One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

  1. Natalia Soldatova1,
  2. Pavel Postnikov1ORCID Logo,
  3. Olga Kukurina1ORCID Logo,
  4. Viktor V. Zhdankin1,2ORCID Logo,
  5. Akira Yoshimura1ORCID Logo,
  6. Thomas Wirth3ORCID Logo and
  7. Mekhman S. Yusubov1ORCID Logo

1The Tomsk Polytechnic University, 634050 Tomsk, Russia
2Department of Chemistry and Biochemistry, University of Minnesota, Duluth MN 55812, USA
3School of Chemistry, Cardiff University, Park Place, Main Building, Cardiff CF10 3AT, UK

  1. Corresponding author email

This article is part of the Thematic Series "Hypervalent iodine chemistry in organic synthesis".

Associate Editor: D. Y.-K. Chen
Beilstein J. Org. Chem. 2018, 14, 849–855. https://doi.org/10.3762/bjoc.14.70
Received 18 Feb 2018, Accepted 27 Mar 2018, Published 12 Apr 2018

  • Full Research Paper

Abstract

A facile synthesis of diaryliodonium salts utilizing Oxone as versatile and cheap oxidant has been developed. This method shows wide applicability and can be used for the preparation of iodonium salts containing electron-donating or electron-withdrawing groups in good yields. In addition, this procedure can be applied to the preparation of symmetric iodonium salts directly from arenes via a one-pot iodination–oxidation sequence.

Keywords: diaryliodonium salts; iodine; iodonium; oxidation; Oxone

Introduction

Diaryliodonium salts, which are also known as diaryl-λ3-iodanes, are widely considered to be an important and practically useful class of hypervalent iodine compounds [1-4]. Diaryliodonium salts have found broad synthetic application as electrophilic arylating reagents in reactions with various nucleophiles including electron-rich carbon-centered species [5-7]. The unique arylating reactivity of diaryliodonium salts has been demonstrated in many metal-catalyzed and also metal-free transformations [8-15].

The development of novel synthetic approaches to diaryliodonium salts based on the use of inexpensive, commercially available oxidants is an important and challenging goal. A vast majority of existing procedures involve the interaction of electrophilic hypervalent iodine(III) species with suitable arenes through ligand exchange processes [16-20]. The reactive hypervalent iodine(III) species can be used as stable reagents or can be generated in situ [21-25]. In particular, Olofsson and co-workers reported procedures based on the in situ generation of reactive λ3-iodane species directly from arenes, which was a significant achievement in this field [26-29]. However, these now well-established processes involve oxidations using mCPBA in the presence of strong organic acids [30-35]. Therefore, the development of new, convenient and inexpensive methods utilizing readily available and easy-to-handle oxidants still remains a highly desirable goal.

Previously, we have published the utilization of Oxone® (2KHSO5·KHSO4·K2SO4) as a readily available and effective oxidant for the preparation of various hypervalent iodine compounds [36-42]. Oxone is used as an efficient oxidant for the direct conversion of substituted 2-iodobenzoic acids to arylbenziodoxoles [37,38], 2-iodobiphenyl to dibenziodolium compounds [39], iodoarenes to iodylbenzenes and [bis(trifluoroacetoxy)iodo]arenes [40,41], and for the preparation of diaryliodonium trifluoroacetates and triflates [42]. Yakura also used Oxone® as an oxidant for the generation of iodine(III) species in the oxidation of phenols [43]. In the present work, we report the development of a reliable and convenient procedure for the preparation of diaryliodonium bromides using Oxone in the presence of sulfuric acid.

Results and Discussion

After having investigated previously described reaction conditions [37,38], initial optimization studies were performed using iodobenzene and toluene as reactants for the synthesis of diaryliodonium salt 3a (Table 1). A simple mixing of the starting materials with finely ground Oxone and sulfuric acid leads to the formation of a very viscous and dark reaction mixture (Table 1, entry 1). Full conversion of the starting materials could not be achieved even after 24 h stirring. The addition of aqueous KBr to the reaction mixture resulted in the formation of the desired bromide salt 3a in 30% isolated yield. The addition of KBr is necessary as the high solubility of the diaryliodonium sulfonates does not allow their isolation from the reaction mixture. Dilution of the reaction mixture with dichloromethane did not increase the yield of the target product significantly (Table 1, entry 2). Moreover, we observed the formation of 4-iodobenzenesulfonic acid in both cases, probably due to the high concentration of sulfuric acid in the reaction mixture. Mixing dichloromethane with acetonitrile resulted in an increased yield of 3a and a decreased amount of 4-iodobenzenesulfonic acid (Table 1, entry 3). When the reaction was carried out in pure acetonitrile, the iodonium salt 3a was formed in 75% yield (Table 1, entry 4). The addition of 2 equivalents of Oxone increased the yield to 92% (Table 1, entry 5). Surprisingly, a smaller amount of toluene did not affect the yield (Table 1, entry 6). In order to avoid the formation of undesired 4-iodobenzenesulfonic acid, the reaction was carried out using smaller amounts of acid (Table 1, entries 7 and 8). That reaction proceeds smoothly with only 7.5 equivalents of sulfuric acid producing the target compound 3a high yields. However, the use of 3.75 equivalents of sulfuric acid resulted in a significantly lower yield.

Table 1: Optimization studies.a

[Graphic 1]
entry solvent toluene (equiv) Oxone (equiv) H2SO4 (equiv) yieldb (%)
1 – 2.8 1.3 15 30c
2 CH2Cl2 2.8 1.3 15 40c
3 CH2Cl2/MeCN 2.8 1.3 15 60c
4 MeCN 2.8 1.3 15 75c
5 MeCN 2.8 2 15 92c
6 MeCN 1.2 2 15 88c
7 MeCN 1.2 2 7.5 86
8 MeCN 1.2 2 3.75 53

aReaction conditions: PhI (1 mmol), overnight, rt; bisolated yield; caccording to NMR data product contains up to 10% of (4-tolyl)phenyliodonium 4-iodobenzenesulfonate as an impurity.

With the optimized procedure, the synthetic utility of this method using various aryliodides and arenes was investigated (Table 2). Iodobenzene (1a) smoothly reacts with arenes containing electron-donating substituents to form the corresponding iodonium salts in high yields. 3-Trifluoromethyliodobenzene (1b) exhibited higher reactivity, and iodonium salts have been isolated in higher yields. Moreover, iodoarene 1b reacted with the moderately electron-poor chlorobenzene (2e) forming iodonium salt 3i in 51% yield. In contrast, 4-bromoiodobenzene (1c) was less reactive and afforded iodonium salts 3j–m in lower yields. Similar reactions of 3,5-bis(trifluoromethyl)iodobenzene (1d) with benzene and mesitylene formed the corresponding iodonium salts 3n and 3o in moderate yields.

Table 2: Synthesis of diaryliodonium bromides.a

[Graphic 2]
R1 (1) R2 (2) product 3 yieldb (%)
R1 = H (1a) R2 = Me (2a) [Graphic 3]
3a 		86c
R1 = H (1a) R2 = H (2b) [Graphic 4]
3b 		74d,e,f
R1 = H (1a) R2 = 1,4-Me2 (2c) [Graphic 5]
3c 		75
R1 = H (1a) R2 = 1,3,5-Me3 (2d) [Graphic 6]
3d 		75
R1 = 3-CF3 (1b) R2 = H (2b) [Graphic 7]
3e 		85e,f
R1 = 3-CF3 (1b) R2 = Me (2a) [Graphic 8]
3f 		76c
R1 = 3-CF3 (1b) R2 = 1,4-Me2 (2c) [Graphic 9]
3g 		95
R1 = 3-CF3 (1b) R2 = 1,3,5-Me3 (2d) [Graphic 10]
3h 		92
R1 = 3-CF3 (1b) R2 = Cl (2e) [Graphic 11]
3i 		51g,h
R1 = 4-Br (1c) R2 = Me (2a) [Graphic 12]
3j 		70c
R1 = 4-Br (1c) R2 = 1,4-Me2 (2c) [Graphic 13]
3k 		32
R1 = 4-Br (1c) R2 = 1,3,5-Me3 (2d) [Graphic 14]
3l 		71
R1 = 4-Br (1c) R2 = Cl (2e) [Graphic 15]
3m 		34g,h
R1 = 3,5-(CF3)2 (1d) R2 = H (2b) [Graphic 16]
3n 		35e,f
R1 = 3,5-(CF3)2 (1d) R2 = 1,3,5-Me3 (2d) [Graphic 17]
3o 		62

aReaction conditions: 1 (1 mmol), 2 (1.1 mmol), H2SO4 (7.5 mmol), MeCN (2 mL) overnight, rt; bisolated yield; c1.2 mmol of 2a was used; daccording to NMR data product contains an up to 1.5% of diphenyliodonium 4-iodobenzenesulfonate as impurity; e11.3 mmol of H2SO4 was used; f1.3 mmol of 2b was used; g15 mmol of H2SO4 was used; h1.5 mmol of 2e was used.

With electron-deficient arenes 2 such as chlorobenzene (2e) and benzene, an excess of sulfuric acid and arene was used to improve the yields. Subsequently it was shown that the addition of aqueous potassium bromide can be modified and other counter anions can be introduced to prepare different diaryliodonium salts. This has been demonstrated in the preparation of diaryliodonium salts using 1-iodo-3-trifluoromethylbenzene (1b) and mesitylene (2d) as model substrates (Table 3).

Table 3: Preparation of diaryliodonium salts with different anions.a

[Graphic 18]
NaX / HX product yieldb (%)
NaBr 3h 92
TsOH 3p 82
TfOH 3q 89
NaBF4 3r 81
NaPF6 3s 80

aReaction conditions: 1b (1 mmol), 2d (1.1 mmol), Oxone (1 mmol), H2SO4 (7.5 mmol), MeCN (2 mL), NaX or HX (2 mmol) overnight, rt; bisolated yield.

The yield of the salts 3h and 3p–s do not depend on the nature of the anion and its source. Small differences in yield can be explained by different solubility of salts in acetonitrile/water. Diaryliodonium bromides were isolated in higher yields because of the low solubility of these products (Table 3).

Finally, a one-step procedure for the preparation of symmetric iodonium salts directly from arenes via an in situ iodination was developed (Table 4). Arenes 2b–e can be transformed to the symmetric iodonium salts 3b and 3t–v by the reaction with iodine, Oxone, and sulfuric acid. The attempted synthesis of the symmetric iodonium salt using toluene as substrate led to a regioisomeric mixture of products due to the low regioselectivity of iodination.

Table 4: Preparation of symmetric iodonium salts via a one-step iodination–oxidation procedure.a

[Graphic 19]
R2 (2) product 3 yieldb (%)
R2 = H (2b) [Graphic 20]
3b 		84c,d
R2 = 1,4-Me2 (2c) [Graphic 21]
3t 		80
R2 = 1,3,5-Me3 (2d) [Graphic 22]
3u 		77
R2 = Cl (2e) [Graphic 23]
3v 		40e

aReaction conditions: ArH (2.2 mmol), Oxone (2 mmol), H2SO4 (7.5 mmol), MeCN (2 mL) overnight, rt; bisolated yield; caccording to NMR data the product contains up to 1.5% of diphenyliodonium 4-iodobenzenesulfonate as impurity; d11.3 mmol of H2SO4 and 2.6 mmol of 2b were used; e15 mmol of H2SO4 and 3.0 mmol of 2e were used.

This procedure allowed the synthesis of iodonium salts with arenes containing electron-donating groups. Unfortunately, electron-poor arenes exhibited a lower reactivity and bis-(4-chlorophenyl)iodonium bromide have been isolated in only 40% yield. Nevertheless, the developed procedure is characterized by important advantages, such as simplicity, the use of inexpensive and available reagents, and typically good yields of iodonium salts. It is a versatile addition to the methodology toolbox for the preparation of diaryliodonium salts.

Conclusion

In conclusion, a new facile protocol for the preparation of diaryliodonium salts using cheap and readily available Oxone as an oxidant in the presence of sulfuric acid has been developed. The procedure allows the synthesis of a wide range of iodonium salts containing electron-donating and electron-withdrawing substituents. Particularly attractive is the possibility of the one-pot synthesis of symmetric bis-aryliodonium salts directly from arenes via an iodination–oxidation sequence.

Supporting Information

Supporting Information File 1: Experimental details and NMR spectra.
Format: PDF Size: 4.8 MB Download

Acknowledgements

This work was supported by the Russian Foundation for Basic Research (RFBR-mol_nr 17-33-50111), the Tomsk Polytechnic University Competitiveness Enhancement Program and the Royal Society (IE160304). We thank the EPSRC National Mass Spectrometry Facility, Swansea, for mass spectrometric data.

References

  1. Yusubov, M. S.; Maskaev, A. V.; Zhdankin, V. V. ARKIVOC 2011, i, 370–409. doi:10.3998/ark.5550190.0012.107
    Return to citation in text: [1]
  2. Zhdankin, V. V. Hypervalent Iodine Chemistry; Wiley: Chichester, 2014.
    Return to citation in text: [1]
  3. Yoshimura, A.; Zhdankin, V. V. Chem. Rev. 2016, 116, 3328–3435. doi:10.1021/acs.chemrev.5b00547
    Return to citation in text: [1]
  4. Wirth, T., Ed. Hypervalent Iodine Chemistry in Topics in Current Chemistry; Springer: Berlin, 2016; Vol. 373.
    Return to citation in text: [1]
  5. Merritt, E. A.; Olofsson, B. Angew. Chem., Int. Ed. 2009, 48, 9052–9070. doi:10.1002/anie.200904689
    Return to citation in text: [1]
  6. Aradi, K.; Tóth, B. L.; Tolnai, G. L.; Novák, Z. Synlett 2016, 27, 1456–1485. doi:10.1055/s-0035-1561369
    Return to citation in text: [1]
  7. Fañanás-Mastral, M. Synthesis 2017, 49, 1905–1930. doi:10.1055/s-0036-1589483
    Return to citation in text: [1]
  8. Gonda, Z.; Novák, Z. Chem. – Eur. J. 2015, 21, 16801–16806. doi:10.1002/chem.201502995
    Return to citation in text: [1]
  9. Dey, C.; Lindstedt, E.; Olofsson, B. Org. Lett. 2015, 17, 4554–4557. doi:10.1021/acs.orglett.5b02270
    Return to citation in text: [1]
  10. Tinnis, F.; Stridfeldt, E.; Lundberg, H.; Adolfsson, H.; Olofsson, B. Org. Lett. 2015, 17, 2688–2691. doi:10.1021/acs.orglett.5b01079
    Return to citation in text: [1]
  11. Cahard, E.; Male, H. P. J.; Tissot, M.; Gaunt, M. J. J. Am. Chem. Soc. 2015, 137, 7986–7989. doi:10.1021/jacs.5b03937
    Return to citation in text: [1]
  12. Modha, S. G.; Greaney, M. F. J. Am. Chem. Soc. 2015, 137, 1416–1419. doi:10.1021/ja5124754
    Return to citation in text: [1]
  13. Beaud, R.; Phipps, R. J.; Gaunt, M. J. J. Am. Chem. Soc. 2016, 138, 13183–13186. doi:10.1021/jacs.6b09334
    Return to citation in text: [1]
  14. Yin, K.; Zhang, R. Org. Lett. 2017, 19, 1530–1533. doi:10.1021/acs.orglett.7b00310
    Return to citation in text: [1]
  15. Seidl, T. L.; Stuart, D. R. J. Org. Chem. 2017, 82, 11765–11771. doi:10.1021/acs.joc.7b01599
    Return to citation in text: [1]
  16. Margida, A. J.; Koser, G. F. J. Org. Chem. 1984, 49, 3643–3646. doi:10.1021/jo00193a039
    Return to citation in text: [1]
  17. Kitamura, T.; Matsuyuki, J.-i.; Nagata, K.; Furuki, R.; Taniguchi, H. Synthesis 1992, 945–946. doi:10.1055/s-1992-26272
    Return to citation in text: [1]
  18. Kitamura, T.; Matsuyuki, J.-i.; Taniguchi, H. Synthesis 1994, 147–148. doi:10.1055/s-1994-25423
    Return to citation in text: [1]
  19. Pike, V. W.; Butt, F.; Shah, A.; Widdowson, D. A. J. Chem. Soc., Perkin Trans. 1 1999, 245–248. doi:10.1039/a809349k
    Return to citation in text: [1]
  20. Carroll, M. A.; Pike, V. W.; Widdowson, D. A. Tetrahedron Lett. 2000, 41, 5393–5396. doi:10.1016/S0040-4039(00)00861-3
    Return to citation in text: [1]
  21. Kaźmierczak, P.; Skulski, L. Synthesis 1995, 1027–1032. doi:10.1055/s-1995-4045
    Return to citation in text: [1]
  22. Kryska, A.; Skulski, L. Molecules 2001, 6, 875–880. doi:10.3390/61100875
    Return to citation in text: [1]
  23. Hossain, M. D.; Kitamura, T. Tetrahedron 2006, 62, 6955–6960. doi:10.1016/j.tet.2006.04.073
    Return to citation in text: [1]
  24. Hossain, M. D.; Ikegami, Y.; Kitamura, T. J. Org. Chem. 2006, 71, 9903–9905. doi:10.1021/jo061889q
    Return to citation in text: [1]
  25. Dohi, T.; Yamaoka, N.; Itani, I.; Kita, Y. Aust. J. Chem. 2011, 64, 529–535. doi:10.1071/CH11057
    Return to citation in text: [1]
  26. Bielawski, M.; Zhu, M.; Olofsson, B. Adv. Synth. Catal. 2007, 349, 2610–2618. doi:10.1002/adsc.200700373
    Return to citation in text: [1]
  27. Bielawski, M.; Olofsson, B. Chem. Commun. 2007, 2521–2523. doi:10.1039/b701864a
    Return to citation in text: [1]
  28. Bielawski, M.; Aili, D.; Olofsson, B. J. Org. Chem. 2008, 73, 4602–4607. doi:10.1021/jo8004974
    Return to citation in text: [1]
  29. Zhu, M.; Jalalian, N.; Olofsson, B. Synlett 2008, 592–596. doi:10.1055/s-2008-1032050
    Return to citation in text: [1]
  30. Jalalian, N.; Olofsson, B. Tetrahedron 2010, 66, 5793–5800. doi:10.1016/j.tet.2010.05.004
    Return to citation in text: [1]
  31. Seidl, T. L.; Sundalam, S. K.; McCullough, B.; Stuart, D. R. J. Org. Chem. 2016, 81, 1998–2009. doi:10.1021/acs.joc.5b02833
    Return to citation in text: [1]
  32. Lindstedt, E.; Reitti, M.; Olofsson, B. J. Org. Chem. 2017, 82, 11909–11914. doi:10.1021/acs.joc.7b01652
    Return to citation in text: [1]
  33. Carreras, V.; Sandtorv, A. H.; Stuart, D. R. J. Org. Chem. 2017, 82, 1279–1284. doi:10.1021/acs.joc.6b02811
    Return to citation in text: [1]
  34. Gemoets, H. P. L.; Laudadio, G.; Verstraete, K.; Hessel, V.; Noël, T. Angew. Chem., Int. Ed. 2017, 56, 7161–7165. doi:10.1002/anie.201703369
    Return to citation in text: [1]
  35. Laudadio, G.; Gemoets, H. P. L.; Hessel, V.; Noël, T. J. Org. Chem. 2017, 82, 11735–11741. doi:10.1021/acs.joc.7b01346
    Return to citation in text: [1]
  36. Frigerio, M.; Santagostino, M.; Sputore, S. J. Org. Chem. 1999, 64, 4537–4538. doi:10.1021/jo9824596
    Return to citation in text: [1]
  37. Yusubov, M. S.; Yusubova, R. Y.; Nemykin, V. N.; Zhdankin, V. V. J. Org. Chem. 2013, 78, 3767–3773. doi:10.1021/jo400212u
    Return to citation in text: [1] [2] [3]
  38. Yusubov, M. S.; Soldatova, N. S.; Postnikov, P. S.; Valiev, R. R.; Svitich, D. Y.; Yusubova, R. Y.; Yoshimura, A.; Wirth, T.; Zhdankin, V. V. Eur. J. Org. Chem. 2018, 640–647. doi:10.1002/ejoc.201701595
    Return to citation in text: [1] [2] [3]
  39. Postnikov, P. S.; Guselnikova, O. A.; Yusubov, M. S.; Yoshimura, A.; Nemykin, V. N.; Zhdankin, V. V. J. Org. Chem. 2015, 80, 5783–5788. doi:10.1021/acs.joc.5b00741
    Return to citation in text: [1] [2]
  40. Zagulyaeva, A. A.; Yusubov, M. S.; Zhdankin, V. V. J. Org. Chem. 2010, 75, 2119–2122. doi:10.1021/jo902733f
    Return to citation in text: [1] [2]
  41. Soldatova, N.; Postnikov, P.; Troyan, A. A.; Yoshimura, A.; Yusubov, M. S.; Zhdankin, V. V. Tetrahedron Lett. 2016, 57, 4254–4256. doi:10.1016/j.tetlet.2016.08.038
    Return to citation in text: [1] [2]
  42. Soldatova, N. S.; Postnikov, P. S.; Kukurina, O. S.; Zhdankin, V. V.; Yoshimura, A.; Wirth, T.; Yusubov, M. S. ChemistryOpen 2017, 6, 18–20. doi:10.1002/open.201600129
    Return to citation in text: [1] [2]
  43. Yakura, T.; Omoto, M.; Yamauchi, Y.; Tian, Y.; Ozono, A. Tetrahedron 2010, 66, 5833–5840. doi:10.1016/j.tet.2010.04.124
    Return to citation in text: [1]

Article is part of the thematic issue

Hypervalent iodine chemistry in organic synthesis

Prof. Thomas Wirth

Interesting articles

Synthesis and reactivity of azole-based iodazinium salts

Thomas J. Kuczmera, Annalena Dietz, Andreas Boelke and Boris J. Nachtsheim

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

Xiang Li, Pinhong Chen and Guosheng Liu

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

Fateh V. Singh, Priyanka B. Kole, Saeesh R. Mangaonkar and Samata E. Shetgaonkar

News

Beilstein Glyco-Bioinformatics Symposium 2023 - June 20 to 22, 2023, Limburg, Germany
Logo OA

Take a look at the research you were most interested in last year
Logo OA

ROR allows to connect researchers and their outputs to affiliations
Logo OA

© 2018 Soldatova et al.; licensee Beilstein-Institut.
This is an Open Access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The license is subject to the Beilstein Journal of Organic Chemistry terms and conditions: (https://www.beilstein-journals.org/bjoc)

 
Back to Article List

Other Beilstein-Institut Open Science Activities

Logo
Logo
Logo
Logo

Keep Informed

RSS Feed

Subscribe to our Latest Articles RSS Feed.

Subscribe

Follow the Beilstein-Institut

LinkedIn

Twitter: @BeilsteinInst