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

• non-symmetrical diaryl-λ3-iodanes raises the issue of regioselectivity. This strategy has been then extended to the preparation of alkyne-substituted alkylidenefluorenes 53 by replacing the arylboronic acid with a second equivalent of the terminal alkyne and performing the reaction at 35 °C (Scheme 18

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

• of the desired aryl moiety, and the ortho-effect exerted by the 2-amido substituent was expected to improve the chemoselectivity further. Salt 5a was synthesized in good yield using our reported arylboronic acid methodology [33] (Scheme 3). Attempts to form the corresponding tosylate salt, either

• straightforward using 2-iodophenylboronic acid (Scheme 4a). The use of an anisyl dummy proved more difficult, and tetrafluoroborate 7b was isolated with impurities using the arylboronic acid methodology [33] (Scheme 4b). The mCPBA/TsOH methodology [34] with 1,2-diiodobenzene (10) and anisole or trimethoxybenzene

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• presence of various substituents (R1) at different positions of the aryl moiety of isatin imines, giving comparable enantioselectivities (91–94% ee). Moreover, the arylboronic acid scope was also found wide and various para- as well as meta-substituted arylboronic acids reacted smoothly, giving the

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• ]. Arylboronic esters have recently been probed by Toshima and co-workers as a successful linkage for the IAD method [109]. The arylboronic sugar derivatives, such as 79, can be easily obtained from the corresponding 4,6-diol 78 and a arylboronic acid in toluene at reflux (Scheme 19). Boronic ester 79 was then

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

• )2 and 2.5 equiv of K2CO3 and in the presence of milling auxiliary silica gel, differently substituted arylboronic acid and anilines led to N-arylated products in 58–86% yield (Scheme 15) [78]. They have also explored the reactivity of other amines like alkyl, primary, secondary, heterocyclic, etc

Development of a method for the synthesis of 2,4,5-trisubstituted oxazoles composed of carboxylic acid, amino acid, and boronic acid

• Kohei Yamada,
• Naoto Kamimura and
• Munetaka Kunishima

Beilstein J. Org. Chem. 2017, 13, 1478–1485, doi:10.3762/bjoc.13.146

• reaction conditions). A number of trisubstituted oxazoles were synthesized using 5-(triazinyloxy)oxazoles 3 and various boronic acids 4 (Table 3). To our disappointment, the reaction of 3aa with the arylboronic acid possessing an electron-withdrawing group 4b decreased the yield of 5aab (25%, Table 3

• conditions A. The arylboronic acid with an electron-donating group 4c also provided a better yield under conditions B rather than conditions A (Table 3, entries 3 and 4). The desired naphthyloxazole 5aad was obtained in a high yield (77%, Table 3, entry 5). Introduction of a p-tolyl group afforded a good

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• before the formation of copper complex. In 2016, the Wang and Shi group reported a CuI-catalyzed C–H hydroxylation of thiophenols, in which disulfide directed the hydroxylation [58]. Using aryl thiol and arylboronic acid as starting materials, C–H hydroxylation and C–S coupling sequentially occurred in

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• 55 via a formal 1,4-addition of arylboronic acids to β-aryl-α,β-unsaturated ketones and esters [39]. Thus, the α,β-unsaturated diester 52 was coupled with arylboronic acid in the presence of rhodium(I)/Chiraphos® complex as a catalyst to obtain derivative 53, which next underwent a Claisen

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• , Table 1, entry 2). Other copper salts such as Cu(OTf)2 and Cu(OAc)2 were much less effective (Table 1, entries 3 and 4). A significant increase of yield was observed when the stoichiometry of the system was changed to a slight excess of arylboronic acid. When more than 1.6 equivalents of 2 were involved

• stereofacial nucleophilic addition of the arylboronic acid to produce the desired enantioenriched arylated product VII. The Ir(III) is regenerated in the presence of the sacrificial external oxidant TBHP. Conclusion In conclusion, we have successfully developed a highly efficient light-mediated coupling method

• purified by column chromatography or preparative thin-layer chromatography on silica gel to yield the corresponding arylated compound 3. Dibromomethane was used as internal standard for 1H NMR analysis. Reaction scope. Reaction conditions: THIQs (0.10 mmol), arylboronic acid (0.30 mmol), TBHP (0.2 mmol

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

• Carl J. Mallia,
• Paul M. Burton,
• Alexander M. R. Smith,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1598–1607, doi:10.3762/bjoc.12.156

• . The yield then stabilised from 135 min at 96% indicating steady state was achieved. As it had been determined that the amount of arylboronic acid excess could not be lowered (entries 12 and 13, Table 1), the use of a polymer supported scavenger was tested in an effort to sequester the excess boronic

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

• palladacycle; (2) reaction of the cationic palladacycle with an aryl iodide, arylboronic acid or acrylate, and (3) regeneration of the active cationic palladium catalyst. The reaction between a cationic palladium(II) complex and arylurea allowed the formation and isolation of the corresponding palladacycle

• and arylboronic acid to afford the biaryl in high yield (Scheme 4). Representative results for the reactions between aryl iodides and arylboronic acids are summarized in Figure 2. These arylations tolerate various combinations of substrates and reagents having electron-withdrawing or electron-donating

• ], those catalyzed by cationic palladium have been much less thoroughly examined. We hypothesized that our catalytic cycles for the Fujiwara–Moritani, arylboronic acid, and aryl iodide coupling reactions catalyzed by cationic palladium complexes are composed of three key steps; (1) aromatic C–H activation

A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

• Dariusz Błachut,
• Joanna Szawkało and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2016, 12, 835–845, doi:10.3762/bjoc.12.82

• -trimethylpyridine in low yield (approx. 5%, not isolated), mainly because of the additional side-reactions that took place between 3-(2-chlorophenyl)-5-bromo-2,4,6-trimethylpyridine/diarylpyridine and 2-chlorophenylboronic acids at the Cphenyl-Cl position, as was confirmed by GC–MS. The arylboronic acid with a

• ), reaction conditions (the nature of the palladium/ligand, temperature, base, solvents) and the steric interactions between both cross-coupling partners. Minard et al. [59] pointed out that if an arylboronic acid involved in sequential couplings bears substituents with electron-withdrawing and electron

• , we applied route 1 as the way to obtain the desired diarylpyridines P7 (46–66). Several examples of monoarylation of symmetrical dihaloarenes have been published so far. A low molar ratio of dihaloarene/arylboronic acid often promoted a single coupling [56][74][75][76][77][78]. When the substrate

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• arylboronic acid is synthetically useful because it can be readily deprotected with a dilute aqueous acid [20]. We envisioned that diisopropylaminoborane (1g) [21] could be a useful boron source because the resulting aminoborylated products are sufficiently labile to be converted into various boron

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• with simultaneous C–O bond cleavage subsequently occurs in 16 to give the triarylmethane 11 and copper(OH)(OTf) (17). The reaction of 17 with arylboronic acid 10 regenerates 15 and results in the formation of stable boric acid. The driving force for the triarylmethane formation is the generation of a

• carbon can be assembled in a two-step protocol, is modular in nature. The first step is the synthesis of diarylmethanol and the second step is the replacement of the hydroxy group in the resulting diarylmethanol by a third aryl group by employing arylboronic acid under copper catalysis. As a proof of

• of diarylmethanol and the other of the arylboronic acid. We designed the protection of the C(4) hydroxy group in the arylboronic aicd with the photolabile 2-nitrobenzyl (NB) group, so that it can be removed without affecting the rest of the molecule. The synthesis of triarylmethane 22 began with the

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• (Scheme 12). The copper-mediated oxidative trifluoromethylation of arylboronic acids are important reactions in organic chemistry because arylboronic acids are widely used. Oxidative, aromatic perfluoroalkylation reactions with arylboronic acid derivatives have been studied by several groups. Qing et al

Assembly of synthetic Aβ miniamyloids on polyol templates

• Sebastian Nils Fischer and
• Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

• only low tendencies of boronic ester formation [23]. Therefore, we turned to cis-dihydroxylated 5, which exhibited a unique reactivity towards boronic acids because it forms two anellated cis-fused rings. 5 shows 86% esterification after drying in a 1:1 mixture with the arylboronic acid 6, a single

Half-sandwich nickel(II) complexes bearing 1,3-di(cycloalkyl)imidazol-2-ylidene ligands

• Johnathon Yau,
• Kaarel E. Hunt,
• Laura McDougall,
• Alan R. Kennedy and
• David J. Nelson

Beilstein J. Org. Chem. 2015, 11, 2171–2178, doi:10.3762/bjoc.11.235

• ketone α-arylation [3][13]. These species can also catalyse hydrosilylation reactions [14]. Chatani and co-workers have recently reported that ICy (ICy = 1,3-dicyclohexylimidazol-2-ylidene) is a superior ligand for the cross-coupling of aryl and benzyl methyl ethers with arylboronic acid esters, when

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• and an RCM as key steps. In this regard, the α,α'-dibromo-m-xylene (136) was treated with arylboronic acid 180, to give the dialdehyde 181 which on reaction with indium-mediated Grignard addition reaction gave diolefin 182. Later RCM of diolefin 182 delivered cyclophane 183. Subsequent oxidation of

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• ]. The palladium-catalyzed cross-coupling of arylboronic acid and aryl halides in the Suzuki–Miyaura (SM) reaction is one of the most popular and important methods to obtain biaryls, which are essential structures of many important compounds such as natural products [7], agrochemicals [8

• scope of the SM cross-coupling reaction using the 4-AAP–Pd(II) complex, we examined the reactions of a wide array of electronically diverse aryl iodides and bromides with electron-withdrawing or electron-donating substituents on the phenylboronic acids. The effects of the substituents of the arylboronic

• acid on the product yield of this reaction have been analyzed. Of particular note is our observation that many products could be isolated without the need for column chromatography. Using this protocol, all 8 tested reactions of phenylboronic acids 1a–1d with phenyl iodides 2a, 2b proceeded smoothly to

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• presence of arylboronic acid (iv and v). The latter evidence prompted the authors to conclude that the aryl group was transferred from the boronic acid and not from the gold complex (i.e. the phenyl group on the in situ formed PPh3AuPh complex acts as a spectator in the process). Based on such observations

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• mechanism remains to be elucidated, the authors presume that the reaction proceeds via generation of CuCF3 followed by transmetallation with the arylboronic acid. The diamine stabilizes the CuCF3 species. This facilitates the oxidation to Cu(II) or Cu(III) species which undergo facile reductive elimination

• Cu(I) to Cu(II) under photoexcitation. Both products then combine to afford a Cu(III)CF3 species, which undergoes transmetallation with the arylboronic acid. Finally, reductive elimination from Cu(III)(aryl)(CF3) affords the desired aryl-CF3 product (Figure 11 and Table 26). M. Beller et al

• . investigated the copper-catalyzed trifluoromethylation of aryl and vinyl boronic acids with in situ generated CF3-radicals using NaSO2CF3 (Table 27 and Table 28) [97]. The CF3 radical is generated from the reaction of TBHP (t-BuOOH) with NaSO2CF3. Transmetallation of the arylboronic acid with the Cu(II

Consecutive cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate with boronic acids: efficient synthesis of 1,1-diaryl-2,2-difluoroethenes

• Ju Hee Kim,
• Su Jeong Choi and
• In Howa Jeong

Beilstein J. Org. Chem. 2013, 9, 2470–2475, doi:10.3762/bjoc.9.286

• of 2 with arylboronic acids prompted us to examine similar coupling reactions with alkenylboronic acids. The same reaction conditions of the mono-coupling reaction of 2 with arylboronic acid was applied to the alkenylation of 2. Therefore, the cross-coupling reaction of 2 with trans-2

Acid, silver, and solvent-free gold-catalyzed hydrophenoxylation of internal alkynes

• Marcia E. Richard,
• Daniel V. Fraccica,
• Kevin J. Garcia,
• Erica J. Miller,
• Rosa M. Ciccarelli,
• Erin C. Holahan,
• Victoria L. Resh,
• Aakash Shah,
• Peter M. Findeis and
• Robert A. Stockland Jr.

Beilstein J. Org. Chem. 2013, 9, 2002–2008, doi:10.3762/bjoc.9.235

• carried out in an oil bath. HRMS data were obtained on a Thermo Scientific Exactive Plus LC–MS system (ESI). General method for the arylation reactions: general procedure A: For a typical reaction, (NHC)AuCl, 2 equiv of the arylboronic acid, 2 equiv of Cs2CO3, and a magnetic stirring bar were added to a

• . aChlorogold precursor (0.32–0.37 mmol), 2 equiv arylboronic acid, 2 equiv Cs2CO3, 50 °C, 20 min, iPrOH (1.5 mL), microwave irradiation. bIsolated yields. cTHF was used as the solvent. Hydrophenoxylation of alkynesa,b. aAlkyne (0.28 mmol), phenol (0.56 mmol), 130 °C, 20 min, no solvent. bIsolated yields

Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes

• Yan-Chao Shi,
• Rong-Fei Yang,
• De-Wei Gao and
• Shu-Li You

Beilstein J. Org. Chem. 2013, 9, 1891–1896, doi:10.3762/bjoc.9.222

• ][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Inspired by their works, we reported a direct arylation of ferrrocene with arylboronic acid to introduce planar chirality into the ferrocene backbone using N,N-dimethylaminomethyl as the directing group and Boc-L-Val-OH as the ligand

Palladium(II)-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

• Tanveer Mahamadali Shaikh and
• Fung-E Hong

Beilstein J. Org. Chem. 2013, 9, 1578–1588, doi:10.3762/bjoc.9.180

• of LiBr (30 mol %, Table 3, entry 13). On the other hand, the employment of CuBr (30 mol %) with the presence of Pd(OAc)2 resulted in a 42% yield of trans-stilbene (3a) (Table 3, entry 14). Thus, the optimized reaction conditions for the Heck reaction here is the use of arylboronic acid (1 mmol