR HMBC spectra indicate that the azido groups are attached to the polymer backbone and also possibly to the aryl pendant groups. Approximately one in every 11 styrene units can be modified by using a ratio of PhI(OAc)2 to trimethylsilyl azide to styrene units of 1 2.1 1 at 0 °C for 4 h followed by heating to 50 °C for 2 h in chlorobenzene. The azidated polymers have been further used as backbone precursors in the synthesis of polymeric brushes with hydrophilic side chains via a copper-catalyzed click reaction with poly(ethylene oxide) monomethyl ether 4-pentynoate [49],... 

Hypervalent iodine(III) mediated/catalyzed intramolecular oxidative C-H bond functionalization of (hetero)arenes and alkenes has been widely applied in the synthesis of several biologically active heterocyclic scaffolds. This intramolecular oxidative C-H bond functionalization reaction leads to the formation of carbon-carbon and carbon-heteroatom bonds in an efficient manner. Of all bond formation reactions, C-N bond annulations have been exploited most and are of immense... 

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