The PIDA molecule is termed
hypervalent as its iodine atom (technically a
hypervalent iodine) is in its +III
oxidation state and has more than typical number of
covalent bonds.[9] It adopts a
T-shaped molecular geometry, with the
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]
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]
^
abcdAlcock, Nathaniel W.; Countryman, Rachel M.; Esperås, Steinar; Sawyer, Jeffery F. (1979). "Secondary bonding. Part 5. The crystal and molecular structures of phenyliodine(III) diacetate and bis(dichloroacetate)". J. Chem. Soc., Dalton Trans.1979 (5): 854–860.
doi:
10.1039/DT9790000854.
^Hossain, Md. Delwar; Kitamura, Tsugio (2005). "Unexpected, Drastic Effect of Triflic Acid on Oxidative Diacetoxylation of Iodoarenes by Sodium Perborate. A Facile and Efficient One-Pot Synthesis of (Diacetoxyiodo)arenes". J. Org. Chem.70 (17): 6984–6986.
doi:
10.1021/jo050927n.
PMID16095332.
^Hossain, Md. Delwar; Kitamura, Tsugio (2007). "New and Direct Approach to Hypervalent Iodine Compounds from Arenes and Iodine. Straightforward Synthesis of (Diacetoxyiodo)arenes and Diaryliodonium Salts Using Potassium μ-Peroxo-hexaoxodisulfate". Bull. Chem. Soc. Jpn.80 (11): 2213–2219.
doi:
10.1246/bcsj.80.2213.
^Zhang, Lin-hua; Kauffman, Goss S.; Pesti, Jaan A.; Yin, Jianguo (1997). "Rearrangement of Nα-Protected L-Asparagines with Iodosobenzene Diacetate. A Practical Route to β-Amino-L-alanine Derivatives". J. Org. Chem.62 (20): 6918–6920.
doi:
10.1021/jo9702756.
^Concepción, José I.; Francisco, Cosme G.; Hernández, Rosendo; Salazar, José A.; Suárez, Ernesto (1984). "Intramolecular hydrogen abstraction. Iodosobenzene diacetate, an efficient and convenient reagent for alkoxy radical generation". Tetrahedron Letters. 25 (18): 1953–1956.
doi:
10.1016/S0040-4039(01)90085-1.
^Courtneidge, John L.; Lusztyk, Janusz; Pagé, Daniel (1994). "Alkoxyl radicals from alcohols. Spectroscopic detection of intermediate alkyl and acyl hypoiodites in the Suárez and Beebe reactions". Tetrahedron Letters. 35 (7): 1003–1006.
doi:
10.1016/S0040-4039(00)79950-3.
^Dorta, R. L.; Francisco, C.G.; Freire, R.; Suárez, E. (1988). "Intramolecular hydrogen abstraction. The use of organoselenium reagents for the generation of alkoxy radicals". Tetrahedron Letters. 29 (42): 5429–5432.
doi:
10.1016/S0040-4039(00)82887-7.