Asymmetric organocatalytic Michael addition of cyclopentane-1,2-dione to alkylidene oxindole

• Estelle Silm,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2022, 18, 167–173, doi:10.3762/bjoc.18.18

• . Also, a higher C–H acidity of the proton at the stereogenic centre and possible racemisation can’t be excluded. A heteroaromatic oxindole derivative afforded the product 3j in lower yield and high ee values. 4- and 5-bromo oxindole derivatives (2l and 2k, respectively) were also used as starting

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

• Takayoshi Kasakado,
• Takahide Fukuyama,
• Tomohiro Nakagawa,
• Shinji Taguchi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2022, 18, 152–158, doi:10.3762/bjoc.18.16

• Research & Development Group, Nankai Chemical Co. Ltd., 1-1-38 Kozaika, Wakayama 641-0007, Japan Department of Applied Chemistry, National Yang Ming Chiao Tung University (NYCU), Hsinchu 30010, Taiwan 10.3762/bjoc.18.16 Abstract We report the high-speed C–H chlorination of ethylene carbonate, which gives

• ethylene carbonate was introduced to the reactor, the residence time was measured to be 15 or 30 s, depending on the slope of the reactor set at 15 or 5°, respectively. Such short time of exposition sufficed the photo C–H chlorination. The partial irradiation of the flow channels also sufficed for the C–H

• of ethylene carbonate such as 61%, the selectivity for monochlorinated ethylene carbonate over dichlorinated ethylene carbonate was 86%. We found that the substrate contamination with water negatively influenced the performance of the C–H chlorination. Keywords: C–H chlorination; chlorine gas

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• -catalyzed norbornene-mediated C–H activation [35] failed and gave 1,4-bis(2-bromophenyl)piperazine-2,5-dione (22, Scheme 5) as the sole product in 61% yield, which to our knowledge is not documented in the literature yet. Synthetic pathway (c) started from methyl 4-(2-nitrophenyl)-3-oxobutanoate prepared in

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

• Soumyadip Basu,
• Sauvik Chatterjee,
• Suman Ray,
• Suvendu Maity,
• Prasanta Ghosh,
• Asim Bhaumik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

•  1a). The spectroscopic FTIR study revealed the interaction between the metal and the NH2 and OH groups of chitosan. In both spectra, the peaks around 1100, 1400, 1600, and 2900 cm−1 corresponded to the C–O, C–N, and N–H (bending) as well as to the C–H bonds of the chitosan moiety, respectively. The

Earth-abundant 3d transition metals on the rise in catalysis

• Nikolaos Kaplaneris and
• Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

• , Germany 10.3762/bjoc.18.8 Keywords: C–H activation; 3d transition metals; green chemistry; late-stage functionalization; sustainability; Transition metal catalysis has emerged as a transformative platform for the assembly of increasingly complex compounds, with enabling applications to natural product

• witnessed major momentum in metal-catalyzed C–H activation [4][5] as a more resource-economical strategy. This approach involves the efficient and selective cleavage of otherwise inert, yet omnipresent C–H bonds. This strategy avoids a variety of steps and reduces the amount of chemical waste. Very recently

• . Applications of this strategy range from late-stage functionalization to modern photocatalysis and electrocatalysis, with contributions from around the globe, including Brazil, China, Japan, Germany, India, and South Korea, among others. The increasing use of C–H activations in academic and industrial

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• cyclic amines than the aerobic oxidation system. The catalytic cycle for the hydrogen peroxide system involves the formation of the oxoruthenium species (A) and the low-valent ruthenium species (B), whereas the aerobic oxidation system includes C–H activation and a subsequent reaction with molecular

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• 1% in proteins, but is highly conserved in binding sites on protein surfaces mediating PPI [43], it is an attractive target for the development of selective diversifications. C–H activation of the indole C2 position by Pd-catalysis allows both selective arylation [44][45][46][47][48] and formation

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• strategy for aldehyde C–H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the

• differences are discussed. Keywords: C–H functionalization; DABCO; HAT; photocatalysis; Introduction The functionalization of inert C–H bonds is a goal pursued by chemists from decades, due to its ubiquity in organic molecules. This strategy also dismisses tiresome protecting groups and functional group

• interchanging steps, often required in traditional synthetic methodologies [1][2]. The development of photocatalysis enabled inexpensive access to C–H activation methodologies under mild conditions, with hydrogen atom transfer (HAT) reactions standing out as a main strategy [1][3][4]. The hydrogen abstractor is

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

• significant development over the past 10 years. First achieved by Li and co-workers in 2007 [44], cross-dehydrogenative-coupling (CDC) reactions offer a highly atom economic approach to carbon–carbon (C–C) and carbon–heteroatom (C–X) bond formation via C–H activation [45][46]. Generally speaking, C–C bond

• forming reactions can be classified into three types (Scheme 1): the reaction of a compound bearing functional group (X), coupling with another compound bearing functional group (Y), producing a new C–C bond through the formation of X–Y (Scheme 1a). Secondly, the reaction of a C–H compound with a C–X

• functionalized compound (Scheme 1b). Lastly, the reaction between two C–H compounds to form a C–C bond, formally eliminating H2, hence the dehydrogenative reference (Scheme 1c). As this coupling reaction does not require functionalization prior to coupling, it shortens the synthetic route, and lowers the

Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol

• Lin Zhang,
• Jun Zheng,
• Guangyan Luo,
• Xiaoyue Li,
• Yunqian Zhang,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194

• superposition of the spectra recorded for Q[8] (a) and CPE (b), and there was no interaction. When comparing (c) and (d), the C–H stretching vibration peak was observed at 3100 cm−1 and the C=C skeleton vibration peaks of the benzene ring of CPE were observed at 1603, 1520 and 1413 cm−1; the bending vibration

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

• Chuanhua Qu,
• Run Huang,
• Yong Li,
• Tong Liu,
• Yuan Chen and
• Guiting Song

Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193

• sulfones is a valuable and appealing task in synthetic chemistry. Traditionally, diarylmethyl sulfones are synthesized by transition-metal-catalyzed deoxy C–S bond-coupling reaction of sodium arylsulfinates with diarylmethanols [11], C–H functionalization of alkyl sulfones with aryl halides [12], and via a

Me₃Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

• Krishna M. S. Adusumalli,
• Lakshmi N. S. Konidena,
• Hima B. Gandham,
• Krishnaiah Kumari,
• Krishna R. Valluru,
• Satya K. R. Nidasanametla,
• Venkateswara R. Battula and
• Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

• of isoquinoline N-oxides [41][42], condensation of lithiated o‐tolualdehyde tert‐butylimines with nitriles [43], electrophilic cyclization of 2-alkynylbenzamides [44][45] or 2-alkynylbenzaldoximes [46][47][48][49][50][51][52][53][54], oxidative C–H functionalizations (coupling) on aryl and heteroaryl

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• phosphoric acid-catalyzed synthesis of axially chiral compounds and to suggest that much more attention should be paid to these catalysts in order to promote asymmetric synthesis. Review 1. Enantioselective synthesis of atropisomeric biaryls Direct C–H functionalization strategies for the atroposelective

• aryl–aryl cross-coupling using various transition-metal catalysts has rarely been successful for the enantioselective construction of hindered biaryls [39] due to the discord between the temperature tolerance of the rotational axis and the high temperature required for C–H activation and suffered from

• be prepared by asymmetric C–H activation. The C–H activation or functionalization can be achieved by a metal-catalyzed chiral phosphoric acid ligand-assisted method, which offers distinct possibilities to provide various chiral biaryl compounds by changing different directing groups (DGs) [46]. Since

Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• and sustainable access to 2-functionalized tetrahydroisoquinolines. Keywords: continuous flow; copper; catalysis; dehydrogenative cross-coupling; electrochemistry; Introduction The dehydrogenative cross-coupling of two C–H bonds represents an ideal strategy for the construction of C–C bonds [1][2

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• original source). Tandem synthesis of functionalized α-amino cyclopentanones 119 from heteroarenes 115 and cyclobutanone-derived cyanohydrins 116. a) Pd-catalyzed C–H addition of 115 to the nitrile group of 116 produces intermediates 117 and 118. An α-iminol rearrangement with ring expansion subsequently

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• complexes to photocatalysis are reported. Copper-photocatalyzed reactions, including alkene and alkyne functionalization, organic halide functionalization, and alkyl C–H functionalization that have been reported over the past 5 years, are included. Keywords: copper-photocatalyzed reactions; green chemistry

• functionalization, organic halides functionalization, and alkyl C–H functionalization, are highlighted. Review 1. Special features of photoredox-catalyzed processes by copper complexes To understand photoredox-catalyzed processes, a discussion of the general mechanism of [Ru(bpy)3]2+ is needed [25][26][27]. When

• bonds and can be applied to radical chemistry. This review discusses copper-catalyzed reactions including alkene and alkyne, organic halide, and alkyl C–H functionalization. 3. Visible-light-mediated copper-catalyzed alkene and alkyne functionalization 3.1 Olefinic C–H functionalization and allylic

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• , indicating a strengthening of the carbon-oxygen bond. This is caused by a weakening of inter-perylene C–H–O interactions that also contribute to the stacking behavior [28][29], which in turn increases the electron density in the C=O bond. In addition to these shifts in band positions, all bands show

Copper-catalyzed monoselective C–H amination of ferrocenes with alkylamines

• Zhen-Sheng Jia,
• Qiang Yue,
• Ya Li,
• Xue-Tao Xu,
• Kun Zhang and
• Bing-Feng Shi

Beilstein J. Org. Chem. 2021, 17, 2488–2495, doi:10.3762/bjoc.17.165

• , Zhengzhou University, Zhengzhou, 450001, China School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, He’nan, 453007, China 10.3762/bjoc.17.165 Abstract A copper-catalyzed mono-selective C–H amination of ferrocenes assisted by 8-aminoquinoline is presented here. A range of amines

• the directing group could be removed easily under basic conditions. Keywords: amination; C–H activation; copper; ferrocene; mono-selectivity; Introduction Ferrocene-based compounds have broad applications from asymmetric catalysis to medicinal discovery [1][2][3][4][5][6][7][8]. Therefore, the

• ][10][11][12]. However, the above protocols generally proceeded under harsh conditions that led to poor functional group tolerance and generated stoichiometric amounts of waste. Thus far, the transition-metal-catalyzed C–H functionalization strategy has innovated the way to producing ferrocene

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• al. reported a Hg(II) chloride-mediated cyclization reaction of 2-alkynylphenyl alkyl sulfoxide 179 to synthesize benzothiophene derivatives 180 with good yields [114]. In this case, the reaction was believed to proceed via the initial formation of metal carbenoids followed by a sequential C–H

Halides as versatile anions in asymmetric anion-binding organocatalysis

• Lukas Schifferer,
• Martin Stinglhamer,
• Kirandeep Kaur and
• Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

• developed in the past decades, all based on polarized hydrogen bond motifs. While commonly based on N–H bonds [15][16][17][18], also polarized O–H [19][20] and even C–H [21][22] bond-based systems have been realized. As a consequence of the importance and increasing attention of this field, there are

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• Lusina Mantry Rajaram Maayuri Vikash Kumar Parthasarathy Gandeepan Department of Chemistry, Indian Institute of Technology Tirupati, Tirupati – Renigunta Road, Settipalli Post, Tirupati, Andhra Pradesh 517506, India 10.3762/bjoc.17.143 Abstract Catalytic C‒H functionalization has become a

• powerful strategy in organic synthesis due to the improved atom-, step- and resource economy in comparison with cross-coupling or classical organic functional group transformations. Despite the significant advances in the metal-catalyzed C‒H activations, recent developments in the field of

• metallaphotoredox catalysis enabled C‒H functionalizations with unique reaction pathways under mild reaction conditions. Given the relative earth-abundance and cost-effective nature, nickel catalysts for photoredox C‒H functionalization have received significant attention. In this review, we highlight the

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• direct C–H arylation strategy to obtain the polymers 81 and 83, respectively, in good yields (Scheme 17). Both polymers 81 and 83 were soluble in solvents such as chloroform and chlorobenzene and their Mn and PDI were found to be 22100 and 13500 Da, and 3.68 and 3.26, respectively. Their thermal

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• ]. The reason behind the C-2 attachment of the boron atom rather than at the C-3 position of the indole ring was explained by McGough et al. [37]. They performed a base-free catalytic I2-assisted indole C–H functionalization (electrophilic borylation) using the N-protected indole 1 and NHC·borane 4a that

• indolyl amines through Buchwald–Hartwig cross coupling. Synthesis of 3,3’-bis(indolyl) ethers. C–H silylation of indoles. n-BuLi-mediated syntheses of bis(indol-3-yl)silanes. Acid-catalyzed syntheses of bis(indol-3-yl)silanes and mechanisms. B(C6F5)3 and Al(C6F5)3-catalyzed syntheses of bis(indol-3-yl

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• demonstrate this surface modification using a hydrogel, poly(2-hydroxyethyl methacrylate) (PHEMA) [19]. However, this approach should have broad utility for a spectrum of monomers and macromonomers susceptible to radical polymerization onto (almost) any surface featuring C–H bonds. This hydrogel coating is

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• by treatment with PCC/Celite in dichloromethane (DCM). Finally, treatment with a catalytic amount of CF3SO3H provided the corresponding anthracenes 30a–c in good yields (57–75%) [40]. Metal-catalyzed C–H bond activation In 2016, Hong’s group developed a synthetic strategy to generate substituted

• anthracene derivatives 33. The strategy involved a palladium(II)-catalyzed tandem transformation with diphenyl carboxylic acids 31 and acrylates 32 (Scheme 7) [41]. This new methodology involved a carboxyl-directed C–H alkenylation, a carboxyl-directed secondary C–H activation, an intramolecular C–C-bond

• -workers reported a one-pot synthesis of substituted anthracenes 37 from o-tolualdehyde 34 and aryl iodides 35 via a palladium-catalyzed C–H arylation with a silver oxidant (Scheme 8) [42]. During optimization studies, the authors noted that steric and electronic effects strongly affected the cyclization