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

• ) and [NiCl(Cp)(IPr*OMe)] (7) due to their demonstrated competence as catalysts for the arylation of anilines [11]. The results from the cross-coupling reactions with 4’-bromo- and 4’-chloroacetophenone are summarised in Table 3; running the latter reaction for more than 2 h did not lead to significant

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• equiv of CuI and PivOH, the EWG-functionalized o-arylphenols 37 underwent simultaneous C–H iodination and intramolecular C–H o-arylation by heating in DMSO at 140 °C, which led to the production of iodinated dibenzo[b,d]furans in either the form of 38 or 39 depending on the position of the EWG. The CuI

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• . Palladium-catalyzed desulfitative arylation of heteroarenes allowed in a first step the synthesis of fluoroaryl-heteroarene units in high yields. Then, the next steps involve direct arylation with aryl bromides catalyzed by PdCl(C3H5)(dppb) to afford triad or tetrad heteroaromatic compounds via

• )stannane and 1,4-difluoro-2,5-diiodobenzene (Figure 1a) [3]. However, this methodology required the pre-synthesis of the stannane derivative, which is not eco-friendly. More recently, the direct C–H bond arylation has appeared as one of the most sustainable protocols for the synthesis of poly(hetero)arenes

• in high yields in only a few steps with the respect of the environment [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Since the reports on transition metal-catalyzed direct arylation of polyfluorobenzenes by Fagnou (Figure 1b) [26], and others [27][28][29][30][31][32][33

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• × 10−9 and 9 × 10−9 mol/cm2, respectively. A recent example of the chemical preparation of PT with pendant TTF-units has been reported [53] (Scheme 4) where direct arylation polymerisation of quaterthiophene 13a and 3-(acetoxymethyl)thiophene (13b), followed by acidic hydrolysis of the ester groups in

• prepared by electropolymerisation and post-modification of polymerised PT through iodoalkyl functionality. Synthesis of PT with pendant TTF by post-modification of the polymer prepared by direct arylation. Retrosynthetic scheme for the synthesis of the monomer building block which is required for the

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• for an efficient reaction. Alkali metal acetates are known to facilitate decomposition of aryldiazonium salts by the formation of diazoacetates and diazo anhydrides, which decompose to aryl radicals [76]. These additives were used in Meerwein arylation of isopropenyl acetate [77]. In our case, two

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• obtained together with recovered starting material. In order to test the functionalization of the above synthesized aryl iodides through a subsequent transition-metal-catalyzed coupling reaction we subjected three of them to a copper-catalyzed N-arylation reaction. Thus, the iodides 3b, 3d and 4d were

• in A2058 melanoma cells (Figure 6). The best result was obtained with 1f at 10−5 M, which induced 31.9 ± 0.1% growth inhibition in cells treated for 72 h. The linear N-arylated pyrroles 1b and 1e were poorly active. Arylation by a thiophene moiety (1a and 2a) moderately increased the

• compounds 3d and 4d. Procedure 7 for the N-arylation of imidazole [47]. A mixture of the prepared iodide (1.0 mmol), Cu2O (0.10 g, 0.10 mmol), Cs2CO3 (0.65 g, 2.0 mmol), imidazole (0.14 g, 2.0 mmol) and DMSO (0.5 mL) was stirred for 24 h at 110 °C under argon. After cooling to room temperature, the mixture

Pd(OAc)₂-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

• Biplab Mondal,
• Somjit Hazra,
• Tarun K. Panda and
• Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

• . However, sometimes the issue of regioselectivity can be resolved by the electronic property of the substrate itself. Pioneering work published by Fagnou et al. shows how a catalyst inverts its selectivity and reactivity between the coupling partners to achieve indole C3-arylation in a cross coupling

Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors

• Iris Binyamin,
• Shoval Meidan-Shani and
• Nissan Ashkenazi

Beilstein J. Org. Chem. 2015, 11, 1332–1339, doi:10.3762/bjoc.11.143

• group in 5, which may be susceptible to a second alkylation/arylation. The 31P NMR chemical shifts of 5a–d appear at the characteristic ~+40 ppm region. The respective signal for 5e, which possess a second aryl substituent, appears in a higher field of δ +32 ppm, as expected. Most indicative and

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

• %, Scheme 12). In another occasion, Rajakumar and co-workers [102] have synthesized a series of stilbenophanes (e.g., 81) involving N-arylated carbazole moieties possessing small and large cavities. The precursor 80 required for the McMurry reaction was synthesized by the N-arylation of carbazole with the

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• flow reactor simplifies the practical aspects of the transformation, however, extra precautions were required in order to address and remove any leftover methylamine that would pose a significant hazard during scaling up. The final arylation of 50 was intended to be performed as a SNAr reaction

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• to the N-arylation of MPTTFs and BPTTFs using a variety of aryl halides. Keywords: heterocycles; protecting groups; sulfur chemistry; tetrathiafulvalene; Ullman coupling; Introduction Tetrathiafulvalene (TTF) derivatives are of considerable interest in the fields of supramolecular chemistry and

• -cyanoethyl-protected thiols as a means to further functionalise MPTTFs with thioethers and (ii) copper-mediated N-arylation of both MPTTFs and BPTTFs. Results and Discussion An improved large-scale synthesis of N-tosyl-(1,3)-dithiolo[4,5-c]pyrrole-2-one (6) The known compound 6 [4][25] is an important

• convenient than the use of CsOH·H2O. N-Arylation of MPTTFs and BPTTFs N-Alkylation of MPTTFs and BPTTFs can be easily achieved using SN2 reactions between a deprotonated pyrrole and a suitably activated aliphatic species [19][28]. N-Arylation of MPTTFs and BPTTFs, which allows an annelated TTF to be

Chiroptical properties of 1,3-diphenylallene-anchored tetrathiafulvalene and its polymer synthesis

• Masashi Hasegawa,
• Junta Endo,
• Seiya Iwata,
• Toshiaki Shimasaki and
• Yasuhiro Mazaki

Beilstein J. Org. Chem. 2015, 11, 972–979, doi:10.3762/bjoc.11.109

• various types of aryl groups. At this point, we have chosen the direct arylation of TTF in the presence of a palladium catalyst as a key reaction for the chiral polymer synthesis (Scheme 2) [22]. Thus, the chiral allenes, (R)-9 or (S)-9, react with an active palladium species, prepared in situ from Pd(OAc

Tuning the size of a redox-active tetrathiafulvalene-based self-assembled ring

• Sébastien Bivaud,
• Sébastien Goeb,
• Vincent Croué,
• Magali Allain,
• Flavia Pop and
• Marc Sallé

Beilstein J. Org. Chem. 2015, 11, 966–971, doi:10.3762/bjoc.11.108

• modulating the bulkiness of the ancillary group on the metal complex precursor. The tetrapyridyl-exTTF ligand L1 (Scheme 1, Figure 1a) was synthesized through a palladium catalysed C–H arylation from the naked exTTF [39]. We already reported that the self-assembly process of this tetratopic ligand with cis-M

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• direct conjugation with the tetrathiafulvalene chromophore. The crystal packing of the arylated monopyrrolotetrathiafulvalenes is primarily defined by networks of C–H···X weak hydrogen bonds and short S···S contacts involving the tetrathiafulvalene moieties. Keywords: cyclic voltammetry; N-arylation

• in hot triethyl or trimethyl phosphite. Using the second approach [17][18][19], the aryl group is attached to the MPTTF moiety using a direct copper-mediated Ullmann-type N-arylation reaction [20][21]; this method was also used for the preparation of arylated bis-pyrrolotetrathiafulvalenes 2

• moieties directly attached to an aromatic calixarene backbone, we have chosen the copper-catalysed N-arylation reaction as a method for coupling of aromatic and MPTTF moieties with each other and successfully employed it for the preparation of two bis-MPTTF-calixarene conjugates, as well as two model low

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC₆F₄BF₃] and the role of silver-assistance in acceleration of transmetallation

• Vadim V. Bardin,
• Anton Yu. Shabalin and
• Nicolay Yu. Adonin

Beilstein J. Org. Chem. 2015, 11, 608–616, doi:10.3762/bjoc.11.68

• are much more stable and can be isolated [22][23], although for preparative aims they usually are generated in situ. This approach has been successfully used for arylation of alkenes, alkynes, insertion of CO species [23][24][25][26][27][28][29][30][31], polyfluoroarenes and thiophenes [32]. The

Novel stereocontrolled syntheses of tashiromine and epitashiromine

• Loránd Kiss,
• Enikő Forró and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2015, 11, 596–603, doi:10.3762/bjoc.11.66

• 1,3-dipolar cycloaddition and reduction [34] (Figure 3). (−)-Tashiromine has been accessed through the ring closure of difunctionalized acyclic chiral sulfonamide-based β-amino acids [35], the cyclization of pyrrole derivatives with a chiral side-chain [36], or the enantioselective arylation of

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

• Henok H. Kinfe,
• Fanuel M. Mebrahtu,
• Mandlenkosi M. Manana,
• Kagiso Madumo and
• Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

• their profound biological importance, there are different routes reported for their synthesis but the common ones are: nucleophilic substitution of an activated glycosyl donor with organometallic aryl derivatives, cross-coupling of aryls with glycals, Friedel–Crafts arylation at the anomeric centre of

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• enantioselectivity. Since the publication of these results, many different types of chiral dienes have been used in rhodium-catalyzed ECA reactions [148][149]. In 2011, Lin and co-workers reported the rhodium–diene-catalyzed asymmetric 1,4-arylation of γ-lactams [150]. Though He and co-workers previously reported a

• 1,4-arylation of γ-lactams, they obtained the product in moderate yields and good enantioselectivities [151]. When Lin and co-workers were developing their 1,4-arylation procedure, they decided to use a chiral diene because the literature had shown that these ligands provide higher reactivities and

• enantioselectivities than phosphine ligands in rhodium-catalyzed asymmetric reactions [152][153]. Scheme 16 shows the rhodium-catalyzed asymmetric 1,4-arylation that was developed by Lin and co-workers and the subsequent transformation to the GABAB receptor agonist, (R)-(−)-baclofen. Much of the work that has been

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• for the first time. A range of alkenes was arylated in good to quantitative yields in water. The reaction is significantly accelerated when carried out under microwave heating. The arylation of haloalkylacrylates with diazonium salts has been implemented for the first time. Keywords: alkyl cinnamates

• ]. In 2012, examples of the Matsuda–Heck arylation of styrene and acrylic acid esters with arenediazonium tetrafluoroborates in water and catalyzed with in situ formed Pd nanoparticles [5] or agarose-supported Pd nanoparticles [6] have been reported. Superparamagnetic Pd–ZnFe2O4 MNPs have been shown to

• be effective catalysts for the Matsuda–Heck arylation of styrene and ethyl acrylate in water [7]. It is noteworthy that these catalysts are not commercially available and must be synthesized from Pd(OAc)2. Roglands et al. prepared a range of tert-butyl cinnamates and stilbenes from arenediazonium

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• oxidise the nucleophile than the amide precursor. This circumvents the need to prepare, trap and release the N-acyliminium cation under more favourable conditions, allowing the direct α-alkylation or arylation of carbamates (Scheme 3); the cation pool method has been extensively studied [17][18][19][20

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• -arylation. The following conventional cross-coupling or directed C–H arylation resulted in substituted phenanthridines. Homolytic aromatic substitution (HAS) by an aryl radical was used for the construction of biaryl motifs as alternative to transition metal-catalysed C–H bond arylation. That approach was

• . Trying to omit the expensive metal catalysts, several successful attempts of a transition metal-free approach for phenanthridine synthesis were reported. For instance application of a simple diol combined with KOt-Bu resulted in intramolecular C–H arylation to give the respective phenanthridine

Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

• Fatma Belkessam,
• Aidene Mohand,
• Jean-François Soulé,
• Abdelhamid Elias and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 2912–2919, doi:10.3762/bjoc.10.309

• -diheteroarylated thiophenes bearing two different heteroaryl units. Keywords: aryl halides; catalysis; C–H bond activation; direct arylation; heteroarenes; palladium; Introduction 2,2':5',2"-Terthiophene (or 2,5-di(2-thienyl)thiophene) (Figure 1) and many of its derivatives are important structures due to their

• ][9][10][11][12][13][14][15][16]. However, an organometallic derivative must be prepared to perform such reactions. In 1990, Ohta and co-workers reported the Pd-catalyzed direct arylation of heteroaromatics using aryl halides as coupling partners via a C–H bond activation [17][18]. Since then Pd

• -catalyzed direct arylation of heteroaryls, especially with aryl halides as coupling partners, has been shown to be a very powerful method for an easier and greener access to a very broad range of arylated heterocycles [19][20][21][22][23][24][25][26][27][28][29][30][31][32]. This method is more attractive

Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

• László Tóth,
• Yan Fu,
• Hai Yan Zhang,
• Attila Mándi,
• Katalin E. Kövér,
• Tünde-Zita Illyés,
• Attila Kiss-Szikszai,
• Balázs Balogh,
• Tibor Kurtán,
• Sándor Antus and
• Péter Mátyus

Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272

• out according to the procedure of Litkey and Patonay [18] affording the racemic 3,4-dihydro-2-phenyl-1,4-benzoxazepine-5-one (rac-9) with high regioselectivity, which was reduced to (rac)-10 with LAH in dry THF. In the following step, the N-arylation of rac-10 was performed through a nucleophilic

A simple copper-catalyzed two-step one-pot synthesis of indolo[1,2-a]quinazoline

• Chunpu Li,
• Lei Zhang,
• Shuangjie Shu and
• Hong Liu

Beilstein J. Org. Chem. 2014, 10, 2441–2447, doi:10.3762/bjoc.10.254

• Ullmann condensation is a powerful method for C–N coupling [24][25][26], especially the N-arylation of nitrogen-containing heterocycles such as indoles [27][28]. Indolo[1,2-a]quinazoline is a kind of tetracyclic compounds containing the indole motif that has been constructed by intramolecular [3 + 2

• domino cyclization. Based on the previous work for the copper-catalyzed synthesis of 2-amino-1H-indole derivatives and copper-catalyzed N-arylation, we herein report a simple and efficient one-pot method to synthesize indolo[1,2-a]quinazolines by a sequential Ullmann-type C–C and C–N coupling. Compared

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• -diarylindoles were successfully reacted with N-Boc-THIQ to furnish 1,2,3-trisubstituted indoles as target compounds. Furthermore, regioselective N-arylation of protected and unprotected 1-(indol-3-yl)-THIQs was successfully conducted using either simple iron or copper salts as catalysts. Keywords: Buchwald

• –Hartwig coupling; C–C coupling; C–H functionalization; iron catalysis; regioselective arylation; Introduction 1,2,3,4-Tetrahydroisoquinolines (THIQs) are common substructures in natural products [1]. The structural motif of 1-(indol-3-yl)-THIQ is also found in compounds with biological activity, for

• well established via a series of transformations. The direct arylation via C–H functionalization represents a very efficient approach in this regard [24][25][26][27][28][29][30][31] with methods available to either decorate position 2 or 3 regioselectively [32][33][34][35][36][37][38][39][40][41][42