Categories: C-I Bond Formation >
Synthesis of iodonium salts and related compounds
A new, regiospecific, sequential one-pot synthesis of symmetrical and unsymmetrical diaryliodonium tetrafluoroborates, which are the most popular salts in metal-catalyzed arylations, is fast and high-yielding and has a large substrate scope. Furthermore, the corresponding diaryliodonium triflates can conveniently be obtained via an in situ anion exchange.
M. Bielawski, D. Aili, B. Olofsson, J. Org. Chem., 2008, 73, 4602-4607.
Stoichiometric quantities of trifluoroacetic acid and trimethoxybenzene can be used as the counteranion and auxiliary precursors for a direct synthesis of aryl(2,4,6-trimethoxyphenyl)iodonium trifluoroacetate salts from aryl iodides under oxidizing conditions. The reaction occurs at mild temperature, is broad in scope, and does not require a separate anion exchange step to install the trifluoroacetate group.
V. Carreras, A. H. Sandtorv, D. R. Stuart, J. Org. Chem., 2017, 82, 1279-1284.
A one-pot synthesis of aryl(2,4,6-trimethoxyphenyl)iodonium salts from aryl iodides, m-CPBA, p-toluenesulfonic acid, and trimethoxybenzene is fast, provides a high yield of product, and has broad substrate scope. The utility of these reagents is demonstrated in arylation reactions with C-, N-, O-, and S-nucleophiles.
T. L. Seidl, S. K. Sundalam, B. McCullough, D. R. Stuart, J. Org. Chem., 2016, 81, 1998-2009.
A simple and easy method for the synthesis of various iodonium salts involves the reaction of potassium organotrifluoroborates with p-iodotoluene difluoride under mild conditions.
T. Fukuhara, C. Hasegawa, S. Hara, Synthesis, 2007, 1542-1546
A direct synthesis of symmetric and unsymmetric electron-rich diaryliodonium salts delivers diaryliodonium tosylates in high yields using MCPBA and toluenesulfonic acid. An in situ anion exchange has also been developed, giving access to the corresponding triflate salts.
M. Zhu, N. Jalalian, B. Olofsson, Synlett, 2008, 592-596.
Ethynylbenziodoxolones (EBXs) are useful reagents for the electrophilic alkynylation of nucleophiles. One-pot, two-step processes for EBX generation and their direct reaction with two- and one-electron nucleophiles even allow to bypass the originally mandatory isolation and purification of the reagents, resulting in more efficient syntheses of alkynylated products.
J. Borrel, J. Waser, Org. Lett., 2022, 24, 142-146.
Phenyliodonium ylides provide easy access to various 1,1-cyclopropane diesters using rhodium or copper catalysis and are safer and convenient alternatives to the corresponding diazo compounds. Moreover, the iodonium ylide of dimethyl malonate was obtained in 78% yield using improved conditions that involve a simple filtration step to isolate the desired product.
S. R. Goudreau, D. Marcoux, A. B. Charette, J. Org. Chem., 2009, 74, 470-473.