Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• derivatives. Upon abstraction of a hydride from tris(trimethylsilyl)silane (TTMS) by an excited benzophenone derivative, the formed silane radical can undergo a XAT with an alkyl bromide to generate an alkyl radical. Consequently, the alkyl radical undergoes a Giese-type reaction with the Dha derivative

• photocatalyst (Figure 1d) [25]. Noël et al. [26] have further extended this approach to include alkyl bromides (Figure 1e) [26]. Despite the effectiveness of the photolysis, benzophenone derivatives have also been shown to enhance the productivity of silane-mediated conjugate additions, using alkyl halides [27

• in aqueous solution, meeting important requirements with regard to bioorthogonal chemistry [38]. Considering previous research that demonstrated photochemical hydrogen atom abstraction by benzophenone derivatives from trialkylsilyl hydrides [27], as well as advances in alkyl radical formation using

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• abilities has been verified by mathematical calculations. Keywords: decarbonylation–oxidation; hydroperoxide; 2-hydroxybenzophenone; transition-metal-free; UV-protection; Introduction Benzophenone compounds are ubiquitous in nature, and show biological activities such as anti-inflammatory, antiviral, and

• substitution at the 4-position of benzofuranone hindered the reaction, leading to a very poor yield of the desired benzophenone product. Further, to confirm the structure and the substitution pattern in the 2-hydroxybenzophenones, single crystal XRD data were collected for the representative compounds 4ja, 4fb

• a bulky substitution at the 7-position of the benzofuranone also hinders the formation of 2-hydroxybenzophenone, we prepared 3,7-diphenylbenzofuran-2-one (3ma). However, on heating 3ma with Cs2CO3 in THF, the corresponding benzophenone 4ma was obtained, which confirmed that a bulky substituent in

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• bromides and other reagents were used as they were received from commercial suppliers, unless otherwise noted. THF and Et2O were dried over sodium-benzophenone and distilled prior to use. 1H NMR spectra were recorded at 300 and 400 MHz, and 13C NMR spectra at 75 and 100 MHz, in CDCl3 or DMSO-d6 using TMS

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• was obtained by the addition of allylmagnesium bromide to benzophenone imine on a 3 gram scale in 80% yield. The rearrangement products 114 were readily converted to free homoallylic amines employing hydroxylamine in THF. The reaction showed moderate to high yields on various aromatic aldehydes, being

• of the allyl donor reagent (up to 25 g). Importantly, benzophenone was easily recovered by recrystallisation after the workup (no chromatography, 80% yield) and then converted back into the allyl donor 116 (86% yield), thus boosting the overall atom-economy of the process. Also, the recovery of the

• methallyl derivative 130, the stereoselectivity dropped to a modest level (dr 5:1, ee 60%, yield 60%), whereas higher allyl homologues such as phenyl and benzyl proved to be inactive (Scheme 26). The synthetic utility of the resulting homoallylic N-benzophenone imines 131 was illustrated on a laboratory

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• electrochemical synthesis of diazo compounds from hydrazones. Transformations involving diazo compounds as either products or intermediates are covered. While investigating the electrochemical oxidation of benzophenone hydrazones 130, Chiba et al. discovered that several products were obtained depending on the

• sodium methoxide in an undivided cell, three main products (namely benzophenone dimethyl acetals 133, diphenylmethyl methyl ethers 134 and diphenylmethanes 135) were obtained, the ratio of which was influenced by the electrode materials, the temperature and the amount of sodium methoxide. The range of

• diazo compounds to react with alkenes, Chiba et al. developed the electrochemical construction of diphenylcyclopropanes 137 from benzophenone hydrazones 130 and methacrylic acid derivatives 136. The transformation was conducted on a large scale (60 mmol) in an undivided cell using graphite anode and

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• were used as received, without further purification. Solvents and air-sensitive reagents were distilled under a dry nitrogen atmosphere. Dry THF was distilled from sodium benzophenone ketyl. A Nafion N115 film was acquired from FuelCell Store and a 20 wt % mixture in lower aliphatic alcohols and water

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• was observed for the yields depending on the substitution pattern. Instead, the individual purity and quality of the dienes played an important role. Reflux of an EtOH solution of 23a in the presence of PTSA (para-toluenesulfonic acid) afforded benzophenone 24a in 50% yield. The reaction of 6a–r with

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• ]. Prominent examples include: (i) carbonyl compounds such as benzophenone [31][32] and thioxanthone [33][34][35], (ii) TADF emitters with small singlet-triplet energy splitting [8][36], (iii) substitution with heavy atoms such as sulphur [37] and halides [38] for fast ISC, or a combination of the above

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• calculated respectively for C60, 2, and 3. Experimental Materials and general method: All chemicals were reagent grade, purchased from commercial suppliers. o-Dichlorobenzene (ODCB) was distilled from P2O5 under vacuum before use. Toluene was distilled from benzophenone sodium ketyl under dry N2 prior to use

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• -workers adopted a similar intramolecular [2 + 2] cycloaddition using benzophenone as a triplet sensitizer to access 1,5-BCHs (±)-59a–e as racemic mixtures of endo:exo diastereomers (Scheme 5A) [42]. Basic hydrolysis of the ester moiety followed by recrystallisation gave the diasteromerically pure acid

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• benzophenone moiety in probe 3. The samples were then reacted with TAMRA-N3 (structure shown in Figure S4, Supporting Information File 1) under copper(I)-catalyzed azide–alkyne cycloaddition conditions [21] and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis coupled with in-gel

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• a higher energy level or even the vacuum, generating radical species. The energy of UV photons is comparable to the energy of chemical bonds [163], and therefore photons are particularly suitable for driving chemical reactions on polymer surfaces. Benzophenone is the best-established source of

• radicals on polymer surfaces. Its photoexcitation and subsequent reaction with polymers have been studied for decades [164][165][166]. When irradiated at around 360 nm, benzophenone undergoes excitation to a triplet state with biradical behavior. It then abstracts a hydrogen atom from the polymer resulting

• well-defined polymer brushes from polymer surfaces [170][171]. Photoinduced processes, including photoATRP and PET-RAFT were used [172][173][174][175]. Poly(aryl ether ketone)s such as poly(ether ether ketone), bearing a diaryl ketone moiety resembling that of benzophenone, can generate biradicals upon

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

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• position gave benzophenone in 80% yield with a trace of N-benzenesulfonylketimine 2m under the optimized reaction conditions. Likewise, N-(arylsulfonyl)benzylamine 1n having a methyl group present at the benzylic position gave product 2n only in a trace quantity. To demonstrate further the scalability of

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• cyclization (Scheme 51A) [93]. The reaction starts with the coordination of the Rh catalyst to the propargyl alcohol 198. In the presence of a base, the rhodium–alkynyl reagent is generated with the concomitant extrusion of benzophenone. Finally, the alkynylation of the enone is followed by the cyclization

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• 40 °C. The phosphine ligand (574.40 mg, 2.19 mmol, 1 equiv) dissolved in THF (0.11 M) was then added to the middle. The mixture was stirred at room temperature and treated dropwise with a solution of sodium benzophenone ketyl (about 0.05 equiv added) in THF (0.027 M) via a syringe until the phosphine

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• -Cl [21], 3,4-di-Cl [21][22], 2/3/4-F [23]) were inserted in the N-benzyl moiety as well as in the aromatic rings of the benzophenone fragment [24][25][26] (selected examples are given in Scheme 1). Insertion of halogen atoms increased enantioselectivity, e.g., in alkylation reactions [27][28

• ]. Functionalization of the phenyl ring in the benzophenone gives rise to an additional axial chirality (L3), thus improving stereoselectivity observed at the removed stereocenter [24][25]. Replacing N-benzylproline for 2,7-dihydro-1H-azepine (L5) allowed obtaining a new tridentate ligand with chemically stable axial

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• for a given ligand. Experimental General All reactions and manipulations were carried out under dry pure N2 using standard Schlenk techniques. All solvents were distilled from sodium/benzophenone and stored under nitrogen before use. The NMR spectra were recorded on a Bruker MSL-400 spectrometer (1H

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• completion of the total synthesis via the preparation and coupling of the fragment 5 is under study in our laboratory. Experimental Unless otherwise stated, all reactions were conducted in oven-dried glassware under an atmosphere of dry argon. Tetrahydrofuran was distilled over sodium/benzophenone ketyl

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

• configuration to the α-stereocenter as (R) in both thermodynamically and kinetically controlled isomers of 10. The configurations of the β-stereocenter in the obtained diastereomers of 10 are different, as follows from the different correlations of the ortho-phenyl protons of the benzophenone moiety observed in

Electrochemical formal homocoupling of sec-alcohols

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masashi Shiota,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108

• ][41][42][43][44]. The group of Wang recently reported the sacrificial anode-free electroreduction of benzophenone derivatives to afford vic-1,2-diols using over-stoichiometric NaN3 under acidic conditions, but appropriate precautions should be taken for in situ-generated explosive and toxic HN3 [45

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

• . The reduction of benzophenone also did not proceed smoothly, and only 13% of benzophenone was converted. These results suggest that a Pd/C cathode significantly targets an alkene moiety over a carbonyl group, predominantly leading to the reduction of the C=C moiety. Finally, the electroreduction of 1a

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• Shimadzu IRAffinity-1 infrared spectrometer. HRMS were measured on a Thermo Scientic Exactive FTMS spectrometer. Melting points were uncorrected. Column chromatography was performed on silica gel 60. THF was distilled from sodium benzophenone ketyl radical. TMSCl, TEA, and DMF were distilled from CaH2

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• as methanol, phenolic DTBMP, benzyl bromide, aldehydes, and benzophenone. For both benzyl bromide and benzophenone, their alkylations occurred only at the γ-position of the phenyl group in phenylphosphonodiamides due to less bulkyness (Scheme 28) [54]. They finally extended their strategy to alkyl

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• others. Experimental General procedures and materials Tetrahydrofuran (THF) for use on vacuum line was freshly distilled from sodium/benzophenone prior to use. n-BuLi (hexane) were obtained from Energy Chemical; prior to use, its concentration was determined by titration with N-pivaloyl-o-toluidine [42