(Bis(trifluoroacetoxy)iodo)benzene
Names
Preferred IUPAC name
Phenyl-λ3 -iodanediyl bis(trifluoroacetate)
Other names
Phenyliodine bis(trifluoroacetate); PIFA
Identifiers
ChemSpider
ECHA InfoCard 100.018.462
EC Number
UNII
InChI=1S/C10H5F6IO4/c11-9(12,13)7(18)20-17(6-4-2-1-3-5-6)21-8(19)10(14,15)16/h1-5H
Y Key: PEZNEXFPRSOYPL-UHFFFAOYSA-N
Y InChI=1/C10H5F6IO4/c11-9(12,13)7(18)20-17(6-4-2-1-3-5-6)21-8(19)10(14,15)16/h1-5H
Key: PEZNEXFPRSOYPL-UHFFFAOYAA
FC(F)(F)C(=O)OI(OC(=O)C(F)(F)F)c1ccccc1
Properties
C 10 H 5 F 6 I O 4
Molar mass
−1
Hazards
GHS labelling
Warning
H315 , H319 , H335
P261 , P264 , P271 , P280 , P302+P352 , P304+P340 , P305+P351+P338 , P312 , P321 , P332+P313 , P337+P313 , P362 , P403+P233 , P405 , P501
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
Chemical compound
(Bis(trifluoroacetoxy)iodo)benzene , C6 5 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
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]
It can also be prepared by dissolving diacetoxyiodobenzene (a commercially-available compound) with heating in trifluoroacetic acid:[ 2]
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]
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] Organic Syntheses cyclobutanecarboxamide , easily synthesized from cyclobutylcarboxylic acid , to cyclobutylamine .[ 2] primary amine is initially present as its trifluoroacetate salt , which can be converted to the hydrochloride salt to facilitate product purification.[ 1] [ 2]
References
^ 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. Vol. 6. pp. 598– 635. doi :10.1016/B978-0-08-097742-3.00623-6 . ISBN 9780080977430 ^ 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" . Organic Syntheses 66 : 132. doi :10.15227/orgsyn.066.0132 Collected Volumes , vol. 8, p. 132^ Wallis, Everett S.; Lane, John F. (1946). "The Hofmann Reaction". Organic Reactions 3 (7): 267– 306. doi :10.1002/0471264180.or003.07 . ^ Surrey, Alexander R. (1961). "Hofmann Reaction" . Name Reactions in Organic Chemistry (2nd ed.). Academic Press . pp. 134– 136. ISBN 9781483258683
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