Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts

• Karen R. Winters and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154

• dual donor–acceptor role, such as P-stereogenic triflamide CPAs P(O)NHSO2CF3, is currently under investigation since BINOL-derived triflamides have been successful [48][49]. Another possibility would be to look at reactions in which the catalyst would not require a Brønsted basic site. Both directions

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• investigate the joint influence of the conformation flexibility and the matching of the energies of the charge-transfer (CT) and the localized triplet excited (3LE) states on the thermally activated delayed fluorescence (TADF) in electron donor–acceptor molecules, a series of compact electron donor–acceptor

• dyads and a triad were prepared, with naphthalimide (NI) as electron acceptor and phenothiazine (PTZ) as electron donor. The NI and PTZ moieties are either directly connected at the 3-position of NI and the N-position of the PTZ moiety via a C–N single bond, or they are linked through a phenyl group

• observed in the nanosecond transient absorption spectra with lifetimes in the 4–48 μs range. Computational investigations show that the orthogonal electron donor–acceptor molecular structure is beneficial for TADF. These calculations indicate small energetic difference between the 3LE and 3CT states, which

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• -illustrated by Hirshfeld surfaces [41] (Figure 3e and f). The guest molecule (water or methanol) acts as an H-bond acceptor with two axial NH units (distances N···O 2.85–2.93 Å, NHO 166.4–178.0°) and as an H-bond donor for the oxygen atom of the equatorial amide group (distances O···O 2.69–2.78 Å, OHO 163.7

Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes

• Almaz A. Zagidullin,
• Farida F. Akhmatkhanova,
• Mikhail N. Khrizanforov,
• Robert R. Fayzullin,
• Tatiana P. Gerasimova,
• Ilya A. Bezkishko and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139

• objects of growing interest in the fields of coordination chemistry [3][4][5] and asymmetric catalysis [6][7]. Due to the sp2-hybridization of the phosphorus atom, phosphaferrocenes are commonly regarded as phosphorus ligands with weaker σ-donor character than classical tertiary phosphines and stronger π

• -acceptor properties closer to phosphites P(OR)3 [8][9]. Since the P atom in phosphaferrocenes retains an electron lone pair, phosphaferrocenes have been used as P-donor ligands [10][11][12] as well as nucleophilic catalysts [13][14]. Recently, the pentaphosphaferrocene Cp*Fe(η5-P5) has been used as a

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• the non-doped device, at 2.0% demonstrated 100% exciton utilization efficiency in the device and efficient energy transfer from the host to the guest cyanine emitter. Deep blue emission in LEECs is challenging. We also reported a blue-emitting LEEC employing a cationic sulfone-based donor–acceptor

• tert-butylcarbazole as donor groups [24]. Pym-CZ showed red emission in dichloromethane (λPL = 691 nm, ΦPL = 43%) and in the neat film (λPL = 583 nm, ΦPL = 15%). The emission is further red-shifted and attenuated in Pym-tBuCZ in dichloromethane (λPL = 740 nm, ΦPL = 8%) and in the neat film (λPL = 593

• ). The presence of the DPA group in DiKTa-DPA-OBuIm transforms this compound from one that is MR-TADF to one that is better described as a donor–acceptor TADF, which is reflected in the red-shifted and broadened emission [28]. Results and Discussion DiKTa-OBuIm was obtained in three steps (Scheme 1) in

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• variety of biochemical, biophysical and computational methods [17][18][19][20][21]. Key for the oxidative chemistry performed by CYPs is a heme prosthetic group that activates molecular oxygen using electrons from an electron donor such as NADPH. A central Fe(III) ion is coordinated by the heme porphyrine

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• stable and inexpensive phosphate donor polyP [24]. Besides the difference among PPK families, further process parameters determine the kinetic preference towards ATP synthesis or utilisation. Especially for synthetic reactions with the aim to produce and isolate phosphorylated product, the initial

• (phosphoenolpyruvate as phosphate donor) is strongly favouring ATP synthesis both in vivo and in vitro, this reaction was originally considered to be irreversible in cells and a point of flux control. Newer findings showed the reaction to be actually an equilibrium, although positioned far on the product side [27][28

• ][29]. Also for carbamate kinase (using carbamoyl phosphate), the equilibrium lies far on the ATP side with a calculated equilibrium concentration of 3.9 × 10−4 M ADP out of 0.1 M ADP [30]. As most kinases use a phosphate donor with a high phosphate transfer potential (see Figure 3c) and a product

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• thermally activated delayed fluorescence (TADF) characteristics are emerging due to the potential applications in optoelectronic devices, time-resolved luminescence imaging, and solid-phase sensing. Herein, we synthesized two (4-bromobenzoyl)pyridine (BPy)-based donor–acceptor (D–A) compounds with varying

• donor size and strength: the emitter BPy-pTC with tert-butylcarbazole (TC) as the donor and BPy-p3C with bulky tricarbazole (3C) as the donor unit. Both BPy-pTC and BPy-p3C exhibited prominent emission with TADF properties in solution and in the solid phase. The stronger excited-state charge transfer

• was obtained for BPy-p3C due to the bulkier donor, leading to a more twisted D–A geometry than that of BPy-pTC. Hence, BPy-p3C exhibited aggregation-induced enhanced emission (AIEE) in a THF/water mixture. Interestingly, the singlet–triplet energy gap (ΔEST) was reduced for both compounds in the

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• ) coordination environment in the form of a Schiff base is considered as a route to electrochemical broadening of the donor–acceptor cyclopropane concept in combination with chirality induction in the targeted products. A tendency to the reductive ring-opening and the follow-up reaction paths of thus formed

• provides targeted pharmacophoric properties of the bio-active molecule [23] but also opens a route to its further functionalization, being a building block with wide variety of reactivity. A donor–acceptor cyclopropane concept suggested in the 1980s [24] became extremely popular in the recent decade [25

• ][26]. Donor–acceptor cyclopropanes constitute an easily available equivalent of all-carbon 1,3-zwitter-ions used in targeted synthesis of various alicyclic as well as carbo- or heterocyclic compounds [27][28][29][30]. The reactive synergy of the three-membered ring and the C–C bond polarization due to

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• possess antibacterial [2], antifungal [3], and antiviral properties [4] and form the core structure of commercially available drugs like brimonidine, varenicline, and quinacillin [5]. Quinoxalines can also be used in organic solar cell polymers [1][6] and have been described as donor moieties in many TADF

Facile and diastereoselective arylation of the privileged 1,4-dihydroisoquinolin-3(2H)-one scaffold

• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1070–1078, doi:10.3762/bjoc.18.109

• (Danheiser method [22]) or ethoxalylation [23]. Fortunately, all of the substrates 11a–s were converted cleanly and smoothly over 2–5 days into their diazo derivatives 10a–s using p-(acetamido)benzenesulfonyl azide (p-ABSA) as the diazo group donor [24] and DBU as the base. The yields of diazo compounds 10

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

• Koichi Mitsudo,
• Haruka Inoue,
• Yuta Niki,
• Eisuke Sato and
• Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

• . Compound 3a was obtained as a major product (26% yield) and 2a was obtained in 6% yield (Scheme 4a). Hydrogenation of the alkene moiety of 4a would proceed selectively, and 2a would be generated via a transfer hydrogenation reaction from 3a as a hydrogen donor [32][33][34][35]. These results suggest that

• . Interestingly, the generation of phenol was observed (7% yield), probably because 1a could serve as a hydrogen donor due to the low concentration of hydrogen [32]. Conclusion In conclusion, we have developed a system for the electroreduction of enones using a PEM reactor. The reactions proceeded under mild

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• ][16][17][18][19][20][21][22], as well as fluorescent probes [23][24][25][26][27][28] for bioimaging and fluorescent sensors for specific target species [29][30][31][32]. Among many kinds of organic fluorescent dyes, much efforts have been made on the development of donor–π–acceptor (D–π–A)-type

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• donor–acceptor interaction [21]. With this strategy, fusing those systems should lead to greater π-delocalisation [15][22]. Moreover, the fused core system is flanked by thiophene groups with ethylhexyl groups which impart solubility [5] in common organic solvents such as tetrahydrofuran, chloroform or

• with the donor polymer 13, PCEs up to 17% were achieved [8]. More recently, another fused-thiophene containing NFA was published, Y6 (14), shown in Figure 6 [30]. Y6 held the record for the highest value of an OPV with PCEs up to 18% upon blending with polymer 15 [31]. This has now been surpassed; in

• 2021, Hou et al. reported a ternary OPV, using a mixture of the novel PBQx-TF (16) donor polymer and the non-fullerene acceptor eC9-2Cl (17), shown in Figure 7. In addition, a third material, F-BTA3 (18) was blended in [32]; all three materials are fused thiophene systems. The resulting OPV achieved a

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• ]. Guo, Han and Ma et al. also performed the synthesis of aryl imidazopyridinyl selenides in the presence of Ag2CO3 (2 equiv) and Cs2CO3 (2 equiv) using the CuI/1,10-phenanthroline catalytic system by replacing the aryl group donor with arylboronic acids [23]. Zhou et al. reported the reaction of Se

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• such as CDCl3, resonance broadening may also be due to intermolecular association. The chemical shift of donor protons (D–H) involved in intermolecular hydrogen bonds is generally very sensitive to concentration change. A variable concentration 1H NMR study of monomer A and trimer 3 was carried out in

• geometry by the N-methylamino side chain, the presence of a hydrogen bond NH donor group is a key element in controlling the main-chain conformation and side chains orientation. It should be noted that to date, the presence of D–H donor groups on the side chains has been little exploited to control the

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• multiple molecules [13]. The exciplex contains new excited states through charge transfer between a donor molecule and an acceptor molecule. This provides a simple way to create new luminescence processes through the intermolecular interactions of existing molecules [14]. It has been reported that new

• highly depends on the molecular design and structures, including linkers, donor and acceptor units, which requires complex and time-consuming molecular synthesis and optimization [21][22][23]. In contrast, the introduction of specific Lewis acid–base pairs in existing molecules can be utilized to achieve

• brand new luminescent properties. In this mini-review, we summarize unique electron donor and acceptor materials which regulate luminescent properties via Lewis acid–base interactions and briefly explain the exploration of their chemical nature and interaction mechanisms. Review Lewis acids as electron

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• smegmatis (Scheme 4) [32]. A solution of the acyl donor 12 in ethyl acetate and an aqueous buffer solution of the corresponding alcohols 11 are mixed in a T-piece and the resulting segmented flow is pumped through a packed-bed reactor containing the immobilized transferase. The reaction mixture is directly

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

• azobenzenes in MeCN [52], we investigated how substituents of different donor strength affect the selectivity, reactivity, and reaction pathways of halogenation of azobenzene substrates under mechanochemical conditions. Halogenation of azobenzenes with strong electron-donating substituents In contrast to the

• substituents, the analogous reaction of L2 is slower because the methoxy substituent has weaker donor strength than amino substituents [57]. The protocols described above provide a solvent- and additive-free approach without added PdII catalysts for the halogenation of Csp2–H and imidation of Csp3–H bonds of

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• , respectively, was carried out with 5 via social self-sorting to form the Pd7 molecular cage 8 (Figure 2) as driven by the directionality of the donor nitrogen of the building ligands. The unique three-component Pd7 molecular boat has a proper internal nanocavity showing preferential affinity towards aromatic

• tetraphenylethene (TPE) units which act as an aggregation-induced emissive (AIE) fluorophore [65]. The newly designed TPE-based tetraimidazole donor 19 has been treated with 180°/120° trans-Pt(II) acceptors which led to the coordination-driven self-assembly of 3D discrete molecular cages in aqueous medium (Figure 5

• (26) was chosen as a FRET acceptor as there is a considerable overlap in energy of the donor emission and acceptor absorption. Then, artificial LHSs were constructed with aggregates from 24b or 25b at a donor/acceptor ratio of 5:1 (Figure 6). Finally, the light harvesting materials (24b + 26) and (25b

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• photophysically and computationally. The photophysical studies revealed that all the synthesized compounds exhibited fluorescence in organic solvents, while N-methyl-4-((pyridin-2-yl)amino)-substituted maleimide derivatives 4a–e, which are based on an acceptor–donor–acceptor (A–D–A) system, exhibited aggregation

• the electronic nature of the compounds with and without AIEE properties. Keywords: acceptor–donor–acceptor; AIEE; low molecular weight; one-pot reaction; ((pyridin-2-yl)amino)maleimide; TD-DFT calculation; Introduction Fluorescent compounds have attracted considerable attention as functional

• aminopyridines based on the acceptor–donor–acceptor (A–D–A) system exhibit AIEE properties in aqueous media, which may be novel candidate molecules for AIEE. Herein, we report the synthesis, photophysical properties, and computational studies of pyrido[1,2-a]pyrrolo[3,4-d]pyrimidines and N-methyl-4-((pyridin-2

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• DAS component 1 on the outcome of the Rh(II)-catalyzed decomposition. The results obtained clearly demonstrate that the nature of the substituent at the nitrogen atom in the DAS molecule has a minor effect: the substrates bearing both donor- and acceptor-substituted aryl groups form dimers 2 in high

• impurities. In one case, azine 4k was isolated in pure form and characterized. It should be noted that such azines are typically observed as byproducts in Rh(II)-catalyzed reactions of diazocarbonyl compounds [11][12][13][14]. The introduction of a strong donor substituent (MeO) in position 4 of the

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• ; Introduction The first reports on highly efficient thermally activated delayed fluorescence (TADF) mechanism and its successful realization in organic light emitting diodes (OLEDs) by Adachi and co-workers [1][2] have drawn the attention to the design and synthesis of various emissive donor–acceptor organic

• main requirement for efficient TADF is a negligible energy difference between the lowest singlet and triplet states (∆EST) which is often obtained in (hetero)aromatic compounds possessing twisted electron-donor (D) and acceptor (A) fragments with strong intramolecular charge transfer (ICT) [5][6][7

• ][19][20][21][22][23], and OLEDs [3][7][8][9][24]. In case of TADF emitters, a pyrimidine ring is often connected with a donor unit through a phenylene group as a conjugate π-spacer (s) [25][26][27][28]. As the majority of research describes TADF compounds with D-s–A–s–D layout, reports on TADF

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• derivatives were synthesized on the basis of Michael acceptor ability of 3-alkylidene oxindoles with various donor synthons [16][17][18][19][20][21][22]. However, in spite of the progress in the synthesis of dispirocyclopentanebisoxindoles with concise structural and stereochemical diversity, the one-pot

• mechanism is shown in Scheme 4. At first, tosylhydrazine as hydride source [29] promotes reduction of 3-phenacylideneoxindole towards 3-phenacylindolinone A. Then, under basic conditions, the carbanion of 3-phenacylindolinone, which acts as Michael donor, is formed. After this the carbanion undergoes

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• ) compound based on a donor–acceptor (D–A) architecture (D = phenoxazine; A = dibenzo[a,j]phenazine) has been developed, and its photophysical properties were characterized. The D–A compound is applicable as an emitting material for efficient organic light-emitting diodes (OLEDs), and its external quantum

• efficiency (EQE) exceeds the theoretical maximum of those with prompt fluorescent emitters. Most importantly, comparative study of the D–A molecule and its D–A–D counterpart from the viewpoints of the experiments and theoretical calculations revealed the effect of the number of the electron donor on the

• thermally activated delayed fluorescent behavior. Keywords: charge-transfer; dibenzophenazine; donor–acceptor; organic light-emitting diodes; thermally activated delayed fluorescence; Introduction Thermally activated delayed fluorescence (TADF), which was firstly reported in 1961 by Parker and Hatchard [1