(Bis(trifluoroacetoxy)iodo)benzene

Last updated
(Bis(trifluoroacetoxy)iodo)benzene
(bis(trifluoroacetoxy)iodo)benzene.png
(bis(trifluoroacetoxy)iodo)benzene-3D-balls.png
Names
IUPAC name
phenyl{bis[(trifluoroacetyl)oxy]}-λ3-iodane
Other names
Phenyliodine bis(trifluoroacetate); PIFA
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.018.462
EC Number
  • 220-308-0
PubChem CID
UNII
Properties
C10H5F6IO4
Molar mass 430.041 g·mol−1
Hazards
GHS pictograms GHS-pictogram-exclam.svg
GHS Signal word Warning
H315, H319, H335
P261, P264, P271, P280, P302+352, P304+340, P305+351+338, P312, P321, P332+313, P337+313, P362, P403+233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)
Infobox references

(Bis(trifluoroacetoxy)iodo)benzene, C
6
H
5
I(OCOCF
3
)
2
, is a hypervalent iodine compound used as a reagent in organic chemistry. It can be used to carry out the Hofmann rearrangement under acidic conditions. [1]

Contents

Preparation

The syntheses of all aryl hypervalent iodine compounds start from iodobenzene. The compound can be prepared by reaction of iodobenzene with a mixture of trifluoroperacetic acid and trifluoroacetic acid in a method analogous to the synthesis of (diacetoxyiodo)benzene: [1]

PIFA synthesis by oxidation.png

It can also be prepared by dissolving diacetoxyiodobenzene (a commercially-available compound) with heating in trifluoroacetic acid: [2]

PIFA synthesis by exchange.png

Uses

It also brings around the conversion of a hydrazone to a diazo compound, for example in the diazo-thioketone coupling. It also converts thioacetals to their parent carbonyl compounds.

Hofmann rearrangement

The Hofmann rearrangement is a decarbonylation reaction whereby an amide is converted to an amine by way of an isocyanate intermediate. It is usually carried out under strongly basic conditions. [3] [4]

Hofmann Rearrangement Scheme.png

The reaction can also be carried out under mildly acidic conditions by way of the same intermediate using a hypervalent iodine compound in aqueous solution. [1] An example published in Organic Syntheses is the conversion of cyclobutanecarboxamide, easily synthesized from cyclobutylcarboxylic acid, to cyclobutylamine. [2] The primary amine is initially present as its trifluoroacetate salt, which can be converted to the hydrochloride salt to facilitate product purification. [1] [2]

Cyclobutanecarboxamide Hofmann rearrangement.png

Related Research Articles

Imine any chemical compound having the structure RN=CR′R″, thus analogue of aldehyde or ketone in which an oxygen atom is replaced by substituted or unsubstituted nitrogen atom

An imine is a functional group or chemical compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen (H) or an organic group (R). If this group is not a hydrogen atom, then the compound can sometimes be referred to as a Schiff base. The carbon atom has two additional single bonds. The term "imine" was coined in 1883 by the German chemist Albert Ladenburg.

The diazogroup is an organic moiety consisting of two linked nitrogen atoms (azo) at the terminal position. Overall charge neutral organic compounds containing the diazo group bound to a carbon atom are called diazo compounds or diazoalkanes and are described by the general structural formula R2C=N+=N. The simplest example of a diazo compound is diazomethane, CH2N2. Diazo compounds (R2C=N2) should not be confused with azo compounds of the type R-N=N-R or with diazonium compounds of the type R-N2+.

The Hofmann rearrangement is the organic reaction of a primary amide to a primary amine with one fewer carbon atom.

Diazonium compound diazonium salts

Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group R−N+
2
X
where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halogen.

2-Iodoxybenzoic acid chemical compound

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 prepared from 2-iodobenzoic acid, potassium bromate, and sulfuric acid. Frigerio and co-workers have also demonstrated, in 1999 that potassium bromate may be replaced by commercially available Oxone. One of the main drawbacks of IBX is its limited solubility; IBX is insoluble in many common organic solvents. In the past, it was believed that IBX was shock sensitive, but it was later proposed that samples of IBX were shock sensitive due to the residual potassium bromate left from its preparation. Commercial IBX is stabilized by carboxylic acids such as benzoic acid and isophthalic acid.

In organic chemistry, the Arndt–Eistert reaction is the conversion of a carboxylic acid to its homologue. Named for the German chemists Fritz Arndt (1885–1969) and Bernd Eistert (1902–1978), the method entails treating an acid chlorides with diazomethane. It is a popular method of producing β-amino acids from α-amino acids.

The Barton–Kellogg reaction is a coupling reaction between a diazo compound and a thioketone, giving an alkene by way of an episulfide intermediate. The Barton–Kellogg reaction is also known as Barton–Kellogg olefination and Barton olefin synthesis.

Di-<i>tert</i>-butyl dicarbonate chemical compound

Di-tert-butyl dicarbonate is a reagent widely used in organic synthesis. Since this compound can be regarded formally as the acid anhydride derived from a tert-butoxycarbonyl (Boc) group, it is commonly referred to as Boc anhydride. This pyrocarbonate reacts with amines to give N-tert-butoxycarbonyl or so-called Boc derivatives. These carbamate derivatives do not behave as amines, which allows certain subsequent transformations to occur that would be incompatible with the amine functional group. The Boc group can later be removed from the amine using moderately strong acids. Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an orthogonal protecting group.

The Lossen rearrangement is the conversion of a hydroxamate ester to an isocyanate. Typically O-acyl, sulfonyl, or phosphoryl O-derivative are employed.The isocyanate can be used further to generate ureas in the presence of amines or generate amines in the presence of H2O.

Wolff rearrangement

The Wolff rearrangement is a reaction in organic chemistry in which an α-diazocarbonyl compound is converted into a ketene by loss of dinitrogen with accompanying 1,2-rearrangement. The Wolff rearrangement yields a ketene as an intermediate product, which can undergo nucleophilic attack with weakly acidic nucleophiles such as water, alcohols, and amines, to generate carboxylic acid derivatives or undergo [2+2] cycloaddition reactions to form four-membered rings. The mechanism of the Wolff rearrangement has been the subject of debate since its first use. No single mechanism sufficiently describes the reaction, and there are often competing concerted and carbene-mediated pathways; for simplicity, only the textbook, concerted mechanism is shown below. The reaction was discovered by Ludwig Wolff in 1902. The Wolff rearrangement has great synthetic utility due to the accessibility of α-diazocarbonyl compounds, variety of reactions from the ketene intermediate, and stereochemical retention of the migrating group. However, the Wolff rearrangement has limitations due to the highly reactive nature of α-diazocarbonyl compounds, which can undergo a variety of competing reactions.

Iodobenzene chemical compound

Iodobenzene is an organoiodine compound consisting of a benzene ring substituted with one iodine atom. It is useful as a synthetic intermediate in organic chemistry. It is a volatile colorless liquid, although aged samples appear yellowish.

Anthranilic acid chemical compound

Anthranilic acid is an aromatic acid with the formula C6H4(NH2)(CO2H) and has a sweetish taste. The molecule consists of a benzene ring, ortho-substituted with a carboxylic acid and an amine. As a result of containing both acidic and basic functional groups, the compound is amphoteric. Anthranilic acid is a white solid when pure, although commercial samples may appear yellow. The anion [C6H4(NH2)(CO2)], obtained by the deprotonation of anthranilic acid, is called anthranilate. Anthranilic acid was once thought to be a vitamin and was referred to as vitamin L1 in that context, but it is now known to be non-essential in human nutrition.

Lead(IV) acetate chemical compound

Lead(IV) acetate or lead tetraacetate is a chemical compound with chemical formula Pb(C2H3O2)4. It is a colorless solid that is soluble in nonpolar organic solvents, indicative that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis.

Oseltamivir total synthesis

Oseltamivir total synthesis concerns the total synthesis of the antiinfluenza drug oseltamivir marketed by Hoffmann-La Roche under the trade name Tamiflu. Its commercial production starts from the biomolecule shikimic acid harvested from Chinese star anise with a limited worldwide supply. Due to its limited supply, searches for alternative synthetic routes preferably not requiring shikimic acid are underway and to date several such routes have been published. Control of stereochemistry is important: the molecule has three stereocenters and the sought-after isomer is only 1 of 8 stereoisomers.

The Hofmann–Löffler reaction (also referred to as Hofmann–Löffler–Freytag reaction, Löffler–Freytag reaction, Löffler–Hofmann reaction, as well as Löffler's method) is an organic reaction in which a cyclic amine 2 (pyrrolidine or, in some cases, piperidine) is generated by thermal or photochemical decomposition of N-halogenated amine 1 in the presence of a strong acid (concentrated sulfuric acid or concentrated CF3CO2H). The Hofmann–Löffler–Freytag reaction proceeds via an intramolecular hydrogen atom transfer to a nitrogen-centered radical and is an example of a remote intramolecular free radical C–H functionalization.

Iodane generally refers to any organic derivative of iodine. Without modifier, iodane is the systematic name for the parent hydride of iodine, HI. Thus, any organoiodine compound with general formula RI (e.g., CH3I or C6H5I) is a substituted iodane. However, as used in the context of organic synthesis, the term iodane more specifically refers to organoiodine compounds with nonstandard bond number (i.e., bond number greater than one), making this term a synonym for hypervalent iodine. These iodine compounds are hypervalent because the iodine atom formally contains more than the 8 electrons in the valence shell required for the octet rule. When iodine is ligated to an organic residue and electronegative ligands (e.g. halides or carboxylates), hypervalent iodine compounds occur with a +3 oxidation number as iodine(III) or λ3-iodanes or as a +5 oxidation number as iodine(V) or λ5-iodanes. (Here, lambda convention is used to give the nonstandard bond number.)

Imidazole-1-sulfonyl azide chemical compound

Imidazole-1-sulfonyl azide is an organic azide compound that can be used as an alternative to trifluoromethanesulfonyl azide. It is an explosive colorless liquid, but some of its organic-soluble salts can be safely handled and stored as a solid.

Carbonyl oxidation with hypervalent iodine reagents involves the functionalization of the α position of carbonyl compounds through the intermediacy of a hypervalent iodine(III) enolate species. This electrophilic intermediate may be attacked by a variety of nucleophiles or undergo rearrangement or elimination.

Trifluoroperacetic acid chemical compound

Trifluoroperacetic acid is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the condensed structural formula CF
3
COOOH
. It is a strong oxidizing agent for organic oxidation reactions, such as in Baeyer–Villiger oxidations of ketones. It is the most reactive of the organic peroxy acids, allowing it to successfully oxidise relatively unreactive alkenes to epoxides where other peroxy acids are ineffective. It can also oxidise the chalcogens in some functional groups, such as by transforming selenoethers to selones. It is a potentially explosive material and is not commercially available, but it can be quickly prepared as needed. Its use as a laboratory reagent was pioneered and developed by William D. Emmons.

(Diacetoxyiodo)benzene chemical compound

(Diacetoxyiodo)benzene, also known as phenyliodine(III) diacetate (PIDA) is a hypervalent iodine chemical with the formula C
6
H
5
I(OCOCH
3
)
2
. It is used as an oxidizing agent in organic chemistry.

References

  1. 1 2 3 4 Aubé, Jeffrey; Fehl, Charlie; Liu, Ruzhang; McLeod, Michael C.; Motiwala, Hashim F. (1993). "6.15 Hofmann, Curtius, Schmidt, Lossen, and Related Reactions". Heteroatom Manipulations. Comprehensive Organic Synthesis II. 6. pp. 598–635. doi:10.1016/B978-0-08-097742-3.00623-6. ISBN   9780080977430.
  2. 1 2 3 Almond, M. R.; Stimmel, J. B.; Thompson, E. A.; Loudon, G. M. (1988). "Hofmann Rearrangement Under Mildly Acidic Conditions Using [I,I-Bis(Trifluoroacetoxy)]Iodobenzene: Cyclobutylamine Hydrochloride from Cyclobutanecarboxamide". Organic Syntheses . 66: 132. doi:10.15227/orgsyn.066.0132.; Collective Volume, 8, p. 132
  3. Wallis, Everett S.; Lane, John F. (1946). "The Hofmann Reaction". Organic Reactions . 3 (7): 267–306. doi:10.1002/0471264180.or003.07.
  4. Surrey, Alexander R. (1961). "Hofmann Reaction". Name Reactions in Organic Chemistry (2nd ed.). Academic Press. pp. 134–136. ISBN   9781483258683.