Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• using various electrophiles such as alkyl halides [13], vinyl halides [14][15][16], aryl halides [17][18] and epoxides [19][20] in homogeneous solutions (Figure 1b). 1-2. Design of biomimetic and bioinspired B12 catalytic systems Schematic representations of B12 enzymes and enzyme-involving systems are

Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

• Amrita Das,
• Mitasree Maity,
• Simon Malcherek,
• Burkhard König and
• Julia Rehbein

Beilstein J. Org. Chem. 2018, 14, 2520–2528, doi:10.3762/bjoc.14.228

• prefunctionalized sulfenylating reagents. Recently Lei and co-workers reported a DDQ-mediated selective radical–radical cross coupling between electron-rich arenes and thiols [40]. Miyake et al. reported the visible light-promoted cross-coupling reaction between aryl halides and arylthiols via an intermolecular

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

• 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

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• carboxylation of aryl halides and pseudohalides using CO2 is an important reaction to yield benzoic acid derivatives. In 2009, Martin reported the Pd-catalyzed carboxylation of aryl bromides using ZnEt2 as the reductant [31]. In 2012, we first reported the Ni-catalyzed carboxylation of aryl chlorides and vinyl

• . found the direct carboxylation reaction with CO2 under photo-irradiation reaction conditions [46]. Jamison et al. also reported the synthesis of α-amino acid derivatives using amine and CO2 [47]. Iwasawa disclosed the Pd-catalyzed carboxylation of aryl halides using CO2 in the presence of an Ir photo

Synthesis of indolo[1,2-c]quinazolines from 2-alkynylaniline derivatives through Pd-catalyzed indole formation/cyclization with N,N-dimethylformamide dimethyl acetal

• Antonio Arcadi,
• Sandro Cacchi,
• Giancarlo Fabrizi,
• Francesca Ghirga,
• Antonella Goggiamani,
• Antonia Iazzetti and
• Fabio Marinelli

Beilstein J. Org. Chem. 2018, 14, 2411–2417, doi:10.3762/bjoc.14.218

• -catalyzed reaction of o-(o-aminophenylethynyl) trifluoroacetanilides 5 with aryl halides and aryldiazonium salts led to the formation of 12-arylindolo[1,2-c]quinazolin-6(5H)-ones 8 in moderate to excellent yields (Scheme 2a) [23]. Very likely, under these reaction conditions, the palladium-catalyzed

• )anilines 15 (see below). Results and Discussion We have previously reported that arylboronic acids 12 can be used in place of aryl halides in the Pd-catalyzed synthesis of indoles through aminopalladation/reductive elimination reaction from 2-alkynyltrifluoroacetanilides [24]. This reaction is carried out

D-Fructose-based spiro-fused PHOX ligands: synthesis and application in enantioselective allylic alkylation

• Michael R. Imrich,
• Jochen Kraft,
• Cäcilia Maichle-Mössmer and
• Thomas Ziegler

Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182

• nitrile is slower compared to the unstabilized 9b. The Stoltz and co-workers reported the preparation of a series of PHOX ligands using Buchwald’s copper-catalyzed C–P bond construction [48][49]. This reaction allows the Ullmann coupling of aryl halides with secondary phosphines to afford tertiary

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• reduction of aryl halides to the corresponding non-halogenated aromatics. This was extended to the coupling of aryl halides to a variety of substituted pyrroles, using N,N-bis(2,6-diisopropylphenyl)perylene-3,4,9,10-bis(dicarboximide) (PDI) as the photocatalyst, under blue LED irradiation, in DMSO and in

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

• for subsequent synthesis, as it has been reported that organotrifluoroborates may also be employed as starting materials in Suzuki–Miyaura coupling reactions of aryl halides [52][53]. Indeed, starting from benzo[b]quinolizinium-9-trifluoroborate (3b) and the corresponding aryldiazonium ions the 9

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

• coupling reaction is a powerful method for the synthesis of ubiquitous biaryls and has been extensively employed in the synthesis of natural products, pharmaceuticals, agrochemicals, and polymers. The reaction usually involves a palladium-catalysed coupling of aryl boronates with aryl halides in organic

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

• , their reactivity is higher than that of the corresponding aryl halides, a property that has been widely exploited to develop efficient transition-metal-catalyzed cross coupling reactions [55]. The latter, however, allow for transferring only one of the two aromatic motifs of the iodonium reagents

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• phosphinoferrocenyl-substituted calixarene ligands 27–29. Asymmetric coupling reaction of aryl boronates and aryl halides in the presence of calixarene mono and di(ferrocenylphosphine) ligands 27 and 28. Asymmetric allylic alkylation in the presence of calix[4]arene ligand (S,S)-29. Asymmetric Tsuji–Trost reaction in

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

• application of a Pd-catalyzed Buchwald–Hartwig amination. In recent years, extensive efforts have been made on the Pd(0)-catalyzed amination of aryl halides or triflates in order to achieve the efficient synthesis of substituted anilines [6][7][8][9]. Buchwald et al. stated that the Pd source is determining

Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib

• Jingbo Yu,
• Zikun Hong,
• Xinjie Yang,
• Yu Jiang,
• Zhijiang Jiang and
• Weike Su

Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66

• reagent in the reaction, the substrate 1a was converted to 4a in 27% yield (conditions a), while the dehalogenation was exacerbated in the presence of Pd(OAc)2/PPh3 (conditions b). This phenomenon was in agreement with previous reports [14][15][16], that Pd-catalyzed homocoupling of aryl halides under

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• unstable [Pd(allyl)Cl]2 intermediate from air. Micelles were also used to perform cross-coupling between benzyl and aryl halides in water [65]. This reaction is known to result in very limited yields due to the undesired homo-coupling reaction between electron-rich and electron-poor benzyl bromides [69

• et al. described a nanogel composed of poly(N-isopropylacrylamide) brushes grafted on Pd-NPs (Pd@PNIPAM) to carry out coupling reactions in water under mild conditions [120]. They showed highly efficient coupling of several hydrophobic aryl halides with phenylboronic acid, which in all cases resulted

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

• , Pd-catalysed C–C cross-coupling reactions have become indispensable in many modern synthetic protocols both in the laboratory and on an industrial scale. A highly important representative of this class of transformation is the Suzuki–Miyaura reaction [5][6], involving the coupling of aryl halides

Palladium-catalyzed ortho-halogenations of acetanilides with N-halosuccinimides via direct sp² C–H bond activation in ball mills

• Zi Liu,
• Hui Xu and
• Guan-Wu Wang

Beilstein J. Org. Chem. 2018, 14, 430–435, doi:10.3762/bjoc.14.31

• corresponding N-halosuccinimides. Keywords: acetanilide; ball milling; C–H activation; halogenation; mechanochemistry; N-halosuccinimide; palladium catalysis; Introduction Aryl halides have been widely utilized in organic syntheses, which give access to a range of complex natural products [1][2]. However

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• . Trifluoromethylation of aryl halides using trifluoroacetates as the trifluoromethyl source Reactions employing expensive electrophilic CF3 species such as Umemoto’s reagent or Togni’s reagent, were unpractical and limited on a large-scale synthesis. After comparison of the prices of different CF3 reagents, attention

• . Trifluoromethylation of aryl halides using difluorocarbene precursors as the trifluoromethyl source The trifluoromethyl sources employed in the above-mentioned trifluoromethylations were mainly CF3-containing reagents. Besides, some examples employing difluorocarbene precursors as the trifluoromethylation reagents

• aryl halides in the past years. In contrast, successful examples of copper-catalyzed trifluoromethylation of alkyl halides are quite limited. In 2011, the group of Shibata [25] firstly reported the copper-mediated chemoselective trifluoromethylation at the benzylic position with shelf-stable

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

• conditions were not suitable for aliphatic alkynes as they do not undergo oxidative addition with the [NiI] sulfide complex. Miyake and co-workers described a very different approach for the C–S cross-coupling between aryl thiols and aryl halides (Scheme 24) [59]. In a mixture with caesium carbonate as a

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

• 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

• examples of Pd-catalyzed direct arylations via the C–H bond activation of selenophenes using aryl halides as coupling partners have been reported [32][33][34][35]. Conversely, C–H bond activation methodology was employed in only in one case for the preparation of a heteroarylated selenophene from a

• , respectively. The use of 2-pentyl- and 2-chlorothiophenes also gave the desired products 10 and 11 in high yields. In general, the Pd-catalyzed direct arylation of 3-substituted thiophenes with aryl halides afforded quite regioselectively the C2-arylated thiophenes [30]. A similar regioselectivity was oberved

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• bear the trifluoromethyl group have great importance in the life sciences and materials fields as well as discovery chemistry in general [1][2][3]. Consequently, transition-metal-catalyzed methods for preparing aromatic trifluoromethyl compounds from readily available aryl halides are an area that has

• seen rapid growth in the past ten years. Copper is one of the most successfully used metals for mediating the trifluoromethylation of aryl halides, and the active form of the reagents is typically a copper(I) complex bearing a trifluoromethyl ligand, i.e., [LnCu–CF3]. Sporadic examples of

• facilitate meaningful comparative studies, such as structural and electrochemical ones [2]. N-Heterocyclic carbene (NHC) complexes of copper such as A1 (Scheme 1) were the first well-defined and structurally characterized copper–CF3 complexes that display activity for the trifluoromethylation of aryl halides

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

• palladium salts (Pd(OAc)2 or Pd(PPh3)4) and DABCO (1,4-diazabicyclo[2.2.2]octane) various acetylenes and aryl halides were coupled to obtain the Sonogashira coupling products in excellent yields (near quantitative, Scheme 10a). The reactions were reported for aliphatic alkynes as well. In Scheme 10b, an

• significant in organic synthesis because aryl halides are important synthons for the synthesis of many natural and non-natural products [93][94]. In 2005, Rahman and co-workers reported a pioneering solid state benzylic bromination of diquinoline derivatives via N-bromosuccinimide (NBS) [95]. In 2012, Wang

Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz–Fritsch–Bobbitt reaction with non-activated and moderately-activated systems

• Marco Mottinelli,
• Mathew P. Leese and
• Barry V. L. Potter

Beilstein J. Org. Chem. 2017, 13, 1871–1878, doi:10.3762/bjoc.13.182

• aforementioned aims, we envisaged that the synthesis set out in Scheme 2 could deliver access to substrates for the PFB reaction such as 9. After an initial, unfruitful, attempt to obtain the aminoacetals 9 from sequential condensation of aniline and alkyl and aryl halides, a double reductive alkylation that

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

• , Jadavpur, Kolkata 700032, India. Fax: +91 33 24730957; Tel: +91 33 23223403 10.3762/bjoc.13.174 Abstract The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols using nickel nanoparticles (Ni NPs) supported on reduced graphene oxide (Ni/RGO) as a heterogeneous

• formic acid at room temperature [48]. Also, it can serve as an excellent catalyst for the Kumada–Corriu C–C cross-coupling reaction [49]. Since heterogeneous Ni catalysts are rarely studied for the C–S cross-coupling reaction between aryl halides and thiols, presumably because of the fact that the thiols

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• nanocatalyst. Thus, a variety of aryl halides 1a–h and olefins 2a–c were screened, employing the best reaction conditions above obtained (0.5 mmol of K2CO3, H2O/EtOH, at 130 ºC, Table 2). In all cases, clean and high selective reactions to obtain the trans-products were achieved. By using styrene (2a) and aryl

• perform the coupling reaction between a wide range of aryl bromides and different alkenes. Besides, with demanding substrates like heterocycles, ortho-substituted and non-activated aryl halides, very good results were achieved. Finally, the reusability of PVP-Pd NPs was evaluated in the reaction between 4

• : 10 min; 2º cycle: 20 min; 3º cycle: 30 min, 4º cycle: 30 min, 5º cycle: 30 min. Synthesis of (E)-pterostilbene (19) catalyzed by PVP-Pd NPs. Reaction condition optimizations.a Mizoroki–Heck reaction of aryl halides with olefins catalyzed by PVP-Pd NPs.a Stille–Heck tandem reaction of aryl halides

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• of the mannosyl donor in three steps and 46% overall yield [64]. 3.4.2 Stereospecific Pd-catalyzed glycosylation: In 2016, Walczak and colleagues [65] described the Pd-catalyzed glycosylation of arenes using anomeric stannanes as donors and aryl halides as the acceptors. The reaction appears to be

• perfectly stereospecific as complete retention of the stereochemistry was observed in all cases. The initial scope used a benzyl-protected glucosylstannane as the donor and a series of aryl halides as acceptors and in all instances the reaction was stereoretentive (Scheme 19) although a mechanistic