Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• groundbreaking advancements were accomplished in this wonderful area of research, transforming a specific C–H bond effectively and selectively under favorable conditions (viz, room temperature, without external oxidant, cost-effective, sustainable, and environmentally friendly) still remains a highly challenging

• a more sustainable procedure [88] in comparison to previously reported methods [89][90][91][92]. These semiconductor photocatalysts were better because they were: (i) cheap, (ii) easily separable from the reaction mixture, (iii) compatible with other transition metals, and (iv) provided steady

Understanding the role of active site residues in CotB2 catalysis using a cluster model

• Keren Raz,
• Ronja Driller,
• Thomas Brück,
• Bernhard Loll and
• Dan T. Major

Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

• with numerous pharmacological [7][8] and biological activities have been reported, rendering them important targets for medical and biotechnology research [9]. Chemical synthetic and sustainable biosynthetic strategies in synergy with the biological activity of different terpene natural products have

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• Kesatebrhan Haile Asressu Cheng-Chung Wang Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan Taiwan International Graduate Program (TIGP), Sustainable Chemical Science and Technology (SCST), Academia Sinica, Taipei 115, Taiwan Department of Applied Chemistry, National Chiao Tung

A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones

• Daniel P. Pienaar,
• Kamogelo R. Butsi,
• Amanda L. Rousseau and
• Dean Brady

Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287

• catalytic amount of isopropanol, or 18-crown-6, was necessary to facilitate the reaction and to reduce side-product formation under ambient conditions. Keywords: acylation; β-ketonitrile; enolizable; trifunctionalized; sustainable; Introduction β-Ketonitriles represent highly versatile intermediates for

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• research efforts, there is no sustainable synthetic or biosynthetic approach to this molecule. More than half a dozen total syntheses, each requiring 37 steps [15][16] or more [14], have been reported, yielding at best 32 mg of the drug in toto, while the yearly pharmaceutical requirements are greater than

• , recombined, and reused easily for different applications. Insights into terpene biosynthesis, along with advancements in synthetic biology, will pave the way towards the sustainable and selective biotechnological production of high-value terpenes, such as taxol (1). One recent study describes the successful

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• potential greener and sustainable alternative to traditional redox protocols [1][2][3][4]. Starting from its inception in 1800, EOC has undergone a series of advances with respect to the design of electrochemical cells; the nature of the electrode materials; the applied current or potential; the available

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• Vania F. Pais Tristan Neumann Ignacio Vaya M. Consuelo Jimenez Abel Ros Uwe Pischel CIQSO – Centre for Research in Sustainable Chemistry and Department of Chemistry, University of Huelva, Campus de El Carmen s/n, 21071 Huelva, Spain Department of Chemistry/Institute of Chemical Technology UPV-CSIC

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• mutagenesis have exciting applications for the sustainable production of high value bioactive substances. Keywords: biotechnology; CotB2; crystal structure; cyclooctatin; diterpene; reaction mechanism; terpene synthase; Introduction Terpenes represent one of the most diverse groups of natural biomolecules

• subtilis of 9 µM and 10 µM for Micrococcus luteus, respectively [25]. For the sustainable, high yield production of bioactive diterpenoids various aspects have to be considered. One key issue in yielding high recombinant terpene production titers, are metabolic bottlenecks in the precursor supply, which

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• sustainable method for catalysis because sunlight is an essentially unlimited and thereby “green” natural light source and LEDs – conveniently used for irradiation experiments in the laboratory – are cheap and energy-saving artificial sources for irradiations. The current “working horse” for photoredox

Installation of -SO₂F groups onto primary amides

• Jing Liu,
• Shi-Meng Wang,
• Njud S. Alharbi and
• Hua-Li Qin

Beilstein J. Org. Chem. 2019, 15, 1907–1912, doi:10.3762/bjoc.15.186

• liver [23]. The nucleotide-derived probe 5’-(para-fluorosulfonylbenzoyl)adenosine (5’-FSBA) was used for labelling the second nucleotide binding site, the adenine nucleotide regulatory site [24]. In addition, aryl fluorosulfates have also been widely applied as sustainable alternative to aryl halides in

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

• ][60]. They have been employed for a number of organic reactions viz., hydrosilylation of aldehydes and ketones, acetylation reactions, redox reactions, oxidative esterification, etc. [61][62][63]. Thus, in concern with increasing demand for sustainable development, a growing number of catalytic

• the use of toxic reagents and solvents, harsh reaction conditions and long reaction times. The use of a heterogeneous catalyst and water made this method a green and sustainable approach for organic transformations. This transformation involved the well known three-component reaction of 3 with 1 and 2

• ethyl glycinate resulted in a 53% yield of the corresponding IP. The method was more atom economic and sustainable than others as it utilized air as a sole oxidant and generated water as the only byproduct. The reaction was carried out between pyridyl esters 102 and benzylamine (35) at 65 °C using

Mechanochemistry II

• José G. Hernández

Beilstein J. Org. Chem. 2019, 15, 1521–1522, doi:10.3762/bjoc.15.154

• Journal of Organic Chemistry in 2017 [1], the global interest in the field of mechanochemistry has continued exponentially growing. Thus, leading to the implementation of mechanochemical techniques across different areas of science. Such tremendous growth has established mechanochemistry as a sustainable

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• synthesis of diversely functionalized pyrroloacridinones in aqueous medium. A library of compounds was synthesized in a one-step pathway utilizing 10 mol % of the nanoreactor following a sustainable methodology in water with high yields. Keywords: heteroditopic macrocycle; organocatalyst; nanoreactor

• ; pyrroloacridinones; sustainable chemistry; water; Introduction Acridines are a renowned heterocyclic entity not only for their biological activities but also for their fluorescence and chemiluminescence properties. Acridine dyes (e.g., acridine orange, acridine yellow, etc.), are predominantly used in staining of

• , makes them highly valuable in view of sustainable chemical applications. Thus, the development of organocatalytic nanoreactors with new features is indeed important to address greener organic syntheses. On the other hand, the rational design of heterotopic macrocycles has attracted intense interest as

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• presents several other advantages besides atom economy, such as higher overall yields, easiness of procedure and work-up [12], less solvent being used, fewer residues being produced, fewer purification steps and time-saving, contributing to a more sustainable process (Scheme 1). The Strecker synthesis of α

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• the amides 47 (Figure 26). The development of sustainable methods for the activation of less-reactive undirected C(sp3)–H bonds is challenging however, highly desired in organic synthesis. Mal and co-workers also demonstrated that acidic C(sp3)–hydrogen bonds within a molecule could be used to control

A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12

• Seema V. Kanojia,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2019, 15, 490–496, doi:10.3762/bjoc.15.42

• can be executed under simple reaction conditions with commercially available and inexpensive materials/reagents. In this regard biocatalytic reactions offer green and sustainable alternative routes to develop asymmetric syntheses of pharmaceuticals with varied stereochemical features [30][31][32][33

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• tremendous impact in organic synthesis, enabling a variety of applications in polymer chemistry, drug discovery and chemical biology. Although challenging, the possibility to perform aqueous metatheses has become an attractive alternative, not only because water is a more sustainable medium, but also to

• performing catalysis in a more sustainable medium, it still remains challenging to achieve due to the detrimental effect of water. Despite this limitation, olefin metathesis widely contributes to polymer chemistry, drug discovery and biocatalysis. Several technologies relying on aqueous metathesis have been

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation

• Łukasz Gułajski,
• Andrzej Tracz,
• Katarzyna Urbaniak,
• Stefan J. Czarnocki,
• Michał Bieniek and
• Tomasz K. Olszewski

Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16

• interesting transformation. Furthermore, in the continuous search for new sustainable protocols for chemical reactions to induce new reactivates or reduce the energetic cost of the processes, the replacement of mechanical mixing and/or heating of the reacting species with microwave (μW) [46][47][48] and

Asymmetric synthesis of a high added value chiral amine using immobilized ω-transaminases

• Antonella Petri,
• Valeria Colonna and
• Oreste Piccolo

Beilstein J. Org. Chem. 2019, 15, 60–66, doi:10.3762/bjoc.15.6

• sustainable approach to an industrial scale. Keywords: asymmetric catalysis; biotransformations; chiral amine; immobilized enzymes; ω-transaminases; Introduction Enantiomerically pure amines are important precursors to biologically active compounds with different industrial applications, including

• more sustainable method for chiral amine production [2][3][4][5]. TAs, also known as aminotransferases, are enzymes capable of transferring an amino group from an amine donor to an acceptor containing a carbonyl functionality in the presence of pyridoxal-5'-phosphate (PLP) as a cofactor and the enzymes

N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

• Fabienne Speck,
• David Rombach and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5

• optoelectronic properties of the molecules. Photochemical methods have allowed to overcome some of the current limitations in thermally driven chemistry and to substitute conventional energy demanding chemistry by highly sustainable photochemical methods [3][4][5][6][7][8][9][10][11][12]. Phenothiazines have

Mn-mediated sequential three-component domino Knoevenagel/cyclization/Michael addition/oxidative cyclization reaction towards annulated imidazo[1,2-a]pyridines

• Olga A. Storozhenko,
• Alexey A. Festa,
• Delphine R. Bella Ndoutoume,
• Alexander V. Aksenov,
• Alexey V. Varlamov and
• Leonid G. Voskressensky

Beilstein J. Org. Chem. 2018, 14, 3078–3087, doi:10.3762/bjoc.14.287

• with three or more reactants mixed together, became a valuable tool for the synthetic chemistry to produce diverse and complex compounds in an efficient and sustainable way [14][15][16][17]. The use of oxidative conditions in MCRs was found to be useful [18], but challenging due to difficulty to match

The activity of indenylidene derivatives in olefin metathesis catalysts

• Maria Voccia,
• Steven P. Nolan,
• Luigi Cavallo and
• Albert Poater

Beilstein J. Org. Chem. 2018, 14, 2956–2963, doi:10.3762/bjoc.14.275

• Maria Voccia Steven P. Nolan Luigi Cavallo Albert Poater Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/ Mª Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain Department of Chemistry and Center for Sustainable Chemistry, Ghent University

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

• Jacqueline Pollini,
• Valentina Bragoni and
• Lukas J. Gooßen

Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252

• Jacqueline Pollini Valentina Bragoni Lukas J. Goossen Lehrstuhl für Organische Chemie I, Ruhr-Universität Bochum, ZEMOS, Universitätsstraße 150, 44801 Bochum, Germany 10.3762/bjoc.14.252 Abstract A convenient and sustainable three-step synthesis of the tyrosinase inhibitor 2-hydroxy-6

• subsequent hydrogenation step. Overall, the target compound was obtained in an overall yield of 61% based on the unsaturated anacardic acid content and 34% based on the crude CNSL. Keywords: cashew nutshell liquid; cross-metathesis; renewable feedstock; sustainable chemistry; tyrosinase inhibitor

• , undergoes smooth ethenolysis only in dichloromethane as the solvent (Scheme 3). Using more sustainable solvents or no solvent at all, the reaction gave almost no turnover, regardless of the ruthenium catalyst employed. However, as a 1.1 M solution in dichloromethane, the unsaturated components of CNSL were

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

• ligand. B12 is reduced to Co(I) species in the active center by reductases in sustainable processes. The partially π-conjugated system of the corrin ring is less easy to be adducted by free radicals than those of porphyrins. B12 is bound to a number of proteins and acts as a module. Different chemical

• catalysts. Despite extensive research, reproducing B12 enzyme reactions in vitro had been difficult in homogenous solutions. Construction of sustainable catalytic systems inspired by B12 enzymes is another important issue that must be addressed for green chemistry. Due to the above-mentioned unique redox

• principle. Chemical methods are considered as efficient techniques to directly degrade halogenated pollutants. Completely mimicking the complicated dehalorespiration systems requires tedious efforts. The concept of bioinspired chemistry would be an effective methodology to design sustainable systems. To

Catalyst-free synthesis of 4-acyl-NH-1,2,3-triazoles by water-mediated cycloaddition reactions of enaminones and tosyl azide

• Lu Yang,
• Yuwei Wu,
• Yiming Yang,
• Chengping Wen and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2018, 14, 2348–2353, doi:10.3762/bjoc.14.210

• , authentically mild conditions (40 °C stirring) as well as practical scalability. Keywords: additive-free; catalyst-free; cycloaddition; enaminones; on water; 1,2,3-triazole; Introduction Discovering sustainable chemical syntheses constitutes one central issue of modern organic chemistry. A large number of

• strategies and concepts promoting sustainable syntheses have been conceived over the past decades. Methods employing water as reaction medium are amongst the most promising ones by avoiding the application of volatile organic solvents during the reaction process [1][2][3]. Besides acting as a safer and

• , including those reactions involving valuable C–C [7][8][9][10][11], C–heteroatom [12][13][14][15][16], heteroatom–heteroatom [17][18] bond formation as well as divergent cascade reactions [19][20][21][22][23], are presently taking place to guide the progress of sustainable organic synthesis. 1,2,3-Triazole