Session: New Reactions & Methodology:

The acid activation of phenyliodonium diacetate (PIDA) with trimethylsilyl triflate (TMSOTf) is investigated toward the goal of elucidating the mechanism from calculated energies of relevant intermediates. The computational study of the activation of PIDA is applicable in the transmetallation of hypervalent iodine compounds in iodine-guided reactions including the hypervalent iodine-guided electrophilic substitution (HIGES) reaction. The HIGES reaction provides a principle for selective bond formations including the Reductive Iodonio-Claisen Rearrangement (RICR) and the para-selective benzylation of aryl-λ³-iodane diacetates. One disadvantage of the previously reported HIGES para-selective benzylation is the preparation and isolation of hypervalent iodine starting materials. An alternative approach is reported herein in which the para-selective benzylated product is afforded through the fluorination of iodoarenes via an in-situ oxidation reaction. The novel in-situ method of preparing (difluoro)iodoarenes for the HIGES reaction is economically favorable in that the C-C bond formation occurs while retaining the iodo-aryl bond. The metal-like properties of hypervalent iodine allow for a transmetallation with metalloid reactants upon activation with Lewis acids and are further explored in novel transformations of reactions between Grignard and hypervalent iodine reagents.

Nirvanie Singh

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