O-Iodoxybenzoic acid and
related iodoxyarenes
Edmund William Dwerryhouse Burke
Wednesday 23rd February 2011
History
• Discovered in at the end of the 19th
century
• Biologically tested and used as a medicine
• Not really used until the end of the 20th
Structure and bonding
• O-iodoxybenzoic acid (IBX), exists in a single
tautomeric form, IUPAC name;
1-hydroxy-1-oxo-1H-1l5-benzo[d][1,2]iodoxol-3-one
• Planar except for O4, leading to chirality
• Can be crystallize as a conglomerate
• Octahedral geometry around iodine due to
intermolecular I-O interactions
S. F. Kirsch and A. Duschek, Angew. Chem. Int. Ed. 2011, 50, 1524 – 1552
More bonding
• Hypervalent bonding
– Hypervalent atom may have colinear single bonds
– Two types of single bond from the same atom
– Doubly occupied p-orbitals
– Oxo ligand is associate via a dative bond
J. I. Musher, Angew. Chem. Internat. Edit. Vol. 8 (1969), 54-68
S. F. Kirsch and A. Duschek, Angew. Chem. Int. Ed. 2011, 50, 1524 – 1552
Preparation
• Numerous methods have been reported, either
via oxidation of 2-iodosobenzoic acid or 2iodobenzoic acid. Method of choice is now:
Marco Frigerio, Marco Santagostino, and Simona Sputore, J. Org. Chem. 1999, 64, 4537-4538
Advantages of IBX and its
derivatives
•
•
•
•
Environmentally safe
Stable in presence of water and oxygen
Can be regenerated
Compatible with a wide range of common
protecting groups
• Does not over oxidise aldehydes to acids
• Does not oxidise tertiary amines or
heterocycles
Disadvantages of IBX and its
derivatives
• Lack of solubility in most organic solvents
• Explosive
Overcome by
•Polymer bound IBX
•Use of SIBX, formulation of
benzoic acid, 2-iodobenzoic
acid, and IBX
•Derivatives
Marcel M¸lbaier and Athanassios Giannis, Angew. Chem. Int. Ed. 2001, 40, 4393-4394
Mechanism
Hypervalent twist mechanism
S. F. Kirsch and A. Duschek, Angew. Chem. Int. Ed. 2011, 50, 1524 – 1552
In situ generation of IBX
C. Bulman Page, L. F. Appleby, B. R. Buckley, S. M. Allin, M. J. McKenzieb, Synlett 2007, No. 10, 1565–1568
Some Derivatives
Jarugu Narasimha Moorthy, Nidhi Singhal and Kalyan Senapati, Tetrahedron Lett. 49 (2008) 80–84
S. F. Kirsch and A. Duschek, Angew. Chem. Int. Ed. 2011, 50, 1524 – 1552
Example use of a derivative
2 eq.
DCM, rt. 1h
87 %
Paul A. Grieco,' Jon L. Collins,* Eric D. Moher Thomas J. Fleck, and Raymond S. Gross, J. Am.
Chem. SOC. 1993, 115, 6078-6093
Some examples using
Me-IBX
Jarugu Narasimha Moorthy, Nidhi Singhal and Kalyan Senapati, Tetrahedron Lett. 49 (2008) 80–84
Sulphides to sulphoxides
Jarugu Narasimha Moorthy, Nidhi Singhal and Kalyan Senapati, Tetrahedron Lett. 49 (2008) 80–84
Single electron transfer mechanism
for the oxidation of sulphides
IBX and Diols
• Also make hemiaminals, then lactams
One pot reactions
Fredy Leon, Daniel G. Rivera, and Ludger A. Wessjohann, J. Org. Chem., 73, 2008, 1762-1767
Dehydrogenation with IBX
• Aromatization
• Dehydrogenation of carbonyls
K. C. Nicolaou, T. Montagnon, P. S. Baran, and Y.-L. Zhong, J. Am. Chem. Soc., 124, 2002, 2245-2258
Dearomatization of Phenols
Derek Magdziak, Andy A. Rodriguez, Ryan W. Van De Water, and Thomas R. R. Pettus, Org. Lett., 4, 2002,
285-288
Evidence for the mechanism of Phenol
dearomatization
Summary
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•
•
•
Broad array of reactions
Various reaction mechanisms
Mild and selective oxidising agents
Easy to use