(Diacetoxyiodo)benzene

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(Diacetoxyiodo)benzene
Names
Preferred IUPAC name
Phenyl-λ3-iodanediyl diacetate
Other names
Bis(acetoxy)(phenyl)iodane
Bis(acetato-O)phenyliodine
Bis(acetoxy)iodobenzene (BAIB)
(Diacetoxyiodo)benzene
I,I-Diacetatoiodobenzene
Iodobenzene diacetate
Iodosobenzene I,I-diacetate
Phenyliodine(III) diacetate (PIDA)
Phenyliodo diacetate
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.019.826 Edit this at Wikidata
EC Number
  • 221-808-1
  • InChI=1S/C10H11IO4/c1-8(12)14-11(15-9(2)13)10-6-4-3-5-7-10/h3-7H,1-2H3
    Key: ZBIKORITPGTTGI-UHFFFAOYSA-N
  • CC(=O)OI(C1=CC=CC=C1)OC(=O)C
Properties
C10H11IO4
Molar mass 322.098 g·mol−1
Appearance white powder
Melting point 163–165 °C (325–329 °F; 436–438 K)
reacts
Solubility soluble in acetic acid, acetonitrile, dichloromethane
Structure[1][2]
orthorhombic
Pnn2
a = 15.693(3) Å, b = 8.477(2) Å, c = 8.762(2) Å[2]
T-shaped molecular geometry
Related compounds
Related compounds
 (Bis(trifluoroacetoxy)iodo)benzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

(Diacetoxyiodo)benzene, also known as

hypervalent iodine chemical with the formula C
6H
5I(OCOCH
3)
2. It is used as an oxidizing agent in organic chemistry
.

Preparation

This reagent was originally prepared by Conrad Willgerodt[3] by reacting iodobenzene with a mixture of acetic acid and peracetic acid:[4][5]

C6H5I + CH3CO3H + CH3CO2H → C6H5I(O2CCH3)2 + H2O

PIDA can also be prepared from

glacial acetic acid:[5]

C6H5IO + 2 CH3CO2H → C6H5I(O2CCH3)2 + H2O

More recent preparations direct from

potassium peroxydisulfate[7] as the oxidizing agent:[8]

K2S2O8  → C6H5I(O2CCH3)2 + KI + H2SO4 + KHSO4

The PIDA molecule is termed

phenyl group occupying one of the three equatorial positions of a trigonal bipyramid (lone pairs occupy the other two) and the axial positions occupied by oxygen atoms from the acetate groups. The "T" is distorted in that the phenyl-C to I to acetate-O bond angles are less than 90°.[1] A separate investigation of the crystal structure confirmed that it has orthorhombic crystals in space group Pnn2 and reported unit-cell dimensions in good agreement with the original paper.[1][2] The bond lengths around the iodine atom were 2.08 Å to the phenyl carbon atom and equal 2.156 Å bonds to the acetate oxygen atoms. This second crystal structure determination explained the distortion in the geometry by noting the presence of two weaker intramolecular iodine–oxygen interactions, resulting in an "overall geometry of each iodine [that] can be described as a pentagonal-planar arrangement of three strong and two weak secondary bonds."[2]

Unconventional reactions

One use of PIDA is in the preparation of similar reagents by

(bis(trifluoroacetoxy)iodo)benzene (phenyliodine(III) bis(trifluoroacetate), PIFA) by heating in trifluoroacetic acid:[10][8]

PIFA can be used to carry out the Hofmann rearrangement under mildly acidic conditions,[11] rather than the strongly basic conditions traditionally used.[12][13] The Hofmann decarbonylation of an N-protected asparagine has been demonstrated with PIDA, providing a route to β-amino-L-alanine derivatives.[14]

PIDA is also used in Suárez oxidation, where photolysis of hydroxy compounds in the presence of PIDA and iodine generates cyclic ethers.[15][16][17] This has been used in several total syntheses, such as the total synthesis of (−)-majucin, (−)-Jiadifenoxolane A,[18] and cephanolide A.[19]

References

  1. ^
    doi:10.1107/S0567740877006694
    .
  2. ^
    doi:10.1039/DT9790000854
    .
  3. doi:10.1002/cber.189202502221
    .
  4. doi:10.15227/orgsyn.043.0062
    ; Collected Volumes, vol. 5, p. 660.
  5. ^
    ISBN 9780470842898
    .
  6. PMID 16095332
    .
  7. doi:10.1246/bcsj.80.2213
    .
  8. ^
    ISBN 9781118878651
    .
  9. ISBN 9781118878651
    .
  10. doi:10.15227/orgsyn.066.0132
    ; Collected Volumes, vol. 8, p. 132.
  11. ISBN 9780080977430
    .
  12. doi:10.1002/0471264180.or003.07
    .
  13. ISBN 9781483258683
    .
  14. doi:10.1021/jo9702756
    .
  15. doi:10.1016/S0040-4039(01)90085-1
    .
  16. doi:10.1016/S0040-4039(00)79950-3
    .
  17. doi:10.1016/S0040-4039(00)82887-7
    .
  18. PMID 29148748
    .
  19. S2CID 249314606
    .
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