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

• -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

• N-arylation of NH groups under metal-free conditions [35][36][37][38][39]. For example, treatment of arenecarboxylic acids and alkanecarboxylic acids with diaryliodonium salts and t-BuOK under toluene refluxing conditions provides the corresponding aryl carboxylates in good yields [40][41]. However

• , it is known that 4-arylcoumarins have antitumor activity [42]. Therefore, the one-pot preparation of 4-arylcoumarins from 3-aryl-2-alkynoic acids via aryl esters and cyclization is attractive and important. Here, as part of our ongoing investigation of the synthetic use of diaryliodonium salts for

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

• 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

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

• diaryliodonium salts by a ring opening/Buchwald-amination cascade using anilines and aliphatic amines as nitrogen-containing substrates. With 5 mol % of Pd(OAc)2 the desired N-arylcarbazoles could be isolated in up to 71% yield. Finally, the corresponding cyclic diarylbromonium derivatives were tested in the

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

• one-pot procedures to diaryliodonium salts known that involve both oxidation and ligand exchange directly from the aryl and iodoarene starting materials. The electrochemical oxidation of an iodoarene in the presence of another arene provides a quite general and simple one-step approach to the

• synthesis of diaryliodonium salts [22]. We describe herein a simple procedure for the flow synthesis of diaryliodonium salts using the electrochemical microreactor device described above. The products were obtained in good yields and only minimal work-up was required after the reaction. The reaction takes

• solvent was then removed, water was added (3 mL) and the iodide was precipitated by addition of KI (166 mg, 1 mmol) to give the diaryliodonium salts 11. Di-p-tolyliodonium iodide (11a) [24] Collection of 3 mL, yield: 100 mg (72%); colourless solid; mp 162–164 °C; 1H NMR (400 MHz, CDCl3) δ 2.27 (s, 6H