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.
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.
