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Notes and references
1
For recent books and selected reviews on hypervalent iodine chem-
istry, see: (a) Hypervalent Iodine Chemistry: Modern Developments in
Organic Synthesis, ed. T. Wirth, 2003, [Top. Curr. Chem., 2003; 224];
(
b) V. V. Zhdankin, Hypervalent Iodine Chemistry: Preparation, Struc-
ture, and Synthetic Applications of Polyvalent Iodine Compounds,
Wiley, Chichester, 2013; (c) T. Wirth, Angew. Chem., Int. Ed., 2005,
4
4
(
4, 3656; (d) S. Quideau, L. Pouysegu and D. Deffieux, Synlett, 2008,
67; (e) M. Ochiai and K. Miyamoto, Eur. J. Org. Chem., 2008, 4229;
f ) M. Uyanik and K. Ishihara, Chem. Commun., 2009, 2086; (g) T. Dohi
and Y. Kita, Chem. Commun., 2009, 2073; (h) V. V. Zhdankin, ARKIVOC,
009, i, 1; (i) M. S. Yusubov, V. N. Nemykin and V. V. Zhdankin,
Tetrahedron, 2010, 66, 5745; ( j) S. Quideau and T. Wirth, Tetrahedron,
2
Scheme 4 Preparation of a,b-unsaturated carbonyl compounds from alcohols
by oxidation with IBX-tosylate.
2010, 66, 5737; (k) L. F. Silva and B. Olofsson, Nat. Prod. Rep., 2011,
8, 1722; (l) E. A. Merritt and B. Olofsson, Synthesis, 2011, 517;
2
011, i, 370; (n) H. Liang and M. A. Ciufolini, Angew. Chem., Int. Ed.,
of IBX in methanol are stable for several hours. The oxidizing
activity of IBX-OTs 6 toward methanol is similar to 2-iodoxy-
benzenesulfonic acid (IBS), which is one of the most powerful
2
011, 50, 11849; (o) J. P. Brand, D. F. Gonz ´a lez, S. Nicolai and J. Waser,
Chem. Commun., 2011, 47, 102; (p) M. S. Yusubov and V. V. Zhdankin,
Curr. Org. Synth., 2012, 9, 247; (q) D. Fernandez Gonzalez, F. Benfatti
and J. Waser, ChemCatChem, 2012, 4, 955; (r) M. S. Yusubov, D. Yu.
Svitich, M. S. Larkina and V. V. Zhdankin, ARKIVOC, 2013, i, 364;
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0
hypervalent iodine oxidants.
The reaction of alcohols with 3 equiv. of IBX-OTs 6 in DMSO
at room temperature results in an oxidation–dehydrogenation
sequence leading to a,b-unsaturated carbonyl compounds.
Several examples of these reactions are shown in Scheme 4;
additional examples can be found in ESI.† Similar oxidative
dehydrogenation reactions of alcohols or carbonyl compounds
using IBX in DMSO proceed at 65–85 1C and require 24–48 h for
(s) M. Brown, U. Farid and T. Wirth, Synthesis, 2013, 424.
2
G. F. Koser, Aldrichimica Acta, 2001, 34, 89.
3 (a) A. Y. Koposov, B. C. Netzel, M. S. Yusubov, V. N. Nemykin,
A. Y. Nazarenko and V. V. Zhdankin, Eur. J. Org. Chem., 2007, 4475;
(
b) V. N. Nemykin, A. Y. Koposov, B. C. Netzel, M. S. Yusubov and
V. V. Zhdankin, Inorg. Chem., 2009, 48, 4908; (c) M. S. Yusubov,
R. Y. Yusubova, T. V. Funk, K.-W. Chi and V. V. Zhdankin, Synthesis,
2
009, 2505; (d) H. M. Neu, M. S. Yusubov, V. V. Zhdankin and
V. N. Nemykin, Adv. Synth. Catal., 2009, 351, 3168; (e) C. Zhu and
Y. Wei, Catal. Lett., 2011, 141, 582.
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completion, which is indicative of a significantly higher
reactivity of IBX-tosylate compared to IBX.
4 (a) V. V. Zhdankin, C. J. Kuehl, A. P. Krasutsky, J. T. Bolz and
A. J. Simonsen, J. Org. Chem., 1996, 61, 6547; (b) T. Muraki, H. Togo
and M. Yokoyama, J. Org. Chem., 1999, 64, 2883.
(a) T. Wirth, Angew. Chem., Int. Ed., 2001, 40, 2812; (b) U. Ladziata
and V. V. Zhdankin, ARKIVOC, 2006, ix, 26; (c) V. Satam, A. Harad,
R. Rajule and H. Pati, Tetrahedron, 2010, 66, 7659; (d) A. Duschek
and S. F. Kirsch, Angew. Chem., Int. Ed., 2011, 50, 1524;
It should be noted that, in contrast to compound 6, a
mechanical mixture of IBX and TsOH does not demonstrate any
significant increase in oxidizing reactivity as compared to IBX. The
generation and use of reagent 6 in situ is not feasible, because the
reaction of IBX with TsOH requires acetic anhydride as a solvent
and the product immediately precipitates from the solution.
In conclusion, we have reported the preparation of new
powerful hypervalent iodine(V) oxidants, tosylate and mesylate
derivatives of 2-iodoxybenzoic acid (IBX), by the reaction of IBX with
the corresponding sulfonic acids. Single crystal X-ray crystallo-
graphy of the diacetate derivative of IBX-tosylate 5 revealed an
unusual heptacoordinated iodine geometry without any signifi-
cant intermolecular secondary interactions. According to X-ray
data, the I–O(tosyl) bond in compound 5 has a significantly
ionic character, which may lead to a higher electrophilic
reactivity of the sulfonate derivatives of 2-iodoxybenzoic acid.
The pentavalent iodine tosylate 6 can be used as an efficient
oxidizing reagent for a selective oxidation of alcohols to the
respective carbonyl compounds and for a one-pot conversion of
alcohols to a,b-unsaturated carbonyl compounds.
5
(
e) V. V. Zhdankin, J. Org. Chem., 2011, 76, 1185.
6 P. K. Sajith and C. H. Suresh, Inorg. Chem., 2012, 51, 967.
(a) R. K. Boeckman, P. Shao and J. J. Mullins, Org. Synth., 2000,
7, 141; (b) U. Ladziata, A. Y. Koposov, K. Y. Lo, J. Willging,
7
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V. N. Nemykin and V. V. Zhdankin, Angew. Chem., Int. Ed., 2005,
44, 7127; (c) M. S. Yusubov, K.-W. Chi, J. Y. Park, R. Karimov and
V. V. Zhdankin, Tetrahedron Lett., 2006, 47, 6305; (d) A. Y. Koposov,
R. R. Karimov, A. A. Pronin, T. Skrupskaya, M. S. Yusubov and
V. V. Zhdankin, J. Org. Chem., 2006, 71, 9912.
8 A. Schroeckeneder, D. Stichnoth, P. Mayer and D. Trauner, Beilstein
J. Org. Chem., 2012, 8, 1523.
9
(a) T. Dohi, N. Yamaoka and Y. Kita, Tetrahedron, 2010, 66, 5775;
b) A. Yoshimura, K. R. Middleton, M. W. Luedtke, C. Zhu and
(
V. V. Zhdankin, J. Org. Chem., 2012, 77, 11399; (c) A. Yoshimura,
K. R. Middleton, A. D. Todora, B. J. Kastern, S. R. Koski,
A. V. Maskaev and V. V. Zhdankin, Org. Lett., 2013, 15, 4010.
1
0 (a) A. Y. Koposov, D. N. Litvinov, V. V. Zhdankin, M. J. Ferguson,
R. McDonald and R. R. Tykwinski, Eur. J. Org. Chem., 2006, 4791;
(
b) M. Uyanik, M. Akakura and K. Ishihara, J. Am. Chem. Soc., 2009,
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31, 251; (c) M. Uyanik and K. Ishihara, Aldrichimica Acta, 2010,
3, 83.
This work was supported by a research grant from the NSF 11 (a) K. C. Nicolaou, Y. L. Zhong and P. S. Baran, J. Am. Chem. Soc.,
2
000, 122, 7596; (b) K. C. Nicolaou, T. Montagnon, P. S. Baran and
(
CHE-1262479). M.S.Y. and V.V.Z. are also thankful to the Govern-
ment of Russia for support of their cooperative research program
Russian Foundation for Basic Research No. 12-03-00978-a).
Y. L. Zhong, J. Am. Chem. Soc., 2002, 124, 2245; (c) B. Bradshaw,
G. Etxebarria-Jardi and J. Bonjoch, J. Am. Chem. Soc., 2010,
132, 5966.
(
This journal is c The Royal Society of Chemistry 2013
Chem. Commun., 2013, 49, 11269--11271 11271