Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts.

N-Acyl carbazoles can be efficiently produced through a single-step process using amides and cyclic diaryliodonium triflates. This convenient reaction is facilitated by copper iodide in p-xylene, using the commonly found activating ligand diglyme. We have tested this method with a wide range of amides and iodonium triflates, proving its versatility with numerous substrates. Beyond carbazoles, we also produced a variety of other N-heterocycles, such as acridines, phenoxazines, or phenazines, showcasing the robustness of our technique. In a broader sense, this new method creates two C-N bonds simultaneously based on a mono-halogenated starting material, thus allowing heterocycle formation with diminished halogen waste.

Synthesis and Single-Electron Oxidation of Bulky Bis(m-terphenyl)chalcogenides: The Quest for Kinetically Stabilized Radical Cations.

Sterically encumbered bis(m-terphenyl)chalcogenides, (2,6-Mes2 C6 H3 )2 E (E=S, Se, Te) were obtained by the reaction of the chalcogen tetrafluorides, EF4 , with three equivalents of m-terphenyl lithium, 2,6-Mes2 C6 H3 Li. The single-electron oxidation of (2,6-Mes2 C6 H3 )2 Te using XeF2 /K[B(C6 F5 )4 ] afforded the radical cation [(2,6-Mes2 C6 H3 )2 Te][B(C6 F5 )4 ] that was isolated and fully characterized. The electrochemical oxidation of the lighter homologs (2,6-Mes2 C6 H3 )2 E (E=S, Se) was irreversible and impaired by rapid decomposition.

One-Pot Synthesis and Conformational Analysis of Six-Membered Cyclic Iodonium Salts.

Two one-pot procedures for the construction of carbon-bridged diaryliodonium triflates and tetrafluoroborates are described. Strong Brønsted acids enable the effective Friedel-Crafts alkylation with diversely substituted o-iodobenzyl alcohol derivatives, providing diphenylmethane scaffolds, which are subsequently oxidized and cyclized to the corresponding dibenzo[b,e]iodininium salts. Based on NMR investigations and density functional theory (DFT) calculations, we could verify the so-far-undescribed existence of two stable isomers in cyclic iodonium salts substituted with aliphatic side chains in the carbon bridge.

One-Pot Synthesis of Heteroatom-Bridged Cyclic Diaryliodonium Salts.

Two one-pot procedures for the construction of O- and N-bridged diaryliodonium triflates are described. An effective aryne-mediated arylation of o-iodophenols and -sulfonamides provides diarylether and diarylamine intermediates, which are subsequently oxidized and cyclized to the corresponding diaryliodaoxinium and -iodazinium salts. Different derivatizations were applied to demonstrate their capacity as useful building blocks and gain a deeper understanding toward the general reactivity of these underdeveloped but potentially highly useful compounds.