A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• , high yield, the use of dimethyl carbonate as a sustainable solvent, the use of an efficient alternative source of carbon monoxide, and avoiding a pressurized cylinder are some benefits of this protocol (Scheme 35) [59]. A feasible mechanism is illustrated for the synthesis of 1,2,3-triazole-5

Copper-mediated oxidative C−H/N−H activations with alkynes by removable hydrazides

• Feng Xiong,
• Bo Li,
• Chenrui Yang,
• Liang Zou,
• Wenbo Ma,
• Linghui Gu,
• Ruhuai Mei and
• Lutz Ackermann

Beilstein J. Org. Chem. 2021, 17, 1591–1599, doi:10.3762/bjoc.17.113

• Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany 10.3762/bjoc.17.113 Abstract The efficient copper-mediated oxidative C–H alkynylation of benzhydrazides was accomplished with terminal alkynes. Thus, a heteroaromatic removable N-2

• ] auxiliaries (Figure 1a). Besides, the cobalt(II)- [31] or nickel(II)-catalyzed [32][33], pyridine oxide (PyO)-directed tandem alkynylation/annulation was realized by Niu and Song et al., which also provided the 3-methyleneisoindolin-1-one scaffolds (Figure 1b). Notably, a sustainable cupraelectro-catalyzed

• -catalyzed C−H activations with the MHP auxiliary [41][42][43][44]. In continuation of studies on sustainable 3d transition metal-catalyzed C−H activation [41][42][43][44][45][46][47][48][49], we have now discovered a robust copper-promoted oxidative C−H/N−H functionalization with terminal alkynes (Figure 1d

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• -sustainable semiconductors are slowly being replaced by a new generation of semiconductors. Graphitic carbon nitride (g-CN) is a metal-free polymeric semiconductor that is mainly composed of carbon and nitrogen elements by tri-s-triazine, triazine imide, or heptazine repeating units [16][17][18]. g-CN

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• reaction mixture and reused several times, illustrating the practicability of this heterogeneous photocatalysis protocol. Further applying this sustainable and environmentally friendly CN-K heterogeneous photocatalyst to realize other synthetic useful transformations is undergoing. Evaluation of catalyst

Nitroalkene reduction in deep eutectic solvents promoted by BH₃NH₃

• Chiara Faverio,
• Monica Fiorenza Boselli,
• Patricia Camarero Gonzalez,
• Alessandra Puglisi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2021, 17, 1041–1047, doi:10.3762/bjoc.17.83

• safe as well as economically and environmentally sustainable alternative to the traditional organic solvents. Here, we report the combination of an atom-economic, very convenient and inexpensive reagent, such as BH3NH3, with bio-based eutectic mixtures as biorenewable solvents in the synthesis of

• derived from oil but from biorenewable resources, is a topic of primary importance in modern chemistry [1][2]. The solvents are the major contributor to the waste generated in chemical industries, and the elimination or replacement of these with more sustainable alternatives is part of the efforts of the

• whole research community concerned with the concept of a circular economy [3]. In this context, deep eutectic solvents (DESs) have attracted an increasing attention as green, safe, economically and environmentally sustainable alternative to the traditional organic solvents [4]. They are combinations of

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

• environment friendly sustainable technologies and procedures using atom-efficient reactions from suitable starting materials to meet the demands of present as well as future generations [1][2][3]. The need arises as the traditional method of synthesis has become unsustainable both from an environmental and

• majority of the atoms of the starting materials. The ability of forming multiple bonds in one-pot via a multicomponent reaction provides a novel and sustainable method in drug discovery [4]. In the recent years, these reactions have emerged as a promising strategy following green chemistry principles such

• their respective advantage over other synthetic protocols, merging strategy with technology proves to be an asset in organic synthesis. In view of the same, chemists worldwide have experimented with the combination which has proved to be highly efficient and sustainable. Over the past decade

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• electron transfer and forming a pair of radical ions trapped in the solvent cage. The pair of radical ions escapes the solvent cage by diffusion to give radical ions, which could initiate chemical reactions or reverse electron transfer (Scheme 1) [6]. The continuously increasing demand for sustainable

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• selective depolymerisation methods of plastics. Achievements are broken down according to the plastic material, namely polyolefins, polyesters, polycarbonates and polyamides. The focus is on recent advancements targeting sustainable and environmentally friendly processes. Biocatalytic or unselective

• processes, acid–base treatments as well as the production of fuels are not discussed, nor are the methods for the further upgrade of the depolymerisation products. Keywords: catalysis; depolymerisation; plastic; recycling; sustainable; Review 1. Introduction In a circular-economy perspective, wastes are

• kinetics, cost of metals, toxicity, difficulty in catalyst reusing and need of downstream processing. Significant efforts have thus been made to develop greener and sustainable catalytic systems featuring high efficiency under mild conditions. The use of sodium carbonate or bicarbonate as ecofriendly

Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols

• Marek Kõllo,
• Marje Kasari,
• Villu Kasari,
• Tõnis Pehk,
• Ivar Järving,
• Margus Lopp,
• Arvi Jõers and
• Tõnis Kanger

Beilstein J. Org. Chem. 2021, 17, 581–588, doi:10.3762/bjoc.17.52

• and the increasing importance of methods of sustainable chemistry have brought chemoenzymatic approaches for obtaining natural products, or derivatives thereof, with complex structure into focus [1]. Various enzymatic or semisynthetic methods have also been exploited in the synthesis of steroids [2][3

A sustainable strategy for the straightforward preparation of 2H-azirines and highly functionalized NH-aziridines from vinyl azides using a single solvent flow-batch approach

• Michael Andresini,
• Leonardo Degannaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2021, 17, 203–209, doi:10.3762/bjoc.17.20

• preparation of 2H-azirines and their stereoselective transformation into highly functionalized NH-aziridines, starting from vinyl azides and organolithium compounds. The protocol has been developed using cyclopentyl methyl ether (CPME) as an environmentally benign solvent, resulting into a sustainable, safe

• increasing effort towards the design of efficient production processes [1][2][3]. As a result, a number of sustainable synthetic strategies has been recently developed, lowering the environmental impact and reducing the chemical hazards associated with the preparation of highly valuable compounds [4]. Among

• risks [6]. Recently, a variety of sustainable solvents has been therefore identified, and their use have been combined with those of enabling technologies. In this scenario, the development of continuous flow synthetic methodologies has found its fortune in the past two decades [7][8][9]. Several

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

• to be developed [14]. The formation of new C–C bonds through direct C–H bond functionalization in organic chemistry is attractive [15]. Such methodologies are omnipresent and facilitate sustainable organic transformations for the synthesis of complex natural products and pharmaceuticals. In the past

Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates

• Hisham Qrareya,
• Lorenzo Meazza,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 3008–3014, doi:10.3762/bjoc.16.250

• metal-free eco-sustainable conditions we reinvestigated the photochemistry of di- and triaryl phosphates III and IV (Scheme 1e), compounds that can be easily achieved from the corresponding phenols [62][63]. Results and Discussion At the onset of our investigation, we tested a triaryl phosphate such as

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• Emine Kayahan Mathias Jacobs Leen Braeken Leen C.J. Thomassen Simon Kuhn Tom van Gerven M. Enis Leblebici Center for Industrial Process Technology, Department of Chemical Engineering, KU Leuven, Diepenbeek, Belgium Process Engineering for Sustainable Systems, Department of Chemical Engineering, KU

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• cellulose nanocrystals (CNCs), which are rod-like nanocrystallites liberated from lignocellulosic biomass under acid hydrolysis conditions [2]. A spectrum of applications have been investigated over the years for this sustainable bio-nanomaterial including drug delivery [3], food packaging [4

• ]. With shell waste being often discarded back into the sea or in landfills, it is imperative that downstream applications be developed such that environmental concerns and disposal costs for this neglected resource are reduced through the creation of bio-based sustainable technologies [13]. In this

• organic solvents (4:1 DMF/H2O) [26]. Conclusion ChNCs and ChsNCs were explored as sustainable supports for immobilizing Pd NPs to fabricate heterogeneous catalysts for the Heck coupling reaction. Through TEM and XPS analysis, metallic Pd NPs were formed and dispersed on the surface of the supports, while

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• ; sustainable chemistry; Introduction The words “sustainable” and “sustainability” are nowadays routinely used throughout common speech and the popular press, including published modern chemistry literature, when discussing topics related to pressing issues such as preservation of the environment, climate

• recent article published in Chemical and Engineering News in 2019 [1] nicely highlighted the problem in the context of distinguishing the terms green chemistry from sustainable chemistry. It was noted that “the term sustainable chemistry has been introduced more recently and possesses countless

• magnitude of SI will also have a value ranging between 0 and 1. This mathematical formalism conveniently allows the writing down of a quantitative definition of sustainability applicable to synthesis plans. A given synthesis plan can therefore be said to be completely “sustainable” if the following

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• evident with the development of atomized ball milling technologies, which allow for a better reproducibility and control of reaction parameters over traditional mortar or pestle [4][6]. Mechanochemical syntheses are not just a means for cleaner, safer, higher yielding, and more sustainable chemical

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• byproducts. It is inexpensive, sustainable (ideally not ruthenium or iridium complexes) and commercially available. Due to their comparatively high triplet energies and the long lifetime of their triplet states; organic dyes and various ruthenium and iridium complexes are well-suited photosensitizers [118

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

• Edgar Peris Raul Porcar Maria Macia Jesus Alcazar Eduardo Garcia-Verdugo Santiago V. Luis Dpt. of Inorganic and Organic Chemistry, Supramolecular and Sustainable Chemistry Group, University Jaume I, Avda Sos Baynat s/n, E-12071-Castellon, Spain Discovery Chemistry, Janssen Research and Development

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• °C) in the presence or absence of bases (Et3N). Keywords: deep eutectic solvents; imidazoles; phenacyl azides; phenacyl halides; pyrimidines; Introduction In a world with dwindling petroleum resources, the setting up of more and more sustainable routes for the preparation of heterocyclic compounds

• Sustainable Technologies Through Nature-inspired Solvents (NATUREChem) (grant number: 2017A5HXFC_002) financially supported by the University of Bari “A. Moro” (codes: SFARMA.RicercaLocale.Vitale Fondi Ateneo 17-18, PernaF.18 FondiAteneo15-16, VitaleP.18 FondiAteneo15-16), the University of Salento, the

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• Kumar Godugu Venkata Divya Sri Yadala Mohammad Khaja Mohinuddin Pinjari Trivikram Reddy Gundala Lakshmi Reddy Sanapareddy Chinna Gangi Reddy Nallagondu Department of Chemistry, Green and Sustainable Synthetic Organic Chemistry Laboratory, Yogi Vemana University, Kadapa-516 005, Andhra Pradesh

• ][2][3]. Among them, benzimidazoles, dihydropyrimidinones, and pyridines have emerged as promising and valuable structural units in many pharmaceutical lead compounds (Figure 1) [4][5][6][7][8][9]. Hence, there is a great need for the development of a green and sustainable synthetic route to the

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• Lucas Guillemard Joanna Wencel-Delord Laboratoire d’Innovation Moléculaire et Applications (UMR CNRS 7042), Université de Strasbourg/Université de Haute-Alsace, ECPM, 25 rue Becquerel, 67087, Strasbourg, France 10.3762/bjoc.16.147 Abstract While aiming at sustainable organic synthesis, over the

• ; sustainable synthesis; synergistic catalysis; Introduction In recent years, the field of synthetic chemistry has witnessed a profound evolution. Indeed, due to the growing environmental awareness, organic chemists face nowadays an urgent need of developing much more sustainable and environmentally benign

• complementary reactivities, the combination of these two activation modes could provide new solutions for sustainable organic synthesis. Indeed, new mutlicatalysis concepts have emerged recently and enabled the achievement of various yet unfeasible reactions [47]. Following this general goal, synergistic

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• catalysts is desirable for easy separation of the products. Thus, from a sustainable point of view, it is of interest to study heterogeneous catalysts for the direct conversion of cellulose or lignocellulosic biomass to isosorbide. Heterogeneous catalysts for the conversion of (ligno)cellulose to isosorbide

• first run was observed. A sustainable method for the isosorbide production from cellulose is the use of a bifunctional catalyst (Scheme 7). A series of Ru catalysts on acid support were prepared by the adsorption of colloidal Ru nanoparticles on mesoporous and bulk niobium phosphate, mesoporous and bulk

• . This study shows that a bifunctional catalyst can be a more sustainable solution to produce isosorbide from (ligno)cellulose. Conclusion The isosorbide synthesis from cellulose is performed via acid-catalyzed hydrolysis of cellulose, followed by hydrogenation of glucose to sorbitol and further

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• irradiation. Herein, we review some important developments of heterogeneous photocatalytic materials and their application in flow reactors for sustainable organic synthesis. Further, the application of continuous flow heterogeneous photocatalysis in environmental remediation is briefly discussed to present

• health. We conclude in Section 5 with a summary and our perspective on the future of HPCats in flow as a methodology for sustainable and scalable photosynthesis. 1.2 Importance of the review and brief historical perspective With growing socioeconomic and political pressure to act on anthropogenic

• emissions and subsequent environmental damage, much of the scientific community has shifted its focus to the development of sustainable methodologies, particularly in synthetic chemistry. The prospect of utilising light as a renewable source of energy to drive chemical reactions is an appealing solution to

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• : https://github.com/sustainable-processes/Pd-catalysed_C-H_activation_reaction_prediction. Results and Discussion Computational approach to rationalise reactivity in Pd-catalysed C–H bond activation reactions Chemical reactivity is simultaneously influenced by many factors including catalysts, reactants