Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• % yield via a gold/silver catalyst system (Scheme 27). 4 Oxidative C–C coupling Whereas oxidative C–C coupling precedes amination in the industrial route to 5H-dibenzo[b,f]azepine, oxidative C–C coupling may also be the final step in the construction of the dibenzo[b,f]heteropine skeleton. Comber and

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

•  18B). An interesting idea realized in this process is the alcohol activation for α-hydrogen atom abstraction by hydrogen bonding between the alcohol OH group and dihydrophosphate anions. It should be noted that alcohol-derived α-hydroxy radicals frequently do not undergo successful C–C coupling due to

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• formal elimination of H2. This section is categorized by the initiating step and the types of bonds being formed. Denitrogenative C–C/C–C coupling In 2014, Yu’s and Du’s groups independently described the arylcarbonylation of alkenes for the synthesis of oxindoles 118 from N-alkyl,N-arylacrylamides 60

• 120. Homolytic-cleavage-initiated C–C/C–C coupling In 2018, Du and co-workers explored the decarboxylative radical addition/cyclization of tert-butyl peresters 129 and N-arylacrylamides 60 for the synthesis of oxindoles 130 (Scheme 26) [118]. The scope of the reaction was broad and tolerated a variety

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• -catalyzed C–H activation Scandium is the first metal of the 3d metals row. It is relatively cheap compared to heavier transition metals, and it is commonly used on catalytic procedures, such as catalyzed polymerization [31][32] and C–C coupling reactions [33][34]. It is also an increasing metal option to

An atom-economical addition of methyl azaarenes with aromatic aldehydes via benzylic C(sp³)–H bond functionalization under solvent- and catalyst-free conditions

• Divya Rohini Yennamaneni,
• Vasu Amrutham,
• Krishna Sai Gajula,
• Rammurthy Banothu,
• Murali Boosa and
• Narender Nama

Beilstein J. Org. Chem. 2020, 16, 3093–3103, doi:10.3762/bjoc.16.259

• -dimethylpyridine (1a) and 1 mmol p-nitrobenzaldehyde (2a) at 135 °C for 24 h in a sealed vial without any catalysts or additive under solvent-free conditions. Thereupon, these optimized conditions were utilized to validate the substrate scope of this direct C–C coupling reaction. A variety of aldehydes, 2a–r, was

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• complexes enabling a simpler recovery and reuse of the catalysts by filtration [5]. Furthermore, the immobilized NHC-complexes can be easily adapted to flow processes using a fix-bed reactor set-up increasing simultaneously the sustainability and the efficiency of the C–C coupling reactions [6][7]. In the

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• cycle for the C–C coupling. The coupling reaction follows a radical–anion mechanism due to the presence of electron-donating ligand 12 and this is the key feature allowing preferential binding of the phenoxyl radicals for PCET. Products arising from homo- and heterocouplings were formed with high

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

• (R = Me, iPr and Ph) in benzene produced chiral acetal 22. Subsequent palladium-catalyzed C–C coupling of the acetal with 4-fluorophenylboronic acid (FPBA) in the presence of caesium carbonate and tri-tert-butylphosphine afforded aryl fluorides 23. Pure ligands 24 (63–72%) were obtained by

Functionalization of the imidazo[1,2-a]pyridine ring in α-phosphonoacrylates and α-phosphonopropionates via microwave-assisted Mizoroki–Heck reaction

• Damian Kusy,
• Agata Wojciechowska,
• Joanna Małolepsza and
• Katarzyna M. Błażewska

Beilstein J. Org. Chem. 2020, 16, 15–21, doi:10.3762/bjoc.16.3

• heterogeneous and homogeneous catalysts, as well as continuous-flow conditions [13][14][15]. Therefore, we tested microwave heating, a technique which is known for significant acceleration of the C–C coupling reaction [16]. We carried out the optimization studies using model substrates – compound 1a and benzyl

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion

• Christina Görgen,
• Katharina Boden,
• Guido J. Reiss,
• Walter Frank and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1360–1370, doi:10.3762/bjoc.15.136

• -hydroxypyrazolines in moderate to good yields. The structures were unambiguously corroborated by comprehensive NMR spectroscopy and X-ray structure analyses of selected derivatives. Keywords: activation; alkynylation; C–C coupling; copper; cyclization; multicomponent reactions; Introduction Pyrazoles [1][2] and

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

• Sebastian Haferkamp,
• Andrea Paul,
• Adam A. L. Michalchuk and
• Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

• monitoring multi-phase reactions during ball milling. Keywords: ball milling; C–C coupling; in situ; mechanochemistry; multivariate data analysis; Introduction Mechanochemistry offers a wide array of applications. It is used widely for synthesis of inorganic, metal-organic, and organic molecules and

• materials [1]. Interest in these methods stems largely from the fact that they are efficient and more environmentally friendly as compared to traditional approaches [2][3]. Mechanochemistry is a well-established method for the synthesis of coordination polymers, the formation of cocrystals, and in C–C

• coupling reactions [4][5][6][7]. Despite the increasing use of mechanochemistry, there is still a lack in understanding of the underlying processes involved during mechanically-facilitated reactions. This is particularly true of the potential role of transient polymorphic phases [8] and seeding effects [9

Synthesis of functionalized diazocines for application as building blocks in photo- and mechanoresponsive materials

• Widukind Moormann,
• Daniel Langbehn and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 727–732, doi:10.3762/bjoc.15.68

• oxidative C–C coupling of 2-nitrotoluenes (75–82% yield) and a reductive ring closure to form the diazocines (56–60% yield). The cyclization of the dinitro compound to the azo compound was improved in yield and reproducibility, by over-reduction to the hydrazine and reoxidation to the azo unit. In contrast

• molecular switches in photo and mechanoresponsive macromolecules and other smart materials. Keywords: bridged azobenzene; diazocine; mechanophor; oxidative C–C coupling; photochrome; reductive azo cyclization; Introduction The field of photoresponsive materials is of growing interest [1][2][3]. Several

• coupling of nitrotoluenes and the reductive ring closure of the dinitro compounds (Scheme 1). We recently improved the yield of the C–C coupling through addition of bromine as an oxidizing agent [27]. The reaction times thus are reduced to several minutes as compared to several hours in previous procedures

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• the examples shown in Scheme 14 [33]. Nonaflate PM54 underwent a Suzuki–Miyaura reaction to PM55 or a Sonogashira coupling to PM56 under standard conditions. The ethynyl-substituted pyrimidine derivative PM12 could also be employed in C–C coupling reactions as shown by its connection to pyridyl

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

• )–2.05(2) Å) than with chlorosilanol 8 (OH···2.16(0) Å). Due to its two hydroxy units, the silanediol 9 shows higher catalytic activity as hydrogen bond donor than chlorosilanol 8, e.g., C–C coupling N-acyl Mannich reaction of silyl ketene acetals 11 with N-acylisoquinolinium ions (up to 85% yield and 12

• used for the C–C coupling in the N-acyl Mannich reaction with activated isochinolin 10, 1-chloroisochroman (18) and chromone 21 with different silyl ketene acetals. Due to more efficient bifunctional Si(OH)2-hydrogen bonding, silandiol 9 tops chlorosilanol 8, also on catalytic application

• yielding C–C coupling product 12 [45][47]. Synthesis of BIFOXSiCl2, starting with BIFOL (5) [52][54] yielding dichlorosilane 7. Hydrolysis of BIFOXSiCl2 (7) yielding the corresponding silanediol 9 and controlled hydrolysis of BIFOXSiCl2 (7) to BIFOXSiCl(OH) (8). For solvent mixtures and temperatures see

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

• C–C coupling reactions, is to consider the ability of organocatalysed photoredox reactions to perform reactions which create C–X (X = N, O, S) bonds, in reactions analogous to Buchwald or Chan–Lam couplings. An example of the creation of C–S bonds is given by Wang and co-workers, who have reported

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

• functionalization are necessary. In this context, Palladium-mediated cross-coupling reactions provide a powerful tool [21][22][23][24][25][26][27]; specifically, as these C–C coupling reactions have been demonstrated to be very useful for the introduction of various substituents to quinolizinium [28][29][30][31][32

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

• investigation of the mechanism of the reaction revealed that a Pd(II) to Pd(IV) route is the more likely pathway which was further supported by computational studies. Keywords: cationic palladium(II) complexes; Pd(II)/Pd(IV) complexes; SNS pincer complexes; Suzuki–Miyaura; Introduction The Suzuki–Miyaura C–C

• 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

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

• -estrone 3-methyl ethers are also effective inhibitors [19]. Recently, we carried out the Pd-catalyzed C–C coupling of 2- and 4-iodo-13α-estrones as well as their 3-methyl ethers with p-substituted phenylacetylenes as terminal alkyne partners under microwave irradiation [20]. The regioisomerism markedly

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• . Diketone 30 was prepared in a straightforward manner by C-C-coupling of nitrosoalkene NSA7 (generated in situ from the corresponding α-bromooxime 31) with silyl enolate of 2-methylcyclopentanone, and subsequent deoxygenation of the resulting oxime 32 with CAN. Unfortunately, attempts to convert pentalenone

• nitrosoalkenes. Precursors of nitrosoalkenes NSA. Reactions of cyclic α-chlorooximes 1 with 1,3-dicarbonyl compounds. C-C-coupling of N,N-bis(silyloxy)enamines 3 with 1,3-dicarbonyl compounds. Reaction of N,N-bis(silyloxy)enamines 3 with nitronate anions. Reaction of α-chlorooximes TBS ethers 2 with ester

Mechanochemical Knoevenagel condensation investigated in situ

• Sebastian Haferkamp,
• Franziska Fischer,
• Werner Kraus and
• Franziska Emmerling

Beilstein J. Org. Chem. 2017, 13, 2010–2014, doi:10.3762/bjoc.13.197

• process both result in crystalline products suitable for single crystal X-ray diffraction. Keywords: ball milling; C–C coupling; in situ; Knoevenagel condensation; mechanochemistry; Introduction Mechanochemical syntheses have gained increasing popularity in different areas such as materials science

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• getting reduced in situ in the presence of Et3N and Ph3P to Pd(0) [13][20], which is the reactive species for the dimerization. Then, two molecules of isoprene coordinate to the Pd-metal center (species I). Upon the C–C coupling between the two isoprene units, a Pd-(η1,η3-dimethyloctadiendiyl)-complex of

Synthesis of novel 13α-estrone derivatives by Sonogashira coupling as potential 17β-HSD1 inhibitors

• Ildikó Bacsa,
• Rebeka Jójárt,
• János Wölfling,
• Gyula Schneider,
• Bianka Edina Herman,
• Mihály Szécsi and
• Erzsébet Mernyák

Beilstein J. Org. Chem. 2017, 13, 1303–1309, doi:10.3762/bjoc.13.126

• -catalyzed C–C coupling reactions. Some Sonogashira couplings on estrane, but not on the 13α-estrane core have been performed at C-2, -3, -11, -16 and -17. To the best of our knowledge, 4-coupled regioisomers have not been synthesized to date [19]. Couplings of steroidal alkynes with small molecular halides

• C–C coupling. 13α-Estrone 3-methyl ether 2 possesses a weaker inhibitory effect than the 3-hydroxy compound 1. Iodination or phenylalkynylation at C-2 diminishes inhibition of 2. Introducing iodine onto C-4 of compound 2 leads to a 10-fold decrease in its IC50 value. 4-Phenylalkynyl derivatives 10

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

• transition state. For the C–C coupling in the 12F → TS3 reaction, the C,C distance in the reactant is 2.958 Å, which is reduced to 2.475 Å in the transition state (Figure 4). Thus, for the reaction sequence with 8, the lowest free energy barrier is found for the initial C–C coupling leading to the diradical

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

• activities in the coupling reaction of aryl chlorides. Keywords: aryl chloride; geometry-constrained; iminopyridyl; palladium; Suzuki; Introduction Palladium-promoted C–C coupling reactions are recognized as one of the most powerful tools in organic syntheses, pharmaceutical processes and biological