2-Iodoxybenzoic acid

correct correct 477213687 IBXAcid.png skin-invert 2-iodoxybenzoic-acid-from-xtal-1997-3D-balls.png bg-transparent 2-iodoxybenzoic-acid-from-xtal-1997-3D-sf.png bg-transparent 1-Hydroxy-1λ5,2-benziodoxole-1,3-dione 1-Hydroxy-1λ3,2-benziodoxol-3(1H)-one 1-oxide correct ?? 61717-82-6 976364 correct EBI 118857 correct EBI 52701 correct chemspider 300947 339496 3K0C43POH0 1/C7H5IO4/c9-7-5-3-1-2-4-6(5)8(10,11)12-7/h1-4H,(H,10,11) CQMJEZQEVXQEJB-UHFFFAOYAL correct chemspider 1S/C7H5IO4/c9-7-5-3-1-2-4-6(5)8(10,11)12-7/h1-4H,(H,10,11) correct chemspider CQMJEZQEVXQEJB-UHFFFAOYSA-N O=C1OI(=O)(O)c2ccccc12 c1ccc2c(c1)C(=O)OI2(=O)O 7 5 1 4 233 °C (decomposes) 05 07 Danger 314 315 319 335 260 261 264 271 280 301+330+331 302+352 303+361+353 304+340 305+351+338 310 312 321 332+313 337+313 362 363 403+233 405 501 2-Iodoxybenzoic acid (IBX) is an organic compound used in organic synthesis as an oxidizing agent. This periodinane is especially suited to oxidize alcohols to aldehydes. IBX is most often prepared from 2-iodobenzoic acid and a strong oxidant such as potassium bromate and sulfuric acid, Dess–Martin periodinane: 1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one Boeckman, R. K. Jr. Shao, P. Mullins, J. J. 2000 77 141 10 696 v77p0141 or more commonly, oxone. One of the main drawbacks of IBX is its limited solubility; IBX is insoluble in many common organic solvents. IBX is an impact- and heat-sensitive explosive (>200°C). A User-Friendly Entry to 2-Iodoxybenzoic Acid (IBX) Frigerio, M. Santagostino, M. Sputore, S. Journal of Organic Chemistry 1999 64 12 4537–4538 10.1021/jo9824596 Commercial IBX is stabilized by carboxylic acids such as benzoic acid and isophthalic acid. Preparation IBX can be prepared in a single step by adding an excess of oxone to an aqueous solution of 2-iodobenzoic acid. After warming the solution to 70°C for three hours, the precipitated IBX is collected as a white crystalline solid (80% yield, ≥95% purity). Decomposition of IBX to 2-iodosobenzoic acid and 2-iodobenzoic acid occurs at elevated temperatures, and therefore purification by recrystallization from water is not possible. Purity can be increased (≥99%) by shorting the reaction time to one hour at 70°C, at the cost of slightly reducing yield to 77%. A User-Friendly Entry to 2-Iodoxybenzoic Acid (IBX) Frigerio, M. Santagostino, M. Sputore, S. Journal of Organic Chemistry 1999 64 12 4537–4538 10.1021/jo9824596 center|thumb|IBX Preparation from 2-iodobenzoic acid and Oxone. Reaction mechanism The reaction mechanism for an oxidation of an alcohol to an aldehyde according to the hypervalent twisting mechanism Enhancing 2-Iodoxybenzoic Acid Reactivity by Exploiting a Hypervalent Twist Su, J. T. Goddard, W. A. III Journal of the American Chemical Society 2005 127 41 14146–14147 10.1021/ja054446x 16218584 2005JAChS.12714146S https://authors.library.caltech.edu/76780/2/ja054446xsi20050824_011746.pdf involves a ligand exchange reaction replacing the hydroxyl group by the alcohol followed by a twist and an elimination reaction. The twist is a requirement because the iodine to oxygen double bond is oriented out of plane with the alkoxy group and the concerted elimination would not be able to take place. This twist reaction is a rearrangement in which the oxygen atom is moved into a proper plane for a 5 membered cyclic transition state in the elimination reaction and is calculated by Computational chemistry to be the rate-determining step in the oxidation. The twist mechanism also explains why oxidation is faster for larger alcohols than for small alcohols. The twist is driven forward by the steric hindrance that exists between the ortho hydrogen atom and the protons from the alkoxy group and larger alkoxy groups create larger steric repulsion. The same computation predicts a much faster reacting IBX derivative with a 100 fold reaction rate when this ortho hydrogen atom is replaced by a methyl group thus facilitating the twist until the elimination reaction takes prevalence as the rate determining step. center|frame|alt=Hypervalent twisting mechanism|The hypervalent twisting mechanism during conversion of methanol to formaldehyde: a) ligand exchange reaction (activation energy 9.1 kcal/mol (38 kJ/mol), b) hypervalent twist 12.1 kcal/mol (51 kJ/mol), c) elimination 4.7 kcal/mol (20 kJ/mol)). IBX exists as two tautomers, one of which is the carboxylic acid. The acidity of IBX which has been determined in water (pKa 2.4) and DMSO (pKa 6.65) o-Iodoxybenzoic Acid (IBX): pKa and Proton-Affinity Analysis Gallen, M. J. Goumont, R. Clark, T. Terrier, F. Williams, C. M. Angewandte Chemie International Edition 2006 45 18 2929–2934 10.1002/anie.200504156 16566050 free is known to affect organic reactions, for instance acid-catalyzed isomerization accompanying oxidations. Scope IBX is also available as silica gel or polystyrene bound IBX. In many applications, IBX is replaced by Dess–Martin periodinane which is more soluble in common organic solvents. A sample reaction is an IBX oxidation used in the total synthesis of eicosanoid: Mohapatra, D. K. Yellol, G. S. Asymmetric Total Synthesis of Eicosanoid Arkivoc 2005 2005 3 144–155 10.3998/ark.5550190.0006.316 free 2027/spo.5550190.0006.316 free More and FinneyMore J.D. Finney N.S. A Simple and Advantageous Protocol for the Oxidation of Alcohols with o-Iodoxybenzoic Acid (IBX) Organic Letters 2002 4 17 3001–3003 10.1021/ol026427n 12182609 and Van ArmanVan Arman S 2-Methyl-2-propanol as solvent for o-iodoxybenzoic acid (IBX) oxidation of 1˚ alcohols to aldehydes Tetrahedron Letters 2009 50 33 4693–4695 10.1016/j.tetlet.2009.06.045 have demonstrated that common organic solvents are suitable for many IBX oxidations, despite its low solubility, and in fact may simplify product purification. center|frame|IBX oxidation of alcohol to aldehyde, 94% chemical yield (Mohapatra, 2005) In 2001, K. C. Nicolaou and co-workers published a series of papers in the Journal of the American Chemical Society demonstrating, among other transformations, the use of IBX to oxidize primary and secondary benzylic carbons to aromatic aldehydes and ketones, respectively.Nicolaou K. C. Montagnon T. Baran P. S. Zhong Y.-L. 2002-03-01 Iodine(V) Reagents in Organic Synthesis. Part 4. o-Iodoxybenzoic Acid as a Chemospecific Tool for Single Electron Transfer-Based Oxidation Processes Journal of the American Chemical Society 124 10 2245–2258 10.1021/ja012127+ 11878978 2002JAChS.124.2245N 0002-7863 The presence of additional water in the solution is now considered to be an essential part of those oxidations.Blog Syn Secret Ingredient See Arr Oh 2013-03-03 https://blog-syn.blogspot.com/2013/03/blog-syn-003a-secret-ingredient.html Oxidative cleavage IBX is notable for oxidizing vicinal diols (or glycols) to diketones without cleavage of the carbon-carbon bond,Frigerio, M. Santagostino, M. A Mild Oxidizing Reagent for Alcohols and 1,2-Diols: o-Iodoxybenzoic Acid (IBX) in DMSO Tetrahedron Letters 1994 35 43 8019–8022 10.1016/0040-4039(94)80038-3 but oxidative cleavage of glycols to two aldehydes or ketones can occur when modified conditions are used (elevated temperatures or trifluoroacetic acid solvent).Moorthy, J. N. Singhal, N. Senapati, K. Oxidative Cleavage of Vicinal Diols: IBX can do what Dess–Martin Periodinane (DMP) can Organic & Biomolecular Chemistry 2007 5 5 767–771 10.1039/b618135j 17315062 400px|Oxidative cleavage of vicinal diols The reaction mechanism for this glycol cleavage is based on initial formation of an adduct between 10-I-4 IBX and DMSO to a 12-I-5 intermediate 3 in which DMSO acts as a leaving group for incoming alcohol 4 to intermediate 5. One equivalent of water is split off forming 12-I-5 spirobicyclic periodinane 6 setting the stage for fragmentation to 7. With hydroxyl alpha protons present, oxidation to the acyloin competes. Trifluoroacetic acid is found to facilitate the overall reaction. 400px|Oxidative cleavage of vicinal diols: mechanism α-Hydroxylations Kirsch and co-workers were able to hydroxylate keto compounds with IBX in α-position under mild conditions. Kirsch, S. F. IBX-Mediated α-Hydroxylation of α-Alkynyl Carbonyl Systems. A Convenient Method for the Synthesis of Tertiary Alcohols Journal of Organic Chemistry 2005 70 24 10210–10212 10.1021/jo051898j 16292876 This method could be extended to β-keto esters,Kirsch, S. F. Duschek, A. Novel Oxygenations with IBX Chemistry: A European Journal 2009 15 41 10713–10717 10.1002/chem.200901867 19760735 and forms a regioselective way to introduce conjugatively activated unsaturation.https://www.organic-chemistry.org/Highlights/2011/04April.shtm 4 April 2011 Douglass Taber The Ma Synthesis of (-)-GB 13 Discussion of intermediate 2 Organic Chemistry Highlights Oxidation of β-hydroxyketones to β-diketones Bartlett and Beaudry discovered that IBX is a valuable reagent for the transformation of β-hydroxyketones to β-diketones. IBX provides yields superior to both the Swern and Dess–Martin oxidation protocols.Bartlett, S.L. Beaudry, C.M. High Yielding Oxidation of β-Hydroxyketones to β-Diketones Using o-Iodoxybenzoic Acid Journal of Organic Chemistry 2011 76 23 9852–9855 10.1021/jo201810c 22023037 References Category:Iodates Category:Periodinanes Category:Iodine heterocycles Category:Oxygen heterocycles Category:Reagents for organic chemistry Category:Oxidizing acids Category:Heterocyclic compounds with 2 rings Category:Lactones