Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• phenanthrenes 54 in moderate to good yields (Scheme 19) [59]. Indoles also are relevant substrates for the tandem arylation with cyclic diaryl-λ3-iodanes, allowing the preparation of dibenzocarbazoles 55 in moderate yields (Scheme 20) [60]. The reaction is catalyzed simply by Pd(OAc)2 in the absence of any

• reductive elimination. Starting from the ortho-N-(acyl)diaryl-λ3-iodanes 57, a combination of copper and palladium catalysis, in the presence of a phosphine ligand, induces the internal O-arylation of the proximal amide moiety, followed by a subsequent metal-catalyzed coupling-reaction with the resulting Ar

• high yielding N-arylation of 1H-1,2,3-benzotriazole (BTA), utilizing symmetrical diaryl-λ3-iodanes as two-fold aryl donors has been reported in the presence of Pd(OAc)2 and TPPTS as a water-soluble ligand, and copper(II) phenylcyclopropylcarboxylate (Scheme 35) [74]. Noteworthy, it is mentioned that Ar

Metal-free formal synthesis of phenoxazine

• Gabriella Kervefors,
• Antonia Becker,
• Chandan Dey and
• Berit Olofsson

Beilstein J. Org. Chem. 2018, 14, 1491–1497, doi:10.3762/bjoc.14.126

• a high-yielding O-arylation of a phenol with an unsymmetrical diaryliodonium salt to provide an ortho-disubstituted diaryl ether. This species was cyclized to acetylphenoxazine in moderate yield. The overall yield in the three-step sequence is 72% based on recovered diaryl ether. An interesting

• , unusually stable iodine(III) intermediate in the O-arylation was observed by NMR and could be converted to the product upon longer reaction time. Keywords: arylation; cyclization; diaryl ether; diaryliodonium salt; phenol; Introduction Phenoxazine (1) is a tricyclic compound consisting of an oxazine ring

• [17][19][20]. A Pd-catalyzed double N-arylation using di(2-bromoaryl) ethers and primary amines was recently developed (Scheme 1c) [21]. Furthermore, N-functionalization of the phenoxazine core can be performed under metal-free conditions [22]. Our research group has reported highly efficient O

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• arylation protocols [18][19][20][21][22]. While in solid state they clearly have a T-shaped pseudotrigonal bipyramid structure, the common structural motif for λ3-iodanes, recent theoretical investigations revealed a potential role of the cationic, normal valent tetrahedral form, in atom transfer processes

• waste. Examples for their atom-economical utilization, in which at least both aryl ligands are transferred, are still rare. A general approach would involve at first a metal-catalysed or metal-free arylation step of a suitable substrate A with the diaryliodonium salt 1 to give monoarylated intermediate

• –boron bond formation gives one equivalent of arylboronic ester 4 and an iodoarene 2 through a metal-free boron arylation. Subsequent cross coupling under Suzuki conditions affords symmetrical biphenyls 3’ in good yields. Due to the temporary introduction and cleavage of the boron moiety the formal atom

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• more effective chiral iodonium salts 16 which were used for the α-arylation of β-ketoester 86 to deliver α-arylated β-ketoesters 87 with moderate enantioselectivity (Scheme 17) [63]. This was the first example of an asymmetric α-arylation of β-ketoesters using hypervalent iodine reagents. A more

• different stereoelectronic properties by using aliphatic alcohols as a sole source of chirality [64]. Olofsson and Wirth et al. also jointly reported the synthesis of new structurally distinct chiral reagents 20 considering their interest towards asymmetric metal-free arylation [65]. In 1997, Wirth et al

• diamination of alkenes. Stereoselective oxyamination of alkenes reported by Wirth et al. Enantioselective and regioselective aminofluorination by Nevado et al. Fluorinated difunctionalization reported by Jacobsen et al. Aryl rearrangement reported by Wirth et al. α-Arylation of β-ketoesters. Asymmetric α

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

• Anna Czarnecka,
• Emilia Kowalska,
• Agnieszka Bodzioch,
• Joanna Skalik,
• Marek Koprowski,
• Krzysztof Owsianik and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105

• -coupling reactions of substrates containing an 1,3-dithiane moiety are feasible, like in the case of the 2-arylation of 2-aryl-substituted 1,3-dithianes. However, in the case of 2-benzyl-substituted 1,3-dithianes, a tandem elimination/1,3-dithiane ring opening followed by a Pd-catalyzed C−S bond formation

Imide arylation with aryl(TMP)iodonium tosylates

• Souradeep Basu,
• Alexander H. Sandtorv and
• David R. Stuart

Beilstein J. Org. Chem. 2018, 14, 1034–1038, doi:10.3762/bjoc.14.90

• -deficient and sterically encumbered aryl groups. Keywords: arylation; C–N coupling; diaryliodonium; hypercoordinate iodine; metal-free; Introduction Imides are important structural units in a range of approved pharmaceuticals and agrochemicals (Scheme 1a) [1]. Despite the general prevalence of imides, N

• Discussion We initiated our optimization of the arylation of the potassium phthalimide nucleophile with diaryliodonium electrophiles by surveying several reaction conditions: dummy ligand (Aux), counter anion, solvent and volume, reaction temperature, and stoichiometry (Table 1). Consistent with an

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• syntheses [17][18][19][20][21][22][23][24][25][26][27][28]. Tuning of the electrochemical potential of substituted ferrocenium salts promoted a selective oxidative bicyclization reaction under mild conditions (Scheme 1a) [27]. Ferrocene and decamethylferrocene act as redox catalysts in Meerwein arylation

The first Pd-catalyzed Buchwald–Hartwig aminations at C-2 or C-4 in the estrone series

• Ildikó Bacsa,
• Dávid Szemerédi,
• János Wölfling,
• Gyula Schneider,
• Lilla Fekete and
• Erzsébet Mernyák

Beilstein J. Org. Chem. 2018, 14, 998–1003, doi:10.3762/bjoc.14.85

• the presence of X-Phos or BINAP as ligands. The literature data influenced the selection of the base. The arylation of anilines, escpecially of unsubstituted ones with o-bromoanisoles requires stronger bases such as NaOt-Bu or KOt-Bu [34][35][36][37][38]. This is due to the deactivated, electron-rich

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• alkenes and alkylation/arylation using organic halides [29][30]. These previous studies have prompted us to expand the scope of cobalt catalysis for the C–H alkenylation and thus to develop an ortho C–H alkenylation reaction of pivalophenone N–H imine with alkenyl phosphates using a new cobalt–NHC

• , the NHC precursor featuring a cyclohexane backbone and 2,6-diethylphenyl groups (L1·HBr), which proved to be the optimal ligand for the C–H arylation of pivalophenone N–H imine as well as for the C–H alkenylation of N-arylimine (Scheme 1a, b) [28][29], was not particularly effective for the present

• reaction (Table 1, entry 8). To our delight, we observed a remarkable improvement in the reaction efficiency using the benzofused analogue of IPr·HCl (L2·HCl), affording 3aa in 88% yield without any trace of a dialkenylation product (Table 1, entry 9). It should be noted that, unlike the C–H arylation of

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

• Romain Sallio,
• Stéphane Lebrun,
• Frédéric Capet,
• Francine Agbossou-Niedercorn,
• Christophe Michon and
• Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

• -receptor agonists [8][9][10][11][12][13][14][15][16]. Indeed, the copper-catalyzed N-arylation of (3S)-26 was performed in dioxane with N,N-dimethylethylenediamine as ligand [27] to deliver the targeted pazinaclone analogue (3S)-27 in a fair yield (66%) without significant loss in enantiomeric purity

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• successfully developed a rhodium-catalyzed asymmetric arylation process leading to triarylmethanes 25. With the application of mild reaction conditions (40 °C, 15 h), a high enantioselectivity (≥90% ee) was reached with good to excellent yields. (Scheme 2). Starting from 2-naphthol, 2,2-disubstituted 3

Synthesis and stability of strongly acidic benzamide derivatives

• Frederik Diness,
• Niels J. Bjerrum and
• Mikael Begtrup

Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38

• of the corresponding imidoyl chlorides 10 with PCl5 in POCl3, followed by the additional reaction with trifluoromethanesulfonamide (1) and protonation by sulfuric acid (Scheme 1) [10]. In recent years, we have reported high yielding catalyst-free N-arylation by SNAr reaction of mono- or

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• ]. Later on, arylation, vinylation and alkynylation of glycine derivatives were also accomplished by the same group (Scheme 1) [13]. Using the Cu(OAc)2/pyrrolidine dual catalysts system, Huang developed the oxidative cross coupling of glycine derivatives with acetone in the presence of TBHP or DDQ as

Syn-selective silicon Mukaiyama-type aldol reactions of (pentafluoro-λ⁶-sulfanyl)acetic acid esters with aldehydes

• Anna-Lena Dreier,
• Andrej V. Matsnev,
• Joseph S. Thrasher and
• Günter Haufe

Beilstein J. Org. Chem. 2018, 14, 373–380, doi:10.3762/bjoc.14.25

• SF5X (X = Cl, Br, SF5) across π-bonds. The unconventional conditions usually required were overcome by Dolbier’s elegant triethylborane initiation [21]. Recently, the radical arylation of a SF5-substituted alkene was realized in order to gain access to SF5-containing dihydrobenzofurans and indolines

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

• 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

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

• 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

• diaryliodonium salts can generate benzynes under severe basic conditions, the resulted benzynes were allowed to undergo cycloaddition reaction with furan or N-arylation of secondary amides and amines. Due to the easy accessibility of the diaryliodonium salts, this kind of benzyne precursor is attracting

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

• , the O-arylation of 2-alkynoic acids, which are much more acidic than arenecarboxylic acids and alkanecarboxylic acids, and therefore, the conjugate bases of 2-alkynoic acids are much less nucleophilic than those of arenecarboxylic acids and alkanecarboxylic acids, was not studied. On the other hand

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

• aryl diazonium salts to give the corresponding diaryl sulfide in high yields. Very recently, Noël and co-workers applied the above-mentioned concepts for the selective arylation of cysteine and cysteine-containing peptides in batch as well as in a photomicroreactor (Scheme 18) [49]. They were able to

Reactivity of bromoselenophenes in palladium-catalyzed direct arylations

• Aymen Skhiri,
• Ridha Ben Salem,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2017, 13, 2862–2868, doi:10.3762/bjoc.13.278

• employed to prepare 2-heteroarylated selenophenes; whereas, 2,5-dibromoselenophene generally gave 2,5-di(heteroarylated) selenophenes in high yields using both thiazole and thiophene derivatives. Moreover, sequential catalytic C2 heteroarylation, bromination, catalytic C5 arylation reactions allowed the

• recent years, the Pd-catalyzed arylation, via a C–H bond activation, of a broad range of heteroaromatics using aryl halides as reaction partners was demonstrated to be particularly effective for the preparation of bi(hetero)aryls [22][23][24][25][26][27][28][29][30][31]. Among the reported results, a few

• examined. The expected product 7 was obtained in a high yield of 81%. Thus, for Pd-catalyzed direct heteroarylations of 2-bromoselenophene, only the heteroarenes containing C–H bonds with low Gibbs free energies of activation [41] should be employed. By contrast, the direct arylation reactions with 2,5

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• Determining the accurate chemical structures of synthesized compounds is essential for biomedical studies and computer-assisted drug design. The unequivocal determination of N-adamantylation or N-arylation site(s) in nitrogen-rich heterocycles, characterized by a low density of hydrogen atoms, using NMR

• product structure were also found for N-arylation or N-alkylation with tert-butyl fragments in the series of 1,2,3-triazole [15][16], tetrazole [17][18][19][20], and purine [21] derivatives. Meanwhile, knowledge of the accurate chemical structures of N-substituted heterocycles is essential for biomedical

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• Göttingen, Germany 10.3762/bjoc.13.187 Abstract A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular C-arylation of tertiary 1-(methoxycarbonyl)methanesulfonamides under palladium catalysis is described. In case of the α-toluenesulfonamide derivative, an unexpected

• formation of a 2,3-diarylindole was observed under the same conditions. Keywords: arylation; fused-ring systems; indole formation; palladium catalysis; sultams; Introduction The sulfonamide functional group stands out as one of the most important pharmacophores. At the same time, cyclic sulfonamides

• efficiently used for the preparation of ortho-functionalized anilines. This contribution deals with a new access to ring-annelated sultams by an intramolecular Pd(0)-catalyzed arylation of tertiary sulfonamides bearing an additional C–H acidic center (Scheme 1). From several potentially suitable electron

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• ][75][76]. In view of this, chemists have introduced alternative energy sources like, microwave, sonication, mechanomilling, etc. [12][27][77]. Su and co-workers reported a copper-catalyzed arylation of anilines using arylboronic acid under high speed ball-milling conditions. Using 1.0 equiv of Cu(OAc

• palladium-catalyzed site selective mechanochemical dehydrogenative C–H/C–H arylation between oxime and arene moiety for the construction of Csp2–Csp2 bond with high para-selectivity of arene component via LAG. Using 10 mol % of Pd(OAc)2, 2.0 equiv of Na2S2O8 and 1.0 equiv TfOH the biaryls were synthesized

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• first palladium-catalyzed arylation of thiols was reported by Migita and co-workers in 1980 [5], and soon after Cristau and co-workers developed a nickel-catalyzed route for C–S cross-coupling reactions [6]. Other metals such as copper [7], cobalt [8], iron [9], rhodium [10], manganese [11], indium [12

New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties

• Daria G. Selivanova,
• Alexei A. Gorbunov,
• Olga A. Mayorova,
• Alexander N. Vasyanin,
• Igor V. Lunegov,
• Elena V. Shklyaeva and
• Georgii G. Abashev

Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158

• ], Ullmann coupling [13][14], Buchwald–Hartwig amination [15] or N-alkylation of carbazole in the presence of alkali metal carbonates under MW irradiation [16]. In our case, the N-arylation was realized under phase transfer conditions using triethylbenzylammonium chloride (TEBA) as a catalyst [17][18

A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines

• Benedikt C. Melzer and
• Franz Bracher

Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156

• starting from an isoquinoline bearing an ester group at C-8. In a photoredox-catalyzed direct C–H arylation a 4-methoxyphenyl residue from a methoxyphenyldiazonium salt was introduced at C-1, and after ester hydrolysis intramolecular Friedel–Crafts acylation afforded menisporphine (2). In continuation of