Description
Bis(pyridine)iodonium tetrafluoroborate is iodinating agent for the selective functionalization of unsaturated compounds; can also mediate C-C bond formation.
Preparation
Bis(pyridine)iodonium tetrafluoroborate is prepared by the reaction of HgO/HBF4-SiO2 with iodine and pyridine in dry CH2Cl2 at rt. Solids are filtered off, and the reagent is isolated by precipitation from CH2Cl2 solution by addition of cold ether, repeating the operation several times until a negative test for mercury(II) is obtained (i.e. absence of precipitation of mercury by treatment of an aliquot with NaBH4/NaOH).
Chemical Properties
Yellow powder
Uses
Bis(pyridine)iodonium tetrafluoroborate is used as mild iodinating and oxidizing reagent. It is also useful for selective iodination of free phenolic groups in tyrosine residues during solid-phase synthesis.
reaction suitability
reagent type: oxidant
storage
Bis(pyridine)iodonium tetrafluoroborate can be safely stored under a nitrogen atmosphere (in the dark at 4 °C) for long periods of time (up to 3 months has been observed) without changing either properties or physical appearance.
Purification Methods
recrystallization from CH2Cl2-CHCl3 (white solid)
