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.
The use of Koser's reagent enables an efficient synthesis of
3-tosyloxy-4-hydroxycoumarins under mild conditions. The reaction tolerates
various functional groups.
B. Xu, Y. Gao, J. Han, Z. Xing, S. Zhao, Z. Zhang, R. Ren, L. Wang, J. Org. Chem., 2019,
84, 10136-10144.