Bromo-A3-iodane

Interestingly, Kita and Tohma found that the addition of bromide catalyzes the oxidation of primary and secondary alcohols with iodosylbenzene 18 in water [68]. Use of a catalytic amount of KBr activates 18 and oxidizes alcohols to ketones at room temperature. Salts other than bromide (NaX X = F, Cl, I, Cl04, and N03) do not catalyze the reaction effectively. Iodosylbenzene 18 is depoly-merized by the reaction with KBr and generates a reactive bromo-A3-iodane via ligand exchange [Eq. (34)]. Further ligand exchange with an alcohol, followed by reductive / -elimination induced by intramolecular oxy anion, will explain the facile oxidation. 

We propose a mechanism of carbon-halogen bond-forming ligand coupling of diaryl(halo)-A3-iodanes, which involves a highly polarized apical-equatorial transition state. Ligand coupling mechanism of p-chlorophenyl(p-methyl-phenyl)bromo-A3-iodane 77, which exists as an equilibrium mixture of 77a and... 

Vapor pressure osmometric and spectroscopic studies on the molecular association and dissociation of (Z)-vinyl(bromo)-A3-iodane 130 in chloroform solution indicate the equilibrium formation of the dimer 131 as well as the iodonium ion 129, which is stabilized by the coordination of the solvent chloroform via the hypervalent interaction between the positively charged iodine and a chlorine atom [212]. 

Further evidence for the aggregation of the vinyl(bromo)-A3-iodane 130 to the dimeric form 131 was obtained from FAB mass spectrometry [212]. In the spectrum of FAB-MS of 130a, in addition to the M+ - Br peaks, prominent peaks of 2xM+- Br were observed. Furthermore, when a solution of a 1 1 mixture of... 

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