Trivalent Iodine Heterocycles

Structural assignment was not reliable. The first readily available benzioda-zole derivative, acetoxybenziodazole (53, Y = OAc, Z = H), was synthesized in 1965 by the peracetic acid oxidation of 2-iodobenzamide (1965CC449). 

A stable aliphatic iodoxolone 73, the tautomer of d5-2-iodosylcyclopro-panecarboxylic acid, has been prepared by two alternative methods the 

AcOOH/AcOH (81% yield) or KBr03/H2S04 (87% yield) -CO2  

AcOOH/AcOH (25% yield) or mCPBA, AC2O (50% yieldr 

Compound 73 exists in the hydroxyiodoxolone form, not in the open ri5-2-iodosylcyclopropanecarboxylic acid fonn, as indicated by its low-acidity (pKa 7.55) and by its ability to cleave phosphate esters in aqueous micellar solution (see Section 3.2.2.2 1989JA6729). 

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A series of heterocyclic compounds containing trivalent iodine, oxygen and boron in a five-membered ring has been prepared by oxidative cyclization of commercially available orf/to-iodophenylboronic acids 182 and 185... 

The noncyclic CF3-substituted trivalent iodine derivatives lack stability and cannot be isolated at room temperature however, the incorporation of a hypervalent iodine atom into a five-membered heterocycle has a significant stabilization efiect. The synthesis of stable trifluoromethylbenziodoxoles 141 and 143—145 by treatment of the corresponding methoxybenziodoxole... 

Several heterocyclic compounds containing trivalent iodine, oxygen, and boron in a five-membered ring have been prepared by oxidative cyclization of the orifco-iodophenylboronic acids 168 and 171 (201IICI1263). 1-Chloro-4-fluoro-lH-lX -benzo[(/][l,2,3]iodoxaborol-3-ol 170 was formed in the reaction of 2-fluoro-6-iodophenylboronic acid 168 with chlorine followed by treatment of the intermediate iododichloride 169 with water. The... 

Togo, H., Aoki, M., and Yokoyama, M., Facile radical decarboxylative alkylation of heteroaromatic bases using carboxylic acids and trivalent iodine compounds, Tetrahedron Lett., 32, 6559, 1991. Togo, H., Aoki, M., and Yokoyama, M., Alkylation of aromatic heterocycles with oxalic acid monoalkyl esters in the presence of trivalent iodine compounds, Chem. Lett., 1691,1991. Vismara, E., Torri, G., Pastori, N., and Marchiandi, M., A new approach to the stereoselective synthesis of C-nucleosides via homolytic heteroaromatic substitution. Tetrahedron Lett., 33, 7575, 1992. 

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