An interesting bit of chemistry was published by Berit Olofsson at Stockholm University in a recent JOC. The Olofsson lab has previously produced a method for the one-pot preparation of diaryliodonium triflates. This latest work provides diaryliodonium tetrafluoroborates (JOC, 2008, 73, 4602-4607). 

The preparation of I(III) compounds usually starts with an Ar-I compound undergoing oxidation followed by an electrophilic addition/substitution to another arene. Regioselectivity is obtained by choosing a donor with a leaving group such as a boronic acid, stannane, or silane.

What is clever about this process is the fact that a BF4 salt is directly produced. Two equivalents of boron trifluoride etherate are used in the reaction which evidently results in some kind of disproportionation producing the BF4 counter-anion. 

It is known that the reactivity of iodonium compounds is somewhat sensitive to the coordinating ability of the counter-anion, so BF4 is less undesirable than other choices (like chloride). Solubility is greatly influenced by the choice of counter-anion as well. This is particularly true in photo-initiator applications where the choice of carrier fluid may be limited.

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