Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• research. Keywords: light-mediated synthesis; mechanochemistry; photomechanochemistry; Introduction Light-mediated synthetic methodologies have significantly transformed contemporary organic chemistry by enabling a broad array of previously unattainable transformations [1]. In fact, the absorption of a

• solvent. Mechanochemical synthesis, particularly through ball milling, has emerged as a powerful and sustainable technique that offers numerous advantages over traditional solution-phase methods [40][41][42]. By often eliminating the need for solvents, mechanochemistry reduces environmental impact and

• mechanochemistry holds potential for unique opportunities for substrate activation while adopting an environmentally benign emerging technology (Figure 2, top). For example, it is well known that molecules in the solid state (or in very high concentration) often exhibit photophysical behaviors distinct from those

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• ; mechanochemistry; Introduction In recent years, mechanochemical organic synthesis has been advanced significantly, prompting organic chemists to reconsider the necessity of solvents in their reactions [1][2][3][4][5][6][7][8][9][10][11]. Eliminating hazardous solvents substantially reduces the ecological

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• nucleophiles in this transformation. Keywords: asymmetric catalysis; iminium catalysis; mechanochemistry; organocatalysis; thioesters; Introduction Mechanochemistry, particularly solventless processes under ball milling conditions, offers the opportunity to devise unconventional reaction pathways [1][2][3][4

• ][7][8]. Furthermore, the integration of mechanochemistry and organocatalysis leads to the development of more sustainable transformations, characterized by reduced reaction times, decreased catalyst loadings, and significantly diminished solvent usage and waste production [9][10][11]. The pioneering

• this research gap by introducing an effective methodology for generating enantiomerically enriched products, thereby expanding the scope of applications and contributing to a deeper understanding of stereoselective covalent catalysis, particularly in the field of mechanochemistry. Results and

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• their place among the efficient and robust catalysts on numerous occasions since the two seminal works [1][2] published in 2000. Since then, organocatalysis has been combined with many other areas of research, such as photocatalysis, electrochemistry and mechanochemistry [3][4][5], while List and

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• chemical synthesis [1][2]. Within this period, the Beilstein Journal of Organic Chemistry has organized two Thematic Issues (i.e., Mechanochemistry and Mechanochemistry II) to facilitate the open dissemination of the best research in the field of synthetic organic mechanochemistry. The great success of

• these past initiatives encouraged us to organize Mechanochemistry III, a new Thematic Issue in which the readership of the journal will find a collection of full research papers, letters and, for the first time, a Perspective article. In more detail, the readers will find new mechanochemical protocols

• (Scheme 1b). Similarly, in the absence of metal catalysts, N-fluorobenzenesulfonimide (NFSI) was found to act as a mild fluorinating reagent for activated aromatics by mechanochemistry [5]. Such a collective effort to access halogenated substrates is understandable, owning the synthetic value of organic

Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• ; mechanochemistry; phenolic KR; Introduction In the past decade, more than twenty chiral small molecule drugs were approved by the FDA, including ruxolitinib, afatinib, sonidegib, encorafenib, lorlatinib, darolutamide, alpelisib, artesunate, maribavir, ponesimod, daridorexant and others [1][2][3]. The

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• (mechanochemistry) can be accomplished through various experimental strategies. Among them, ultrasonication of polymeric matrices and ball milling of reaction partners have become the two leading approaches to carry out polymer and small molecule mechanochemistry, respectively. Often, the methodological differences

• between these practical strategies seem to have created two seemingly distinct lines of thought within the field of mechanochemistry. However, in this Perspective article, the reader will encounter a series of studies in which some aspects believed to be inherently related to either polymer or small

• molecule mechanochemistry sometimes overlap, evidencing the connection between both approaches. Keywords: ball milling; mechanochemistry; mechanophore; polymer; pulsed ultrasonication; Introduction In the past two decades, the growth in popularity of mechanochemistry has been unmistakable. During this

From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• mechanochemical conditions are presented. The two methodologies exhibit complementary features as they enable the derivatization of aliphatic and aromatic amines. Keywords: acetamides; formamides; mechanochemistry; N-formylation; p-tosylimidazole; Introduction The preparation of N-formylated and N-acetylated

• substantial excess of formyl or acyl sources, often used as a solvent. Mechanochemistry has been established as a powerful tool for the rapid, clean, and environmentally friendly synthesis of organic compounds, avoiding bulk solvent and restrictions of solvent-based chemistry [27][28][29][30][31][32][33][34

• ]. In general, mechanochemistry refers to studying solid-state chemical changes promoted by external mechanical energy, such as grinding or milling. A deeper understanding of its mechanistic aspects laid the basis for further growth in this topic, opening new routes to more efficient mechanochemical

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• -PCN300) show a reduction in photoluminescent recombination, as well as a nearly two-time increase in photocurrent under broad spectrum irradiation, which are appealing properties for photocatalysis. Keywords: carbon nitride; density functional theory; mechanochemistry; phosphorus; photochemistry

• , examples of carbon nitride materials linked together via phosphorus atoms are limited, likely due to challenges in controlling the insertion of phosphorus atoms as linkers under high energy conditions. Mechanochemistry [9][10][11][12] has proven to be effective for the synthesis of a variety of polymers

• explored herein the use of solvent-free, room temperature mechanochemistry to access phosphorus-linked carbon nitride with repeating heptazine units, which were found to show improved photochemistry over pristine graphitic carbon nitride (g-CN). Additionally, the effect of a 1-hour annealing period at 300

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

• Dharmendra Das,
• Akhil A. Bhosle,
• Amrita Chatterjee and
• Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

• reaction time, and mild reaction conditions are a few noticeable merits of this environmentally sustainable mechanochemical protocol. Keywords: automated grinding; chemoselectivity; mechanochemistry; N-bromosuccinimide; PEG-400; regioselectivity; stoichiometry-controlled halogenation; Introduction Aryl

• reactivity and availability of multiple sites for substitution, often leads to an inseparable mixture of halogenated products [27][28]. Thus, a cheaper and sustainable method for a regioselective halogenation in a controlled manner is a worthy pursuit. In recent times, mechanochemistry [45][46], achieved by

• of mechanochemistry, Toda et al.’s “grindstone chemistry” [48] has also been proved as a useful technique for various organic transformations [49]. It is generally carried out by hand-grinding which is not only a labor-intensive process but also raises some concerns on the reaction kinetics

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry

• Koji Kubota,
• Emiru Baba,
• Tamae Seo,
• Tatsuo Ishiyama and
• Hajime Ito

Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86

• mill; borylation; cross-coupling; mechanochemistry; solid-state reaction; Introduction Arylboronic acid and its derivatives are indispensable reagents in modern synthetic chemistry because they have been frequently used for the preparation of many bioactive molecules, natural products, and functional

• substrates for the synthesis of new arylboronates that are difficult to prepare by other means is currently under investigation. Development of the first solid-state palladium-catalyzed borylation protocol of aryl halides using mechanochemistry. Substrate scope of solid aryl bromides. Reaction conditions: a

Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides

• Petar Štrbac and
• Davor Margetić

Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75

• ; cycloaddition; debromination; Diels−Alder reaction; mechanochemistry; Introduction The complementarity of reaction conditions [1][2][3] where the reaction takes place under some, but not under other conditions, or where a chemical reaction proceeds in a different way or mechanism is a useful feature in

• synthetic organic chemistry. Advantageously, more difficult substrates or limitations of the conditions can be overcome by the change of the reaction methods. One of the emerging synthetic methods is mechanochemistry [4][5][6][7], a greener alternative to carry out synthesis which complements heating

A trustworthy mechanochemical route to isocyanides

• Francesco Basoccu,
• Federico Cuccu,
• Federico Casti,
• Rita Mocci,
• Claudia Fattuoni and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 732–737, doi:10.3762/bjoc.18.73

• straightforward procedure. Keywords: green chemistry; isocyanide; isonitriles; mechanochemistry; Introduction Isocyanides were first discovered more than a century ago by Lieke in Göttingen after having handled allyl iodide and potassium cyanide to synthesize crotonic acid. This attempt, instead, brought to the

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• reaction dynamics and characterization of the products was achieved by in situ Raman and ex situ NMR spectroscopy and PXRD analysis. A strong influence of the different 4,4’-substituents of azobenzene on the halogenation time and mechanism was found. Keywords: azo compounds; halogenation; mechanochemistry

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• . Keywords: ball mill; 1H-benzo[d]imidazole; C(sp2)–H amidation; DDQ; mechanochemistry; quinazolin-4(3H)-one; Introduction The reawakening approaches to use solvent-free and environmentally benign conditions in organic synthesis have facilitated new opportunities [1][2][3][4]. The research area of

• mechanochemistry [5][6] mainly focuses on conducting synthetic transformations in solid-state or solvent-free conditions. Mechanochemistry is one of the emerging avenues in chemistry that can make the world more sustainable by following the “Twelve Principles of Green Chemistry” [2]. Mechanochemistry is one of the

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• techniques, in this work we studied the reactivity of N-fluorobenzenesulfonimide (NFSI) by ball milling. We corroborated that, by mechanochemistry, NFSI can engage in a variety of reactions such as fluorinations, fluorodemethylations, sulfonylations, and amidations. In comparison to the protocols reported in

• solution, the mechanochemical reactions were accomplished in the absence of solvents, in short reaction times, and in yields comparable to or higher than their solvent-based counterparts. Keywords: amidation; ball mill; fluorination; in situ monitoring; mechanochemistry; NFSI; Raman monitoring

• reagent [9][10][11], and phenylsulfonyl group transfer reagent [12][13]. In the field of mechanochemistry, the usefulness of N-fluorobenzenesulfonimide has been exemplified in the asymmetric fluorination of β-keto esters (Scheme 1a) [14], and in diastereoselective fluorinations (Scheme 1b) [15], which

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• organocatalysis can benefit and accommodate many sustainability techniques [29]. Mechanochemistry can increase the sustainability profile of a chemical process by reducing potentially harmful organic solvents and bring other benefits such as substantially shortened reaction times. A handful of asymmetric

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

• , Poland 10.3762/bjoc.16.188 Abstract Mechanochemistry is an emerging and reliable alternative to conventional solution (batch) synthesis of complex molecules under green and solvent-free conditions. In this regard, we report here on the conjugation of a dextran polysaccharide with a fluorescent probe, a

• biocompatibility while remaining fluorescent. Keywords: ball milling; boronic ester; dextran; bodipy; nanoparticles; Introduction In the last few decades, mechanochemistry has gathered a great deal of attention and a lot of efforts have been focused on its use in organic synthesis, catalysis, biotransformation

• -free conditions, e.g., liquid-assisted grinding (LAG), slurries, and homogenous solutions. Although there are compounds that can only be achieved by conventional solution-based methods, mechanochemistry offers some important advantages over conventional bulk synthesis. These advantages have become more

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• aprotic liquids (e.g., N,N-dimethylformamide or dimethyl sulfoxide), which affect the final result, especially for potential biomedical applications. This article describes a new, green synthetic pathway through mechanochemistry, in particular via ball milling and using 1,1-carbonyldiimidazole as the

• , and rhodamine B) and the still reactive imidazoyl carbonyl group of the NS. Keywords: β-cyclodextrin; ball-milling; crosslinking; green chemistry; mechanochemistry; nanosponges; Introduction The research in the fields of nanomedicine and nanotechnology has nowadays become predominant

• derivatives and are biodegradable, so they are a very promising material from this point of view. In this article a new, green synthesis of nanosponges through a mechanochemical approach is proposed. Mechanochemistry relies on the application of mechanical forces (such as compression, shear, or friction) to

Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex

• Ross F. Koby,
• Nicholas R. Rightmire,
• Nathan D. Schley,
• Timothy P. Hanusa and
• William W. Brennessel

Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181

• ]∞, enable an otherwise unfavorable halide metathesis to proceed with mechanochemical assistance. From this result, we demonstrate that ball milling and unexpected solid-state effects can permit seemingly unfavored reactions to occur. Keywords: caesium; entropy; intermolecular forces; mechanochemistry

• between M'X and MX becomes particularly small? Here we describe the application of mechanochemistry in an organometallic context to examine alkali metal halide exchange unassisted by solvents. The organic group used is the bulky 1,3-bis(trimethylsilyl)allyl anion, [1,3-(SiMe3)2C3H3]− ([A']−) [13][14], for

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• a mechanochemical process. Keywords: AZADO; Ertalyte®; green chemistry; mechanochemistry; NaOCl·5H2O; selective oxidation; TEMPO; Introduction The conversion of primary and secondary alcohols to the corresponding carbonyl compounds (aldehydes and ketones, respectively) is of such importance in

• , especially in redox processes conducted in no-metal reactors, could prevent excessive heating of the jar, avoid the decomposition of starting materials and therefore, limit the formation of byproducts [40]. Following our interest in mechanochemistry and the design of new cost-effective oxidation procedures

• the previously described shortcomings. As of 2013, this reagent is commercially available [63], inexpensive and sufficiently stable and safe for potential applications in mechanochemistry (Figure S1a, Supporting Information File 1) [64][65][66][67]. Once the most promising oxidant was identified

Mechanochemistry II

• José G. Hernández

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

• Jose G. Hernandez Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany 10.3762/bjoc.15.154 Keywords: green chemistry; mechanochemistry; methods; organic chemistry; Since the publication of the first thematic issue on mechanochemistry in the Beilstein

• 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

• strategy for the future of chemical synthesis. In fact, the potential of mechanochemistry in various domains of research, industry and in commercial entities has been recently recognized by the IUPAC after the inclusion of mechanochemistry among the ten chemical innovations that will change our world [2

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• have different complexation properties to those of their classically prepared analogues. Keywords: crosslinked cyclodextrin polymers; (2-hydroxy)propylcyclodextrin; mechanochemistry; nucleophile reaction; planetary ball mill; solventless synthesis; Introduction The derivatisation of natural

• factors, but also by the lack of uniformity and the site-by-site variability of prepared CDPs, which have hampered the extensive CDP use. Mechanochemistry has proven to be a useful green tool in the hands of synthetic chemists [25][26][27][28]. The reaction of epoxides with cyclodextrins under green and

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• studied by in situ Raman and ex situ IR spectroscopy. Keywords: ball milling; Friedel–Crafts reaction; mechanochemistry; Introduction The Friedel–Crafts reaction (FCR) is a very powerful tool in organic chemistry for the synthesis of aromatic ketones. It is of great industrial importance and widely used

Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions

• Ana M. Belenguer,
• Adam A. L. Michalchuk,
• Giulio I. Lampronti and
• Jeremy K. M. Sanders

Beilstein J. Org. Chem. 2019, 15, 1226–1235, doi:10.3762/bjoc.15.120

• grinding; grinding frequency; kinetics; mechanism; mechanochemistry; Introduction We describe here an unusual frequency-dependence in the induction period of a covalent reaction carried out using ball-mill grinding. We present a kinetic analysis indicating that this is due to the successive fracture of

• crystals into smaller particles followed by the accumulation of energy in crystal defects. In recent years, manual and ball-mill grinding have become increasingly routine solid-state synthesis tools [1]. Generally referred to as mechanochemistry, these methods are more environmentally friendly and usually

• induce covalent bond formation, conducted by mechanochemistry [46]. A large induction period can be explained by two mechanisms: (1) time required for mass transport (mixing), or (2) time required for the accumulation of energy. While mass transport surely plays some role in the observed induction period