Exploring the possibility of using fluorine-involved non-conjugated electron-withdrawing groups for thermally activated delayed fluorescence emitters by TD-DFT calculation

• Dongyang Chen and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 210–223, doi:10.3762/bjoc.17.21

• explore their potential computationally within TADF emitter design. We cross-compare their optoelectronic properties with analog materials using well-studied conjugated electron-withdrawing groups (cyano, benzophenone, and triazine). We investigated two families of structures. The first family consists of

• acceptors correlate linearly to the Hammett substituent constant, σp, (Figure 2c) [35]. All of these fluorinated acceptors are much weaker than the more commonly investigated benzonitrile (BN, −1.30 eV), triphenyltriazine (TRZ, −1.72 eV) and benzophenone (BP, −1.58 eV) acceptors. These results indicate that

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

• -benzophenone (DMBP) was studied. A single multisyringe pump was used to supply the reactants to the photomicroreactors. This kind of scaling up is called external numbering up since each reactor is fed directly by the pump. This numbering-up strategy allowed to run ten parallel microreactors at the same time

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• ] photocycloaddition of quinolone 170. The proposed mechanism proceeds via hydrogen-bonded complex 171, which is sensitised by the pendant benzophenone to its triplet excited state 171*. The following cycloaddition completes the cycle and generates the desired cyclobutane product 173 in excellent conversion but poor

• triplet excited state 182* (Scheme 27) [79][80]. However, the enantioselectivities for this reaction were poor (70:30 er), which prompted further catalyst design by changing the photosensitising group from benzophenone to xanthone 183 to improve enantioselectivity [79]. Xanthone has a higher triplet

• energy than benzophenone (3.2 eV vs 3.0 eV) and the authors attribute this difference to the increased efficiency; however, the efficiency of energy transfer is governed by spectral overlap between donor and acceptor. The much higher enantioselectivities observed (95:5 er) are attributed to a reduced

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

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

• [128]. These employ photosensitizers such as 9-fluorenone [127], 1,2,4,5-tetracyanobenzene (TCB) [129][130], 1,4-dicyanobenzene (CB) [126][131] and benzophenone [128] and proceed in low (23%) to excellent (96%) yields [126][128]. One of the most efficient and high-energy (79.4 kcal⋅mol−1) triplet

• −H monofluorination photosensitized by 9-fluorenone demonstrated a remarkable scope and reaction efficiency. A range of different photosensitizers (acetone, benzophenone, 9-fluorenone and Ir(ppy)3) were investigated. Acetone as a PSCat gave no product, likely due to its absorption bands (≈280 nm) well

• out of reach of even the lowest emission wavelength range of the CFL bulb. Ir(ppy)3 also gave no reaction. This was interesting, considering that its triplet energy (T1 = 57.8 kcal⋅mol−1) was similar to Selectfluor® (T1 = 61.4 kcal⋅mol−1). Benzophenone (T1 = 69.1 kcal⋅mol−1) and 9-fluorenone (T1

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• -mannose (the α-anomer also shows biological activity, but to a lesser extent) [13][14][15], a short-chain (citronellol) mimic of dolichol [1][2][13], and a functional tag. The latter may either be a chemically reactive group (in MPC-1) or a fluorescent reporter group (in MPC-2). MPC-1 bears a benzophenone

• MPC-1 and MPC-2. Compound β-4Ac-Man-CEP was prepared in 4 steps from ᴅ-mannose (see Supporting Information File 1) [35][36]. Compound Cit-BZP-yne was prepared via a Mitsunobu reaction of tetrahydropyranyl (THP)-protected citronellol and a hydroxylated benzophenone derivative [10][37][38]. Compound Cit

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• radicals with the formation of a C–O bond (dimer 4b, oxidation of diisopropyl oxime 1b), an O–N bond (dimer 4c, oxidation of benzophenone oxime 1c), and an N–N bond (dimer 4d, oxidation of benzaldoxime 1d, see also [58]) was observed. As a rule, the initial dimers of iminoxyl radicals are unstable, which

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• compared to other methods for radical generation [56]. Within this field, organic dyes can act as competent photocatalysts for direct HAT processes. Specifically, upon light excitation, photoactive carbonyl compounds, such as benzophenone and its derivatives, reach an electronically excited triplet state

• : a biradical capable of abstracting an H atom from C–H bonds. Recently, Martin exploited this feature in a nickel-catalyzed process for the alkylation of arenes (Scheme 8) [57]. In this report, the excited state of a push–pull benzophenone OD10 can abstract an H atom from the substrate

• -hydroxyphthalimide (NHPI, OD22, similar to the benzophenone photocatalysts OD9 and OD10) can abstract an H atom from the aldehyde substrate 20.1. The resulting acyl radical adds to the (E)-β-nitrostyrene 20.2, and the following denitrosylation affords the chalcones 20.3. Alkenyl and aryl radical ions (radical

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• restriction of intramolecular motions [23]. Moreover, crystalline 2,5-dihexyloxy-4-bromobenzaldehyde displays green phosphorescence, which stems from rapid ISC due to the heavy atom effect via halogen bonding (C=O···Br) [24]. Moreover, benzophenone- or benzil-type molecules can achieve long-lived

Fluorinated phenylalanines: synthesis and pharmaceutical applications

• Laila F. Awad and
• Mohammed Salah Ayoup

Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91

• -[18F]fluorophenylalanines 72a,b [54] were achieved by a copper-mediated nucleophilic radiofluorination of arylstannanes 71a,b with [18F]KF (Scheme 17). 1.6. Alkylation of benzophenone imine of glycine ester Pentafluoro-ʟ-phenylalanine (77a) and 2,4-ditrifluoromethyl-ʟ-phenylalanine (77b) were

• synthesized through alkylation of the benzophenone imine of glycine ester 73, with perfluorinated benzylbromide 19c or 2,4-bis(trifluoromethyl)benzyl bromide (74) in the presence of 2,7-bis[O(9)-allylhydrocinchonidinium-N-methyl]naphthalene dibromide, to afford the fluorinated phenylalanine imines 75a,b with

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• capable to induce other types of reactions, such as hydrogen atom abstraction (HAT) processes or triplet state energy transfer processes (EnT). Carbonyl compounds, especially diaryl ketones, have shown great potential as far as their catalytic scope is concerned. Benzophenone or acetophenone (64) and

• that did not react with the excited benzaldehyde (9, Scheme 2). Photoorganocatalysts are known for their ability to abstract hydrogen atoms from various substrates, furnishing radical species. Benzophenone is a very well-studied example of this category. Alongside with benzophenone and acetophenone

• , McGinniss and co-workers reported the polymerization of methyl methacrylate (26, MMA) by employing 4,4’-bis(N,N-diethylamino)benzophenone (27, DEABP) as the photoinitiator (Scheme 7) [35]. It was already well-accepted that aminoaromatic compounds, such as Michler’s ketone (28) and DEABP (27), present large

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• -free ATRP strategy [132][133][134][135][136][137]. Latter reference provided a comprehensive overview demonstrating the function of phenothiazine derivatives, perylene, diaryl dihydrophenazines, anthracene or pyrene. In addition, type II photoinitiators including benzophenone, and thioxanthones were

Formal preparation of regioregular and alternating thiophene–thiophene copolymers bearing different substituents

• Atsunori Mori,
• Keisuke Fujita,
• Chihiro Kubota,
• Toyoko Suzuki,
• Kentaro Okano,
• Takuya Matsumoto,
• Takashi Nishino and
• Masaki Horie

Beilstein J. Org. Chem. 2020, 16, 317–324, doi:10.3762/bjoc.16.31

• RINT-2000(CuKα) device. Concerning the solvent of the nickel- and palladium-catalyzed reactions, THF (anhydrous grade) was purchased from Kanto Chemical Co. Ltd. and passed through alumina and copper columns (Nikko Hansen & Co. Ltd.) or distilled from a sodium dispersion in mineral oil/benzophenone

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• Table 2. In the absorption spectra, 2 and 5 both showed intense π–π* absorption bands localized on the benzophenone at 326 and 310 nm, respectively [37]. The extra TPA donor in 5 contributed to a red-shifting of this absorption band. There were low-energy CT bands from the TPA donor to the BQ acceptor

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• . Commercially available reagents and solvents were used as received unless otherwise stated. THF and diethyl ether were distilled over sodium/benzophenone. Acetonitrile and dichloromethane were distilled over calcium hydride immediately before use. Compounds 1a and 2 were synthesized according to literature

• argon over sodium benzophenone ketyl. CH2Cl2 was distilled over CaH2 under argon. Mass spectrometry was performed at the CESAMO analytical center (University of Bordeaux, France) on a QStar Elite mass spectrometer (Applied Biosystems). The instrument is equipped with an electrospray ion (ESI) source and

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

• the Re-face in both cases (Scheme 58). Magdesieva and his group developed an electrochemical method for the deprotonation of a Ni(II) glycinate complex containing (S)-o-[N-(N-benzylprolyl)amino]benzophenone [(S)-BPB] 188 as an chiral auxiliary moiety and explored its applicability in

Multiple threading of a triple-calix[6]arene host

• Veronica Iuliano,
• Roberta Ciao,
• Emanuele Vignola,
• Carmen Talotta,
• Patrizia Iannece,
• Margherita De Rosa,
• Annunziata Soriente,
• Carmine Gaeta and
• Placido Neri

Beilstein J. Org. Chem. 2019, 15, 2092–2104, doi:10.3762/bjoc.15.207

• mass spectra were calibrated externally, and a linear calibration was applied. All chemicals were reagent grade and were used without further purification. Tetrahydrofuran was dried by heating under reflux over sodium wire in the presence of benzophenone as indicator while dimethylformamide was dried

One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion

• Christina Görgen,
• Katharina Boden,
• Guido J. Reiss,
• Walter Frank and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1360–1370, doi:10.3762/bjoc.15.136

• -dione (3a) revealed that the use of KOH dried triethylamine instead of the initial preconditioning (Na/benzophenone dried) led to a reduction of the reaction time t1 from 24 to 15 h (see Supporting Information File 1, Table S1). In addition, the concentration could be doubled and the obtained yield of

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• benzophenone until the dark blue color of the solution persisted. Then, the solvents were distilled under nitrogen and taken from the distillation flask, which was closed by a septum, by syringes or cannulas. 2,5-Dimethoxyacetophenone (6c) and 4-methoxystyrene (7b) were purchased from Sigma-Aldrich. 2,5

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• groups were removed by concentrated acid. A very efficient synthesis of (2S,3S,4S)-4 starts from another serine-derived chiron, namely O-benzyl-N-Boc-D-serine [111], which was readily transformed to the Z-olefin 120 containing a benzophenone imine residue as a nitrogen protecting group (Scheme 29

• of (+)-polyoxamic acid (Scheme 30) [113]. To this end the anion generated from benzophenone imine of tert-butyl glycinate 124 acted as a Michael donor in the presence of homochiral catalyst to give a ca. 1:1 mixture of diastereoisomeric iminoselenides 125 with an ee up to 96% (Scheme 30). Next, a 9

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

• Tegene T. Tole,
• Johan H. L. Jordaan and
• Hermanus C. M. Vosloo

Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19

• bromopyridines were reacted with benzophenone followed by a reaction of the lithiated alcohol with 2. Four new ruthenium alkylidene complexes, i.e., 6–9 (Figure 4), were successfully obtained and investigated as precatalyst in 1-octene metathesis in the temperature range 40–110 °C. The stability, selectivity and

• time 10 min); 110 to 290 °C at 25 °C/min (hold time 16 min). Reagents: 2-Bromo-3-methylpyridine (95%), 2-bromo-4-methylpyridine (97%), 2-bromo-5-methylpyridine (98%), 2-bromo-3-methoxypyridine (97%), n-BuLi (2.5 M in hexane), benzophenone (99%), 2-N,N-dimethylaminoethanol (≥ 99.5%), Grubbs 2 (2) (97

• %), 1-octene (99% GC), nonane (reagent plus 99%) and toluene (99%) were purchased from Sigma-Aldrich. Toluene-d8 (99.5%) was purchased from MERCK and tert-butyl hydrogen peroxide (80%) from Riedel-de Haen. Diethyl ether and THF were dried over Na in the presence of benzophenone. Pentane was distilled

Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion

• Rudolf Knorr and
• Barbara Schmidt

Beilstein J. Org. Chem. 2018, 14, 3018–3024, doi:10.3762/bjoc.14.281

• view of the apparently modest spatial demand of the α-cyano substituent in the adducts of 2Li, it seemed surprising that the following ketones generated no (or no kinetically stable) C=O adducts at rt: t-Bu2C=O, pivalophenone (t-Bu–C(O)–Ph), benzophenone (Ph2C=O) [7], bis(1-methylcyclopropyl)ketone [8

1,8-Bis(dimethylamino)naphthyl-2-ketimines: Inside vs outside protonation

• A. S. Antonov,
• A. F. Pozharskii,
• P. M. Tolstoy,
• A. Filarowski and
• O. V. Khoroshilova

Beilstein J. Org. Chem. 2018, 14, 2940–2948, doi:10.3762/bjoc.14.273

• sponge moiety: for example, the basicity of benzophenone imine (pKa = 6.82) and even that of cyclohexanone imine (pKa = 9.15) [12] is much lower than that of DMAN (pKa = 12.1) [1][2]. Moreover, as it was already mentioned in the introduction, this is the third known example of a DMAN derivative with a

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• products 27d (Scheme 19) [64]. The N–H imines overcame substrate scope limitation from previous reports with N-aryl and N-alkylimines. Moreover, multiple C–H alkylation was also succeeded with benzophenone imines in high yields with linear selectivity under the mild reaction conditions. In contrast, the

Novel photochemical reactions of carbocyclic diazodiketones without elimination of nitrogen – a suitable way to N-hydrazonation of C–H-bonds

• Liudmila L. Rodina,
• Xenia V. Azarova,
• Jury J. Medvedev,
• Dmitrij V. Semenok and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2018, 14, 2250–2258, doi:10.3762/bjoc.14.200

• with CH2- and O-bridges in their structure, diazoindandione 1f, diazocyclopentenedione 1g, and as a С–Н donor tetrahydrofuran was employed in the study (Figure 1). To determine the most efficient conditions for this reaction with diazodiketones 1, three sensitizers, acetophenone, benzophenone, and

• used in this study (acetophenone, benzophenone and Michler’s ketone) demonstrate that they show appropriate absorption of the actinic light at the irradiation conditions of diazodiketones 1 (Supporting Information File 1, Table S2). The sensitized photoreactions of diazodiketones 1a–g were carried out

• % (Table 1, entries 1 and 3). The irradiation of tricyclic diazodiketone 1b in the presence of 1 equiv of benzophenone in THF solution led to the formation of hydrazone 2b in a yield of 32% (Table 1, entry 4), whose structure was unambiguously established by X-ray analysis (Figure 2). To increase the