Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• photosynthesis research not only because they occur in biological photosynthesis but also because the PCET can circumvent unstable one electron-reduced intermediates. This makes PCET mechanisms well-suited for complex multielectron reactions required to transfer electrons and protons from water onto carbon

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• provides an overview of the reactions of iodonium ylides in which halogen bonding has been invoked. Herein, we summarize key discoveries and mechanistic proposals from the early iodonium ylide literature that invoked halogen bonding-type mechanisms, as well as recent reports of reactions between iodonium

• cyclopropane 22a. Interestingly, Hadjiarapoglou also revisited their investigation of iodonium ylide cycloadditions and their associated mechanisms [120], using diphenylketene as a new reaction partner with dimedone iodonium ylide 6 (analogous to earlier work reported by Koser in 1975 [9]). Investigations by

• , their scope has recently expanded to include X–H insertions based on single electron transfer (SET) mechanisms, cycloadditions based on blue LED photochemistry and radiofluorinations of unactivated arene motifs. In these reports, mechanistic proposals commonly treat the hypervalent iodine atom as being

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• intersystem crossing (rISC) is slow, without coupling with an approximate 3LE state. These studies are useful for an in-depth understanding of the photophysical mechanisms of the TADF emitters, as well as for molecular structure design of new electron donor–acceptor TADF emitters. Keywords: charge-transfer

• [38][39][40][41][42][43][44] and, more recently, time-resolved electron paramagnetic resonance (TREPR) spectroscopy [33][39][44][45][46] were also applied to study TADF mechanisms, but the examples are limited. Therefore, much room is left for studies of the photophysical mechanism of the TADF

• state energy), while keeping other factors intact to a large extent (e.g., the LE state energy). This is an important advantage for the study of complicated photophysical mechanisms involved in TADF processes. The syntheses of the dyads are based on the known derivatization chemistry of NI and PTZ

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• into the cell through membrane receptors and transporters. Eventually, the bound metal is released through reductive or hydrolytic mechanisms [2]. In the past years, β-proteobacteria have received increasing attention as producers of siderophores with interesting chemical features. For instance

• underlie discrete regulation mechanisms, which explains their context-dependent production [27]. The examples of P. aeruginosa and B. anthracis suggest that siderophore biosynthesis sometimes requires specific triggers beyond iron deficiency, which may not be met under laboratory conditions. The six

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• Photoresponsive rotaxane discrete crystals A complete understanding of the crystallization mechanisms accompanied by a rational design can lead to the obtention of crystalline molecular materials which allow the dynamics of the counterparts to take place [35][36][37]. Indeed, the motion of the cyclic counterparts

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• the mechanisms involved. Keywords: C–H functionalization; heterocycles; pyridine; rare earth metal; transition-metal-catalyzed; Introduction Pyridine, one of the most important azaheterocyclic scaffolds, is found in a diverse range of bioactive natural products, pharmaceuticals, and functional

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• of the methanol molecule occurs only for intermediate A and is not observed for product 11. It is important to emphasize that earlier, when discussing the mechanisms of the 6π-electrocyclization of various terarylenes accompanied by subsequent elimination of small molecules, we assumed a [1,9]-H

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• have developed a machine learning-augmented DFT method for computational NMR, DU8ML, for fast and ‘accurate’ computational approaches [2]. They applied this computational method to a number of previously published organic compounds and claimed to have revised some structures and proposed new mechanisms

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• propagate further. A subsequent migratory insertion into a second azaspirotricyclic alkene furnishes 183. Finally, the anion from the catalyst attacks 183 causing a ring opening, forming the final product 178d and regenerating the Rh(I) catalyst. Keeping with other mechanisms, the Rh(I) may also undergo an

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• amide derived from 8-aminoquinoline 13e (Scheme 6, 13 examples, up to 75% yield). In this study, two mechanisms were reported. The first one suggested that a palladacycle C is formed after the irreversible chelation of the 2-phenylpyridine substrate with palladium, which is the rate-determining step

Asymmetric synthesis of a stereopentade fragment toward latrunculins

• Benjamin Joyeux,
• Antoine Gamet,
• Nicolas Casaretto and
• Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32

• presence of DIPEA, performed well in the aldol reaction to furnish product 21 in 55% yield with a good dr of 91:9 (Scheme 3). The stereocontrol of the reaction could be envisaged through two principal mechanisms. A remote stereocontrol by the nucleophile could first be expected [29], through a 1,5-anti

Group 13 exchange and transborylation in catalysis

• Dominic R. Willcox and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

• ). Thomas and Gunanathan independently reported the borane-catalysed double hydroboration of nitriles using either Me2S·BH3 or H-B-9-BBN, respectively, as the catalyst and HBpin as the turnover reagent (Scheme 9) [72][73]. Both reports proposed similar mechanisms for the Me2S·BH3- and H-B-9-BBN-catalysed

• species 93, followed by Al‒O/B‒H exchange with HBpin to give the alkoxy boronic ester 94 and regenerate the aluminium hydride 92 (Scheme 23). Several aluminium hydride compounds have been reported as competent carbonyl hydroboration catalysts, with proposed mechanisms similar to Roesky’s initial report

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• ) The reprotonation of 1 at C-4 potentially leads to four stereoisomers of cation K, B) reprotonation at C-10 can result in four stereoisomers of L. The sesquiterpenes derived from cations K1, K2 and K4. A) Mechanisms of formation for compounds 53–56, B) pyrolysis of 58 to 53. The sesquiterpenes derived

• from cations L1–L4. A) Mechanisms of formation for compounds 54, 56, 59 and 60, B) dehydration of 61 to 56, C) oxidation of 56 to 62, D) dehydration of 63 to 60 and 64 (no yields were given in the original reports for the synthetic transformations shown in this Scheme).

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• mechanisms to help regulate/balance the populations of harmful species rather than eradicating them) based on the use of insect pheromones [2][3][4][5] is an eco-friendly solution for the protection of a wide range of crops and plants against pests. Indeed, those chemical mediators, which are emitted by

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• assessments of this topic [9]. Release kinetics study The in vitro release profiles of CPT-loaded amphiphilic cyclodextrin nanoparticles were fitted with a variety of kinetic models, and the release mechanisms, which are illuminating markers for novel drug delivery systems, were mathematically investigated

• two different colon tumors to differ from each other is the origin of the cells. The genome-transcriptome mapping investigation revealed that despite having two separate origins, the CT26 cell has characteristics similar to human primary colorectal cancers in terms of drug resistance mechanisms, gene

• discovered that inhibiting E-cadherins, which are adhesion molecules that provide intracellular connection, increases the sensitivity of 3D colon cancer tumors to 5-fluorouracil, paclitaxel, vinblastine, and etoposide [67]. In the literature, uptake mechanisms of nanoparticles and free drugs in 2D and 3D

Organophosphorus chemistry: from model to application

• György Keglevich

Beilstein J. Org. Chem. 2023, 19, 89–90, doi:10.3762/bjoc.19.8

• chemistry and beyond. Quantum chemical calculations are a great support for organic chemists when exploring structures, reactivities, and mechanisms. In this thematic issue, the Diels–Alder cycloaddition of 2-phosphaindolizine, 1-aza-2-phosphaindolizine, 3-aza-2-phosphaindolizine, and 1,3-diaza-2

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• generation of radicals from carbonyl reduction [18] but also manganese(III) acetate as a convenient one-electron oxidant [19]. The next twenty years, the field continued to flourish mainly by way of the decipherment of hydrogen atom transfer (HAT) mechanisms, which led to the establishment of several

Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B

• Adwoa P. Nartey,
• Aboagye K. Dofuor,
• Kofi B. A. Owusu,
• Anil S. Camas,
• Hai Deng,
• Marcel Jaspars and
• Kwaku Kyeremeh

Beilstein J. Org. Chem. 2022, 18, 1763–1771, doi:10.3762/bjoc.18.185

• ]. The major secondary metabolic pathways, defense mechanisms, and intracellular transport processes vary widely among Bacillus depending on their natural habitats [4][5][6]. Although the majority of Bacillus species are non-pathogenic, the few well-studied and genome-sequenced pathogenic strains among

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

• fundamentally different mechanisms have been proposed for the oxidation of alcohols [96] (Scheme 12). When using transition metals such as Cu(I) as co-catalyst, both aminoxyl radicals and metal ions serve as one-electron oxidants in a joint two-electron oxidation. In this system, primary aliphatic alcohols can

• processes [132][133][134]. Fluorinated substituents in the ketone molecule are used to achieve higher electrophilicity and reactivity. Both radical and ionic mechanisms were reported for CH-functionalization reactions [134][135]. An example of an oxidative hydroxylation involving aliphatic C(sp3)–H bonds is

• chiral copper complex. An extraordinary example of an asymmetric difluorination of alkenes with the migration of aryl or methyl groups was shown using a chiral aryl iodide catalyst [149][150] (Scheme 35). Depending on the nature of the migrating group, two mechanisms are possible that determine the

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• potent and significant drugs containing imidazole moieties. The formation of imidazole derivatives can be achieved using imidazole N-oxide as starting material. In this review, the scope of substrates and reaction mechanisms of various synthetic approaches using imidazole N-oxides as substrates are

• is a new emerging research area and which offers a lot of room for further development. In this review, several research procedures were discussed with their substrate scope and proposed reaction mechanisms. We hope that this review can be helpful to the researchers and the chemists for the future

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling

• Elenilson F. da Silva,
• Krist Helen Antunes Fernandes,
• Denise Diedrich,
• Jessica Gotardi,
• Marcia Silvana Freire Franco,
• Carlos Henrique Tomich de Paula da Silva,
• Ana Paula Duarte de Souza and
• Simone Cristina Baggio Gnoatto

Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161

• , Figure 1), is one of the few licensed drugs for treating RSV infections [8][9]. Although there are many suggested mechanisms of action, the main mechanisms for RBV involve the inhibition of the enzymes RNA-dependent RNA polymerase and inosine monophosphate dehydrogenase (IMPDH). IMPDH is required for the

• ). One of the main known mechanisms of action of RBV is the depletion of intracellular GTP pools via the inhibition of cellular IMPDH induced by the 5-monophosphate metabolite of RBV [44]. Thus, our finding based on these results is that compound 8 may act similarly to IMPDH inhibitors and the active

Molecular and macromolecular electrochemistry: synthesis, mechanism, and redox properties

• Shinsuke Inagi and
• Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 1505–1506, doi:10.3762/bjoc.18.158

• macromolecular electrochemistry. The scope of this interdisciplinary issue ranges from synthetic aspects (such as electrosynthesis and reaction mechanisms) to materials science (including redox properties and devices). Shinsuke Inagi and Mahito Atobe Yokohama, October 2022

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d₂)

• Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

• structure into first-generation non-nitrogen-containing BPs (non-NBPs) and into second- and third-generation nitrogen-containing BPs (NBPs). Some examples of NBPs are alendronate, risedronate, and zoledronate (Figure 1) [9]. NBPs and non-NBPs have different mechanisms of action, and NBPs have been shown to

Supramolecular approaches to mediate chemical reactivity

• Pablo Ballester,
• Qi-Qiang Wang and
• Carmine Gaeta

Beilstein J. Org. Chem. 2022, 18, 1463–1465, doi:10.3762/bjoc.18.152

• of the capsules by means of intermolecular interactions. The most intriguing aspect of catalysis in confined spaces [5][6][7][8][9][10][11][12][13][14] is that the reactions can take place through unusual mechanisms. This is mainly due to the conformational control of the substrates, steric