One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

• Natalia Soldatova,
• Pavel Postnikov,
• Olga Kukurina,
• Viktor V. Zhdankin,
• Akira Yoshimura,
• Thomas Wirth and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

• , Park Place, Main Building, Cardiff CF10 3AT, UK 10.3762/bjoc.14.70 Abstract A facile synthesis of diaryliodonium salts utilizing Oxone as versatile and cheap oxidant has been developed. This method shows wide applicability and can be used for the preparation of iodonium salts containing electron

• -donating or electron-withdrawing groups in good yields. In addition, this procedure can be applied to the preparation of symmetric iodonium salts directly from arenes via a one-pot iodination–oxidation sequence. Keywords: diaryliodonium salts; iodine; iodonium; oxidation; Oxone; Introduction

• Diaryliodonium salts, which are also known as diaryl-λ3-iodanes, are widely considered to be an important and practically useful class of hypervalent iodine compounds [1][2][3][4]. Diaryliodonium salts have found broad synthetic application as electrophilic arylating reagents in reactions with various

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• the potential bioactivity of fluorine, an investigation was conducted using various fluorine-containing diaryliodonium salts in order to study and compare their biological activity against human lymphoma U937 cells. Most of the compounds tested are well-known reagents for fluoro-functionalized

• arylation reactions in synthetic organic chemistry, but their biological properties are not fully understood. Herein, after initially investigating 18 fluoro-functionalized reagents, we discovered that the ortho-fluoro-functionalized diaryliodonium salt reagents showed remarkable cytotoxicity in vitro

• . These results led us to synthesize more compounds, previously unknown sterically demanding diaryliodonium salts having a pentafluorosulfanyl (SF5) functional group at the ortho-position, that is, unsymmetrical ortho-SF5 phenylaryl-λ3-iodonium salts. Newly synthesized mesityl(2-(pentafluoro-λ6-sulfanyl

Diels–Alder cycloadditions of N-arylpyrroles via aryne intermediates using diaryliodonium salts

• Huangguan Chen,
• Jianwei Han and
• Limin Wang

Beilstein J. Org. Chem. 2018, 14, 354–363, doi:10.3762/bjoc.14.23

• Synthesis, Shanghai Institute of Organic Chemistry, The Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China 10.3762/bjoc.14.23 Abstract With a strategy of the formation of benzynes by using diaryliodonium salts, a cycloaddition reaction of N-arylpyrroles with benzynes was reported. A

• photosensitive dyes. Keywords: benzyne; cycloaddition; diaryliodonium salts; N-phenylamine; pyrrole; Introduction Pyrrole is a very useful heterocyclic substrate to produce structural attributes of valuable chemicals, functional materials and pharmaceuticals [1][2][3][4][5]. Recently, arylation of pyrrole

• derivatives with diaryliodonium salts for pyrrole–aryl coupling products is generating tremendous academic interest in organic synthesis. In 2012, the Zhang and Yu group reported that sodium hydroxide promoted direct arylation of unprotected pyrroles with diaryliodonium salts at the temperature of 80 °C, the

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• Various 4-aryl-3-bromocoumarins were smoothly obtained in moderate yields in one pot by treating 3-aryl-2-propynoic acids with diaryliodonium triflates and K2CO3 in the presence of CuCl, followed by the reaction with tetrabutylammonium bromide (TBAB) and Na2S2O8. The obtained 3-bromo-4-phenylcoumarin was

• transformed into 4-phenylcoumarin derivatives bearing C–H, C–S, C–N, and C–C bonds at 3-position. Keywords: 3-aryl-2-propynoic acid; bromo-cyclization; coumarin; diaryliodonium triflate; O-phenylation; Introduction Coumarin is a benzo-α-pyrone and one of the typical heterocyclic compounds. The importance of

• -alkynoates with N-bromosuccinimide (NBS) at rt [34], where those reactions proceed via radical spiro-cyclization and then radical 1,2-carboxyl group migration, were reported. On the other hand, diaryliodonium salts are very useful for the C-arylation of active CH groups, the O-arylation of OH groups, and the

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• the corresponding sulfides. Very recently, the same group reported of a controllable sulfenylation and sulfoxidation procedure starting from alkyl and aryl thiosulfates and diaryliodonium salts under visible-light catalysis with Eosin Y (Scheme 40) [75]. They observed that the reaction yields the

• respective sulfides when it is conducted under inert atmosphere, whereas aerobic conditions selectively lead to the respective sulfoxides. They propose a mechanism where first the diaryliodonium salt is photoreduced by the excited-state of Eosin Y, yielding an aryl radical and Eosin Y radical cation

• diaryliodonium salts reacted efficiently with alkyl and aryl thiosulfate salts to the respective sulfide and sulfoxides. A row of functional groups like for example amines, cyano groups, esters, hydroxy groups or nitro groups were highly tolerated and gave the opportunity for late-stage functionalization of

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• conditions, as shown in Scheme 3 (left). By contrast, the Daugulis group and others [173][174] have demonstrated Pd-catalyzed ortho-arylations of anilides at temperatures typically greater than 100 °C, and the Sanford group has also studied similar transformations involving diaryliodonium salts [175

• silver salt and HBF4 (or in situ generated AgBF4). The specific nature of the reaction between the palladacycle and aryl iodide and resulting intermediate is lacking in details. It is known that divalent palladacycles react with alkyl iodides or diaryliodonium salts, and this process likely involves a Pd

Pyridylidene ligand facilitates gold-catalyzed oxidative C–H arylation of heterocycles

• Kazuhiro Hata,
• Hideto Ito,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2015, 11, 2737–2746, doi:10.3762/bjoc.11.295

• yields than IBA mainly due to the formation of diaryliodonium PhI(4-BrC6H4)+ produced by the reaction with arylsilane 2a (Table 1, entries 4–6) [69]. Using p-toluenesulfonic acid (TsOH) instead of CSA was less effective (Table 1, entry 7). It was clearly seen that both CSA and methanol had a significant

A concise and efficient synthesis of benzimidazo[1,2-c]quinazolines through CuI-catalyzed intramolecular N-arylations

• Xinlong Pang,
• Chao Chen,
• Ming Li and
• Chanjuan Xi

Beilstein J. Org. Chem. 2015, 11, 2365–2369, doi:10.3762/bjoc.11.258

• -cyanoaniline (1) and diaryliodonium salts 2 based on our previously published method [13][14] (Scheme 1). Results and Discussion During the study of the synthesis of various carbocycles or heterocycles with copper catalysts [13][14][15][16][17], we found an interesting tandem reaction of o-cyanoanilines 1 and

• diaryliodonium salts 2 to produce quinazolin-4(3H)-imine derivatives 3 with Cu(OTf)2 as the catalyst [13]. Encouraged by this finding, we initially attempted the reaction of o-cyanoaniline (1a) with di-(o-bromophenyl)iodonium salt 2. The reaction of 2 equiv of o-cyanoaniline (1a) with 2 in DCE at 110 °C for 6 h

Coupling of C-nitro-NH-azoles with arylboronic acids. A route to N-aryl-C-nitroazoles

• Marta K. Kurpet,
• Aleksandra Dąbrowska,
• Małgorzata M. Jarosz,
• Katarzyna Kajewska-Kania,
• Nikodem Kuźnik and
• Jerzy W. Suwiński

Beilstein J. Org. Chem. 2013, 9, 1517–1525, doi:10.3762/bjoc.9.173

• . The presence of the nitro group (a strong electron-withdrawing substituent) in the azole entails the adjustment of the conditions of N-arylation reaction. Besides a very recently published approach involving N-arylation of nitroazoles with diaryliodonium salts [20], already described methods utilize

• of coupling of diaryliodonium salts with 3-nitro-1H-pyrazole [20], a product of Ullman phenylation of 3-nitro-1H-pyrazole [34], or a byproduct in the synthesis of 1-phenyl-4-amino-5-methylaminopyridazin-6-one [17] (Scheme 1). Although these works describe 3-nitro-1-phenyl-1H-pyrazole (3a) as the

• et al. [20], it appears that both methods are regioselective and lead to syntheses of N-aryl-C-nitroazoles in moderate to high yields. Arylboronic acids are more easily available than diaryliodonium salts, and thus the scope of our approach seems to be wider. The much milder reaction conditions

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

• Stefan Riedmüller and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

• with a concurrent nucleophilic counterion [26]. However, 1 was synthesized from 2-iodobiphenyl according to the established one-pot procedure for the synthesis of diaryliodonium triflates [27][28] by Olofsson and co-workers (Supporting Information File 1). After promising initial experiments, we

• decomposition pathways of the diaryliodonium salt (2-iodobiphenyl, 2,2'-diiodobiphenyl, and 2-(2,5-dimethylphenyl)-2'-iodobiphenyl) [29][30][31]. To further verify these observations, we reacted 1 in the presence of aniline (2a) for three days at elevated temperature without adding a Pd catalyst. Again, after

• reacted 6 with p-fluoroaniline (2f) according to our previously described optimized conditions (Scheme 4). However, 3f was obtained in only 25% yield (Scheme 4), compared to 71% when using the corresponding diaryliodonium salt 1 (Figure 3). Apart from the desired product, we were able to isolate two

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• different reactions can be carried out successfully using simple protocols. Keywords: diaryliodonium compounds; electrochemistry; flow chemistry; microreactor; Introduction Electrochemical reactions offer a clean route to the formation of anion and cation radical species from neutral organic molecules

• the continuous synthesis of diaryliodonium compounds. A microflow electrochemical reactor made out of two aluminium bodies (50 mm diameter, 25 mm height) was manufactured. The electrodes are constructed of two PTFE plates (35 mm diameter, 4 mm height) onto which 0.1 mm platinum foil electrodes [16

• deficient nature and high dissociation rates that make them excellent leaving groups. Symmetric salts are usually more desirable than asymmetric compounds purely for the reason that this avoids problems that can occur with selectivity in aryl-transfers. If a diaryliodonium salt is asymmetric it is usually