A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• of biaryl products with triazole. For this, 4-bromoaryl derivatives were initially treated with phenylboronic acid. The biaryl derivatives were then reacted with phenylacetylene to give triazole-containing biaryl compounds in high yields. Stilbenes were also applied in the reaction under similar

Efficient synthesis of 3,6,13,16-tetrasubstituted-tetrabenzo[a,d,j,m]coronenes by selective C–H/C–O arylations of anthraquinone derivatives

• Seiya Terai,
• Yuki Sato,
• Takuya Kochi and
• Fumitoshi Kakiuchi

Beilstein J. Org. Chem. 2020, 16, 544–550, doi:10.3762/bjoc.16.51

• groups to form biaryl frameworks. Traditionally, transition-metal-catalyzed cross-coupling reactions of aryl halides or pseudohalides with arylmetal reagents have been employed for the connection of two aryl units [5][6][7][8][9]. However, in search of more efficient synthetic routes, C–H arylation

Copper-catalyzed remote C–H arylation of polycyclic aromatic hydrocarbons (PAHs)

• Anping Luo,
• Min Zhang,
• Zhangyi Fu,
• Jingbo Lan,
• Di Wu and
• Jingsong You

Beilstein J. Org. Chem. 2020, 16, 530–536, doi:10.3762/bjoc.16.49

• a challenging task due to the inaccessibility of the corresponding 7-halonaphthalene substrates [12]. Recently, transition metal-catalyzed C–H bond functionalization has emerged as a powerful tool to construct various biaryl skeletons [13][14][15][16][17]. The direct C7−H arylation of 1-naphthoic

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• 9,9-dihydro-5-silafluorene (2f), which gave the spiro-type phenoxasilin 3f in 96% yield. We then investigated the scope of the starting biaryl ethers used in the reaction as well as related derivatives thereof using dihydrodiphenylsilane (2a, Scheme 3). Pyrrolidine-substituted diaryl ether 1b was

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• (NHCs) have proved to be versatile ligands in organometallic chemistry [82]. The synthesis of sterically crowded biaryl ligands is still a challenging task, especially under mild reaction conditions. The diphosphine complexes of imidazolylphosphines proved to be an alternative towards the coupling of

• sterically crowded biaryl ligands as they showed outstanding performances [8]. Phosphines with imidazole and imidazoline functional groups present some interesting features. The imidazolium functionality mimics active sites in biological molecules [83][84]. The ionic nature adds another dimension to the

Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

• Ryo Takishima,
• Yuji Nishii,
• Tomoaki Hinoue,
• Yoshitane Imai and
• Masahiro Miura

Beilstein J. Org. Chem. 2020, 16, 325–336, doi:10.3762/bjoc.16.32

• . The crystal of 4b is classified into a space group P4322 (tetragonal) with a biaryl torsion angle of 74.4° (Figure 4b). A considerable intermolecular π–π stacking interaction was observed in between its polyaromatic fragments whose distance is approximately 3.44 Å. The polycyclic subunits overlap each

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• formation of carbazoles from biaryl derivatives. Mechanism for the synthesis of phenol derivatives with photoredox catalyst 8. Possible mechanism for the generation of phenols with the aid of photoredox catalyst 5. Proposed mechanism for the synthesis of monobrominated compounds. Mechanism for the synthesis

• olefination. C–H olefination of phenolic ethers. Decarboxylative acylation of acetanilides. Synthesis of fluorenone derivatives by intramolecular deoxygenative acylation of biaryl carboxylic acids. Synthesis of benzothiazoles via aerobic C–H thiolation. Synthesis of benzothiazoles via oxidant-free C–H

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• colchicine per se, aiming at compounds where one isomer would be almost biologically inactive such that light can be used to effect a photoisomerisation-based switch-on/switch-off of bioactivity. The end-to-end distance of the HTI scaffold is significantly longer than that in either the biaryl colchicine or

• different substituent patterns to those of colchicine, and attempted to rationally determine these. Firstly, since the HTI scaffold is longer than a biaryl motif but should occupy a similar volume in the pocket, we assumed that we would have to reduce the substituent bulk present on colchicine

• scaffold could best be reduced in volume by "shortening" this substituent, maintaining the abovementioned non-polar interaction. Secondly, since the torsion angle of the HTI is far lower than that of (Z)-stilbenes or biaryl compounds, we considered that even with shortening, their SARs might not directly

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• . The addition of 1-bromo-4-methoxynaphthalene (1, 0.9 equiv) and K3PO4, and stirring overnight at 110 ºC, afforded the biaryl methyl ether 5 in an 82% yield (Scheme 1). Similarly, Buchwald´s methodology [41] was applied in the synthesis of 7, which was obtained in 70% yield after tetrahydropyran (THP

• ) group deprotection in MeOH/CH2Cl2 using TsOH·H2O as the catalyst (Scheme 2). In a conventional triflation (Tf2O, DMAP cat.), 7 was converted into 8 with a yield of 86%. For the synthesis the triflates 9–11 a one-pot demethylation–triflation sequence was followed (Scheme 2). The treatment of biaryl

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• latter one. One of the main reasons is that an azobenzene has a relatively simple structure that can resemble various biaryl moieties of bioactive compounds: two aromatic rings linked with a bridge (e.g., amide, ether, alkane or alkyne) [8]. In the case of azobenzene the bridge is a diazene group (also

• called azo group) and depending on the wavelength of illumination, a linear trans-isomer or a bent cis-isomer can be obtained [9]. If certain biaryl moieties are replaced by an azobenzene (i.e., azologization approach), there is a relatively good chance that one of the resulting photoisomers will have a

• spatial disposition similar to the original biaryl unit and, therefore, a similar biological activity that might change upon isomerization of the azobenzene [8]. The second reason for the success of azobenzene in the photopharmacology field is the robust photoisomerization. It provides typically high

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

• Benedikt C. Melzer,
• Alois Plodek and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

• 4,5-disubstituted benzo[c][2,7]naphthyridines utilizing ortho-directed ring metalation/biaryl cross-coupling strategies [9]. 4-Chlorobenzo[c][2,7]naphthyridine (9a) was conveniently converted into other 4-substituted benzo[c][2,7]naphthyridines by substitution reactions with nucleophiles (alcoholates

• manner of a radical reaction [27][28][29]. Starting with alcohol 12b, a putative precursor of the alkaloid kuanoniamine A (3), the three described cyclization methodologies were tested starting directly from alcohol 12b as well as from ketone 21, obtained by oxidation of 12b. The intramolecular biaryl

• -catalysed intramolecular tandem stannylation/biaryl coupling protocol gave the attempted pentacyclic products [32]. However, having the biaryls 20a and 20b prepared we intended to develop a new approach to pyrido[4,3,2-mn]acridines by an alternative intramolecular cyclization step. To reach that aim, the

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• trifluoromethylation of vinyl triflates and nonaflates (Scheme 65). A variety of trifluoromethylated cyclohexenes were obtained using a catalyst system, which was composed of Pd(dba)2 or [(allyl)PdCl]2 and the monodentate biaryl phosphine ligand t-BuXPhos. Also, TMSCF3 and KF were more suitable to the

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• with a biaryl ether diisocyanide and two equivalents of paraformaldehyde and a monoprotected diamine. After the initial macrocyclization, steroidal macrocycle 71 was deprotected by removal of the Cbz groups and subsequently submitted to a second multicomponent macrocyclization protocol – in this case

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• to be used directly to obtain macrocycles of this complexity and size. The synthesis of macrocycles with up to 16 new bonds being formed simultaneously has been described (Scheme 22). The strategy was based on combining steroidal dicarboxylic acids 115 and biaryl ether diisocyanide 116 [38]. The

• approach provided the synthesis of steroid-biaryl ether hybrid macrocycles 117 and 118 with up to 68 members by the MiBs strategy. Another representative example of MiBs is the synthesis of the biaryl ether-containing macrocycles 123a–f (Scheme 23) [39]. The synthetic strategy involved the mixing of three

• products containing biaryl ether-cyclopeptoid macrocycles 127 and 128 (Scheme 24) [40]. The approach used involved diisocyanides 124 (representing a biaryl ether moiety) reacting with aliphatic diacid/diamine and amine/aldehyde, respectively, to generate the target macroheterocycles. Wessjohann and Rivera

A diastereoselective approach to axially chiral biaryls via electrochemically enabled cyclization cascade

• Hong Yan,
• Zhong-Yi Mao,
• Zhong-Wei Hou,
• Jinshuai Song and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2019, 15, 795–800, doi:10.3762/bjoc.15.76

• the biaryls with good to excellent central-to-axial chirality transfer. Keywords: axial chirality; biaryl; electrochemistry; oxidation; radical; Introduction Axially chiral biaryls are prevalent in natural products, bioactive molecules and organocatalysts [1][2]. Among the many methods that have

• imidazopyridine-based biaryl 3a in 68% yield with good diastereoselectivity (14:1 dr). Replacing the t-Bu group at the propargylic position with iPr (Table 1, entry 2) or on the phenyl ring with Ph (Table 1, entry 3) or OiPr (Table 1, entry 4) all resulted in low diastereoselectivity (2:1 to 3:1). The scope of

• Me (3j). Pyridyl rings bearing multiple substituents were also tolerated (3k and 3l). The stereochemistry of the biaryl product was determined by obtaining an X-ray crystal structure of 3k. The t-Bu-substituted phenyl ring on the alkyne moiety containing an extra OMe (3m) or Me (3n and 3o) group was

Solid-phase synthesis of biaryl bicyclic peptides containing a 3-aryltyrosine or a 4-arylphenylalanine moiety

• Iteng Ng-Choi,
• Àngel Oliveras,
• Lidia Feliu and
• Marta Planas

Beilstein J. Org. Chem. 2019, 15, 761–768, doi:10.3762/bjoc.15.72

• Iteng Ng-Choi Angel Oliveras Lidia Feliu Marta Planas LIPPSO, Departament de Química, University of Girona, Maria Aurèlia Capmany 69, Girona 17003, Spain 10.3762/bjoc.15.72 Abstract A methodology for the solid-phase synthesis of biaryl bicyclic peptides containing a Phe-Phe, a Phe-Tyr or a Tyr

• resulting biaryl monocyclic peptidyl resin leading to the formation of the expected biaryl bicyclic peptide. This study provides the first solid-phase synthesis of this type of bicyclic compounds being amenable to prepare a diversity of synthetic or natural biaryl bicyclic peptides. Keywords: borylation

• amino acids [11]. Cyclic peptides containing biaryl linkages constitute attractive targets. On the one hand, a wide range of biaryl natural products have been reported to display interesting biological properties, such as biphenomycins, arylomycins and glycopeptide antibiotics [4]. On the other hand

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• ). For 8ax the OH group is parallel situated to the biaryl axis. For 8eq the OH group is orthogonal oriented to the biaryl axis. The fenchyl groups are abbreviated with (*) for more clarity. Computed hydrolyses of BIFOXSiCl2 (7) to BIFOXSiCl(OH) 8ax and BIFOXSiCl(OH) 8eq and subsequent computed

A simple and effective preparation of quercetin pentamethyl ether from quercetin

• Jin Tatsuzaki,
• Tomohiko Ohwada,
• Yuko Otani,
• Reiko Inagi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2018, 14, 3112–3121, doi:10.3762/bjoc.14.291

• position shows the lowest reactivity, while the OH group at 7 position shows the highest reactivity. In the cases of anions 2B, all the corresponding anions 3'-anion 2B, 4'-anion 2B, 5-anion 2B, 7-anion 2B tended to take planar overall structures, that is, the biaryl dihedral angles (3–2–1'–2') were

• reduced from that of the neural species (2B: −43.8°). In particular, 4'-anion 2B and 5-anion 2B are affected by conjugation between the chromenone moiety and the phenyl group (biaryl dihedral angle: −29.6° in 4'-anion 2B; −29.6° in 5-anion 2B). Change of proton affinity during the methylation reaction

• '-tetramethylquercetin (4, conformation 4A). Conformation 4A has a structure in which the phenyl group is rotated due to the OMe group at the 3 position (the biaryl dihedral angle is +28.2°), and upon ionization of the OH at 5 position to the oxyanion, the planarity was not significantly restored. This may increase the

Pathoblockers or antivirulence drugs as a new option for the treatment of bacterial infections

• Matthew B. Calvert,
• Varsha R. Jumde and
• Alexander Titz

Beilstein J. Org. Chem. 2018, 14, 2607–2617, doi:10.3762/bjoc.14.239

• signal molecules and mimic their structures. The PQS system of P. aeruginosa is particularly attractive and can be considered as a pathogen specific target. The biosynthesis of the PQS signal 23 involves a set of biosynthetic enzymes PqsABCDEH and its autocatalytic receptor PqsR (MvfR). Biaryl methanols

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• a CM in an efficient manner. Biaryl derivatives In view of the interesting properties of biaryl derivatives, we have identified a three-step sequence, which involve cross-enyne metathesis (CEM), DA reaction followed by SM coupling [46]. To this end, acetylene derivatives 96a,b were subjected to CEM

• DDQ to give biaryl products 99a,b. Further, aryl halides 99a,b were subjected to SM coupling by employing various boronic acids (e.g., 4-formylphenylboronic acid (100) to produce biaryl derivative 101 (80% from 99a and 74% from 99b). Very recently, Suresh Babu and co-workers [47] demonstrated a new

• coupling approach to Z-stilbene derivative 85. Synthesis of substituted trans-stilbene derivatives via SM coupling and RCM. Synthesis of biaryl derivatives via sequential EM, DA followed by SM coupling. Synthesis of the dibenzocyclooctadiene core of schisandrene. Synthesis of cyclophane 115 via SM coupling

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• , Tanaka presented an atropselective synthesis of axially chiral all-benzenoid biaryls by gold-catalysed intramolecular hydroarylation of alkynones to give the desired atropisomeric product with a good ee value of 70% [26]. Conventional approaches to the synthesis of biaryl compounds having axial chirality

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• ]quinolizinium derivatives have to be optimized [34][35]. Accordingly, we extended our studies to improve the conditions of the Suzuki–Miyaura coupling towards biaryl-type benzo[b]quinolizinium derivatives 1a–d (Figure 1), namely to apply the alternative base-free Suzuki–Miyaura coupling reaction [39][40][41][42

• shift in CHCl3. This effect is presumably caused by a charge shift (CS) or, more likely, by a charge transfer (CT) in the excited state from the electron-donating aryl unit to the excited quinolizinium (Scheme 3) [57], which has been proposed also to take place in structurally resembling excited biaryl

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• equiv) led to the formation of the biaryl 23a in 92% yield (Table 2, entry 1). The colour of the reaction mixture remained yellow. The use of solvents other than water gave inferior yields (Table 2, entries 2 and 3) which could be attributed to the high hydrophilicity of the pincer complex 17a. Several

• bases including pyridine, Et3N, KOH, K2CO3 and Cs2CO3 were then evaluated. All except Et3N provided the expected biaryl 23a in comparable and excellent yields (Table 2, entries 4–8). The poor performance of Et3N as base in the reaction could be due to its low water solubility. KOH as a common laboratory

• activity of 20a was investigated in the Suzuki–Miyaura coupling reaction of 4-bromoanisole (21a) and phenylboronic acid (22a) as a proof of concept. As expected, it catalysed the reaction and provided biaryl 23a in moderate yield demonstrating the potential of such complexes in coupling reactions (Scheme 4

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

• purpose various chiral iodine reagents were synthesized having an axially chiral biaryl backbone. In this part, we mainly focused on the transformations using chiral iodine reagents instead of achiral iodine reagents in a combination with other chiral sources [61]. More than one century after Pribam

• for the alkynylation of β-ketoesters [76]. Pouységu and Quideau et al. prepared new axially chiral biaryl I(III) reagents 18 assembled with alkynyl ligands. They were able to achieve alkynylation of β-ketoesters 114 as well as dearomative alkynylation of phenolic derivatives 118 to obtain derivatives

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• ) [31][32][33][34][35]. A preliminary scheme of the planned synthetic route is shown in Figure 1. As can be seen, the key step of our processes is the formation of the biaryl unit via a Suzuki–Miyaura cross-coupling reaction. To provide solid Pd catalysts with a high potential for the planned approaches