Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• reactants such as amines, alcohols or aldehydes led to a wide range of products as reported in Scheme 17. Ley's group developed several continuous-flow approaches for generating diazo species from hydrazones [84][85]. Under flow conditions, diazo compounds were reacted with boronic acids in order to

• generate reactive allylic and benzylic boronic acids further employed for iterative C–C bond forming reactions [86]. The generation of unstable diazo species was possible using a cheap, recyclable and less toxic oxidant, MnO2. The flow stream was accurately monitored by in-line FTIR spectroscopy in order

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• , entries 13). Different arylboronic acids were also examined to react with 4-chloroacetophenone in this system. No matter what kind of boronic acids were used: electron-deficient (Table 4, entry 14), electron-rich (Table 4, entries 15 and 16) or sterically hindered (Table 4, entry 17) arylboronic acids

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

• were tolerated and yielded the desired product in 80% yield (3f). Aromatic boronic acids possessing both electron-withdrawing and electron-donating substituents were evaluated under our reaction conditions and all resulted in good yields. While aromatic boronic acids substituted with electron

• -withdrawing groups (e.g., acyl, F or CF3) were likewise tolerated well (3g–j). Aromatic boronic acids substituted with electron-donating groups resulted in the formation of the corresponding arylated products with higher yields (3k–n). Enantioselective arylation reaction Subsequently, we explored the

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

• Arne Klinkebiel,
• Ole Beyer,
• Barbara Malawko and
• Ulrich Lüning

Beilstein J. Org. Chem. 2016, 12, 2267–2273, doi:10.3762/bjoc.12.219

• the Suzuki–Miyaura coupling [11]. A retrosynthetic analysis (Figure 3) of extended mono-functionalized triazinetricarboxylic acids 2 calls for tris(4-bromoaryl)-1,3,5-triazines 3 and boronic acids 4 with an additional carboxylic acid functionality. The respective methyl carboxylate of boronic acid 4

• 5c. The resulting triazines 3b and 3c can then be coupled to boronic acids or boronates to give substituted and elongated triazine-based linkers. Furthermore, the reduction of the nitro group or cleavage of the methoxy group will give additional substituted linkers, amino and hydroxy-substituted ones

• boronic acids 4. Synthesis of unsymmetrically substituted 2,4,6-tris(bromoaryl)-1,3,5-triazines 3 from one equivalent of a substituted benzoyl chloride 5 and two equivalents of benzonitrile 6. As intermediates, oxadiazinium salts 7 are formed. The reaction with ammonia yields the desired triazines 3

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

• Maddali L. N. Rao,
• Jalindar B. Talode and
• Venneti N. Murty

Beilstein J. Org. Chem. 2016, 12, 2065–2076, doi:10.3762/bjoc.12.195

• stage that in comparison to similar cross-couplings carried out with aryl boronic acids [29], the present method with triarylbismuth reagents showed appreciable reactivity with threefold coupling advantage and extended substrate scope. The overall resulted regio- and chemo-selective couplings encouraged

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

• for C(aryl)–N and C(aryl)–O coupling reactions. Their methods made use of stoichiometric amounts of copper(II) acetate as the catalyst and boronic acids as the aryl donors. In the presence of a base, the coupling could be performed at room temperature. These reactions were subsequently shown to work

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

• , whereupon it reacts with another equivalent of arylurea (Scheme 17) [231]. Similarly, BQ’s role in C–H coupling of boronic acids would likely be to oxidize Pd(0) to Pd(II) after the product forming step (Scheme 18). Transmetallation between the palladacycle and arylboronic acid followed by reductive

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

• construction of unsymmetrically arylated pyrroles, thiophenes and 2,6- and 3,5-diarylpyridines. In order to test the utility of the above mentioned approach, a series of trial cross couplings were performed on a microscale according to route 3 with a variety of electron-poor and electron-rich boronic acids

• (Table 2). The steric hindrance introduced by ortho-substituted boronic acids was also investigated. In order to check how the electronic and steric factors affect the distribution of homo- and heteroarylated products, various combinations of arylboronic acids (32–41) were applied as partners for the

• coupling of 3,5-, 2,6-dibromopyridines and dibromobenzenes with various arylboronic partners of different electronic properties. We then investigated a one-pot, double cross-coupling strategy with mixtures of more sterically demanding boronic acids containing ortho-substituents. The cross coupling of 1

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

• lower than that of the corresponding boronic acids. Because of this lower reactivity, several transformations require deprotection of a pinacol ester under oxidative conditions (e.g., NaIO4) [16]. Hartwig reported that the Ir/dtbpy system is also able to introduce more reactive neopentyl and hexylene

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

• . Recently, we reported a copper-catalyzed C–C bond formation by substitution of the labile C(4)SMe group in 4H-chromenes or C(3)–OH in isoindolinones with aryl/alkenyl groups by employing the corresponding boronic acids [51][52]. Continuing these efforts, we designed a copper-catalyzed synthesis of a

• further step with a variety of aryl boronic acids), it should be possible to provide a unique opportunity for the modular synthesis of unsymmetrical triarylmethanes. If successful, the method could provide an opportunity for the synthesis of a combinatorial library of the coveted molecules. Herein, we

• towards electronic effects, the copper-mediated cross-coupling reaction is not very sensitive to steric crowding in the neighborhood of the reaction center. Next, we employed heteroaromatic boronic acids, such as furan-2-ylboronic acid (10i; Table 2, entry 8), thiophen-2-ylboronic acid (10j; Table 2

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• Prize in 2013 and I was recently rewarded for developing networks with China with an Inaugural CASE Prize in 2015. Keywords: boronic acids; fluorescence; glucose sensor; self and directed assembly; supramolecular; Review Beginnings When at school I became distracted very easily and while this may not

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• 1992, and looking back at the polyol receptors (such as 3) shows how far this field progressed. The use of boronic acids of Shinkai/James (7) [43][44][45] and the large cavities reported by Davis (8) [46] for binding saccharides has advanced the field far beyond our primitive designs (Figure 6). The

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

• , Aβ peptide pentapeptide boronic acids 1 and 2 were synthesized by solid-phase peptide synthesis and studied in esterification experiments with polyhydroxylated templates. The bis-hydroxylated dipeptide Hot=Tap serves as a template of adjustable degree of oligomerization which spontaneously forms

• avoided only when two different reactive groups are employed; that is why the reversible esterification between boronic acids and diols appeared an attractive solution to us. In a first approach, we planned to condense short peptide boronic acids with polyol templates for the assembly of an Aβ-dimer. The

• -terminal boronic acid 2. Peptide boronic acids of type 1 were synthesized on polymer-bound diethanolamine (PS-DEAM resin), according to the protocol in Supporting Information File 1, Figure S1 [21]. The electron-poor boronic acid 2, which was expected to be more reactive in boronic ester formation, was

Rhodium, iridium and nickel complexes with a 1,3,5-triphenylbenzene tris-MIC ligand. Study of the electronic properties and catalytic activities

• Carmen Mejuto,
• Beatriz Royo,
• Gregorio Guisado-Barrios and
• Eduardo Peris

Beilstein J. Org. Chem. 2015, 11, 2584–2590, doi:10.3762/bjoc.11.278

• 2 is lower than that shown by complex 6, both in terms of conversion and selectivity. For all reactions carried out in the presence of catalyst 2, deborylation of the boronic acids took place. This side reaction explains the differences found between conversions and yields for all reactions

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• , substituted pyridine boronic acids [52][53][54] were coupled with intermediate 26 using Method III in DME–water to provide the desired 6-aryl products 37–40 (entries 12–15, Table 1). These results indicated that the DME–water solvent system was more favourable for more challenging Suzuki C–C coupling

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

• literature describes the synthesis of 3- or 4-(pentafluorosulfanyl)phenylboronates or boronic acids from SF5-bromobenzenes via lithiation or magnesiation. These approaches suffer from low yields and other drawbacks [70][71]. For lithiation of the aryl bromide, t-BuLi had to be used and the formation of

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• oligofluorenylboronic acids FnB (n = 1–4), synthesised by a known procedure [19], was used as the precursors for the nucleophilic coupling reagent. In the case of the T-Bn series, the convergent strategy was used for the synthesis of T-B1–T-B3 compounds using Suzuki coupling of the aforementioned oligofluorenyl boronic

• acids FnB (n = 1–3) with the core precursor compound T-B0Br [33], using conditions which proved to be efficient for coupling of BODIPY derivatives [30] (Scheme 2). The yields observed were 29–58%. Conversely, the T-B4 member of the series was synthesised by a semi-convergent approach, firstly via Suzuki

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

• temperature under acidic conditions, employing boronic acids as aryl source [59]. Using this method the desired product 6a could be obtained but only in a low yield of 36% (Table 2, entry 1). Besides 6a also 12% of biphenyl could be isolated. Increasing the temperature to 50 °C proved to be counterproductive

• transformation. Obviously the steric bulk of the THIQ substituent in 3-position makes this transformation quite difficult. Hence it was decided to stick with the so far best conditions to investigate the scope of C2-arylation, the first step of route B (Scheme 2). Using substituted boronic acids led to decreased

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• successfully prepared [19]. The Suzuki cross-coupling is particularly suitable for carbohydrate chemistry due to the mild reaction conditions and its tolerance to a variety of functional groups [20]. In addition, the reactions are easy to perform and the required boronic acids exhibit exceptional stabilities

A convenient enantioselective decarboxylative aldol reaction to access chiral α-hydroxy esters using β-keto acids

• Zhiqiang Duan,
• Jianlin Han,
• Ping Qian,
• Zirui Zhang,
• Yi Wang and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 969–974, doi:10.3762/bjoc.10.95

• stereocontrolled nucleophilic alkylation [15][16][17][18][19], alkynylation [20][21], 1,2-addition [22][23][24][25][26] and aldol reaction [27][28][29][30][31][32] have been developed. Various nucleophiles such as organometallics, boronic acids and unsaturated ketones can be tolerated in this context (Figure 2

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C₃₆H₁₂ open geodesic polyarene

• Hee Yeon Cho,
• Ronald B. M. Ansems and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

• available boronic acids. The reaction proceeds smoothly with 2-bromophenylboronic acid in the presence of Pd(0) and a base to furnish 29 (Scheme 9). The Suzuki reaction proceeds reasonably well, despite the potential complication of the product undergoing a subsequent Suzuki coupling with the bromine of the

Clean and fast cross-coupling of aryl halides in one-pot

• Valerica Pandarus,
• Geneviève Gingras,
• François Béland,
• Rosaria Ciriminna and
• Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

• involves a boron-containing nucleophile (a variety of aryl and heteroaryl boronic acids, esters, Ar-BBN, trifluoroborate and other boron species) and vinyl- or aryl halides as the electrophilic species. The use of the Suzuki–Miyaura reaction became routine both in industry and in research laboratories

• 80 °C in dioxane or in DMSO. In contrast to a number of Pd catalysts that are air sensitive, PdCl2(dppf) is air stable. This made the method more versatile and provided a long awaited easy way to synthesize a broad range of boronic esters that are conveniently used in place of boronic acids in the

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• and (E)-styrylboronic acid [12]. This was the first report of this type of transformation, which is now referred as the Petasis borono–Mannich reaction, and was later extended to a wide variety of other aldehydes, such as glyoxylic acid (for example), boronic acids, esters or trifluoroborates and

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

• . 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