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Chemicals >> Oxidizing Agents > Hypervalent Iodine Compounds

Koser's Reagent
Hydroxy(tosyloxy)iodobenzene (HTIB)

HTIB is a commercially available reagent for the phenyliodination and oxytosylation of a range of organic substrates. For examples, ketones give α-tosyloxyketones, whereas alkenes form 1,2-ditosyloxyalkanes via syn addition.

A recently reported method enables a convenient access to Koser's Reagent and derivatives:

E. A. Merritt, V. M. T. Carneiro, L. F. Silva Jr., B. Olofsson, J. Org. Chem., 2010, 75, 7416-7419.54.

Recent Literature

Various α-tosyloxyketones were efficiently prepared in high yields from the reaction of ketones with m-chloroperbenzoic acid and p-toluenesulfonic acid in the presence of a catalytic amount of iodobenzene.
Y. Yamamoto, H. Togo, Synlett, 2006, 798-800.

Various ketones could be reacted into α-tosyloxy ketones in the presence of MCPBA, PTSA•H2O, catalytic amounts of iodine and tert-butylbenzene in a mixture of acetonitrile and 2,2,2-trifluoroethanol. In the reaction, 4-tert-butyl-1-iodobenzene is formed at first and then converted into the α-tosyloxylation reagent 4-tert-butyl-1-[(hydroxy)(tosyloxy)iodo]benzene by the reaction with MCPBA and PTSA•H2O.
A. Tanaka, K. Moriyama, H. Togo, Synlett, 2011, 1853-1854.

Enol esters were rapidly converted in high yields to their corresponding α-tosyloxy ketones in the presence of [hydroxy(tosyloxy)iodo]benzene (HTIB). Aromatic, aliphatic, and cyclic enol esters were found to be suitable substrates for the reaction.
B. Basdevant, C. Y. Legault, J. Org. Chem., 2015, 80, 6897-6902.

HTIB mediates an oxidative transposition of vinyl halides to provide α-halo ketones as useful and polyvalent synthetic precursors. Insights into the mechanism and an enantioselective transformation are reported too.
A. Jobin-Des Lauriers, C. Y. Legault, Org. Lett., 2016, 18, 108-111.

Dehydrosulfurization using a hypervalent iodine(III) reagent enables a simple and efficient preparation of symmetrical and unsymmetrical carbodiimides from the corresponding thioureas. The oxidation afforded carbodiimides in excellent yields and high selectivity. A possible mechanism for the transformation is proposed.
C. Zhu, D. Xu, Y. Wei, Synthesis, 2011, 711-714.

Poly{[4-(hydroxy)(tosyloxy)iodo]styrene} was efficient in the halotosyloxylation reaction of alkynes with iodine or NBS or NCS. The polymer reagent could be regenerated and reused.
J.-M. Chen, X. Huang, Synthesis, 2004, 1557-1558.