IBX Oxidation

IBX Oxidation

Overall Score4
  • Generality
  • Reagent Availability
  • Experimental User Friendliness
  • General Characteristics

2-Iodoxybenzoic acid (IBX) is a mild and versatile oxidant. It can be easily prepared from 2-iodobenzoic acid and Oxone (See the Dess-Martin oxidation as reference).

IBX had long been rarely used as a reagent because of its poor solubility in organic solvents other than DMSO. New interesting reactions are being explored recently by Nicolaou and others.

  • General References

・Frigero, M.; Santagostino, M. Tetrahedron Lett. 1994, 35, 8019. DOI:10.1016/0040-4039(94)80038-3
・De Munari, S.; Frigero, M.; Santagostino, M. J. Org. Chem. 1996, 61, 9272. DOI: 10.1021/jo961044m
・Moore, J. D.; Finney, S. N. Org. Lett. 2002, 4, 3001. DOI: 10.1021/ol026427n
・Nicolaou, K. C.; Zhong, Y. L.; Baran, P. S. J. Am. Chem. Soc. 2000122, 7596. DOI: 10.1021/ja001825b
・Nicolaou, K. C.; Montagnon, T.; Baran, P. S.; Zhong, Y.-L. J. Am. Chem. Soc. 2002124, 2245. DOI:10.1021/ja012127+
・Nicolaou, K. C.; Mathison, C. J. N.; Montagnon, T. Angew. Chem. Int. Ed. 2003, 42, 4077. DOI:10.1002/anie.200352076 

  • Reaction Mechanism

The addition of water is known to decrease the reactivity, which is rationalized by the reversible ligand exchange mechanism. (ref: J. Am. Chem. Soc. 2005, 127, 14146.)

IBX_2[1]

  • Examples

Whereas the Dess-Martin reagent cleaves 1,2-diols, IBX can oxidize them without breaking them up.[1]

IBX_3[1]

IBX is also useful to prepare α,β-unsaturated ketones.[2]

IBX_5[1]

It can also oxidize benzylic methyl groups into aldehydes.[3]

IBX_4[1]

The oxidation of amines to imines is also possible with IBX.[4]

IBX_6[1]

The oxidation to carboxylic acids is possible by adding N-hydroxysuccinimide. The functional group selectivity is high.[5a] Using Oxone as a reoxidant under heating conditions, IBX can be substoichiometric.[5b]

IBX_7[1]

IBX_8[1]

Selective oxidation of secondary hydroxyl groups in the presence of primary hydroxyl groups is possible.[6]

IBX_9[1]

2-Iodobenzenesulfonic acid acts as a highly active oxidation catalyst. It forms a sulfonic acid analogue of IBX in situ.[7]

IBX_10[1]

The conversion of amides into nitriles with one-carbon dehomologation.[8]

IBX_11[1]

  • Experimental Procedure

  • Experimental Tips

IBX has well-known for its hazard risks as a potential explosive.[9] Special caution is required when carrying out the reaction on a large scale.

  • References

[1]
[2]
[3]
[4]
[5] (a) Mazitschek, R.; Mulbaier, M. M.; Giannis, A. Angew. Chem. Int. Ed. 2002, 41, 4059. [abstract] (b) Thottumkara, A. P.; Bowsher, M. S.; Vinod, T. K. Org. Lett. 2005, 7, 2933. DOI: 10.1021/ol050875o
[6] Kuhakarn, C.; Kittigowittana, K.; Pohmakotr, M.; Reutrakul, V. Tetrahedron 2005, 61, 8995. DOI: 10.1016/j.tet.2005.07.051
[7] Uyanik, M.; Akakura, M.; Ishihara, K. J. Am. Chem. Soc. 2009, 131, 251. DOI: 10.1021/ja807110n
[8] Bhalarao, D. S; Mahajan, U. S.; Chaudhari, K. H.; Akamanchi, K. G. J. Org. Chem. 2007, 72, 662. DOI: 10.1021/jo0619074
[9] Plumb, J. B.; Harper, D. J. C&EN News 1990, July 16, 3.

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