(Bis(trifluoroacetoxy)iodo)benzene

From Wikipedia, the free encyclopedia
Jump to: navigation, search
(Bis(trifluoroacetoxy)iodo)benzene
(bis(trifluoroacetoxy)iodo)benzene.png
(bis(trifluoroacetoxy)iodo)benzene-3D-balls.png
Names
Other names
Phenyliodine bis(trifluoroacetate); PIFA
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.018.462
Properties
C10H5F6IO4
Molar mass 430.04 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
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]

Preparation[edit]

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[edit]

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[edit]

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

References[edit]

  1. ^ a b c d 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. 
  2. ^ a b c 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". Org. Synth. 66: 132. doi:10.15227/orgsyn.066.0132. ; Coll. Vol., 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.