Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• various reaction categories. The system consists of a liquid–liquid separator and an in-line/online analytical tool to facilitate closed-loop autonomous optimization. The capability of the system was demonstrated in the optimization of C–C and C–N cross-coupling, olefination, reductive amination

• , utilizing a custom Python package developed in-house [53]. This approach enabled us to track the conversion process at different residence times. Specifically, we quantified the conversion by analyzing the area under the curve (AUC) of the Raman-active vibrational modes associated with the styrene–vinyl C=C

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• -tropone” in literature [1][2], although it should be named as 9H,18H,27H-hexabenzo[c,c′,c′′,f,f′,f′′]benzo[1,2-a:3,4-a′:5,6-a′′]triscycloheptene-9,18,27-trione according to the IUPAC nomenclature. We became interested in compound 1 because its polycyclic skeleton presents a key structural unit in carbon

• synthesized according to the procedures detailed in Supporting Information File 1. In this reaction, the first step of diazo–thioketone coupling occurred at 50 °C in THF, and the second step of desulfurization with triisopropyl phosphite occurred in refluxed toluene, giving diene 10 in a yield of 47%. The

• room temperature yielded partially fused nanographene 3 (20%), with formation of six C–C bonds giving four six-membered rings and two five-membered rings. Performing this reaction at a higher temperature led to a lower yield of compound 3 and the formation of byproducts with lower Rf values on thin

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• delight, by treatment of 5 with substituted carbazoles 6 in the presence of Cs2CO3 (5.0 equiv) in DMF at 100 °C, seven 2,8-bis(9H-carbazol-9-yl)-5-phenylbenzo[b]phosphindole 5-oxide derivatives 7 were furnished in good to excellent yields (77–91%). The structural characterization of the obtained molecules

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• %). This cascade involves an initial Suzuki–Miyaura cross-coupling reaction between 1,8-dihalonaphthalenes and heteroarylboronic acids or esters, followed by an intramolecular C–H arylation under the same conditions to yield the final heterocyclic fluoranthene analogues. The method was further employed to

• total synthesis of the fungal natural product bulgarein. Keywords: acenaphthylene-fused heteroarenes; benzo[j]fluoranthenes; C–H arylation; fluoranthenes; heterocycles; Introduction An important subclass of polycyclic aromatic hydrocarbons (PAHs) [1] is comprised of fluoranthenes, which have been the

• -based natural product, which was discovered to induce topoisomerase I-mediated DNA cleavage [16][17]. For the construction of the fluoranthene skeleton, a broad range of synthetic strategies including C–H arylation [18][19][20][21][22], Diels–Alder [7][8][23][24][25] and [2 + 2 + 2] cycloadditions [26

Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• Beatriz Dedeiras Catarina S. Caldeira Jose C. Cunha Clara S. B. Gomes M. Manuel B. Marques LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, NOVA FCT , 2829-516 Caparica, Portugal 10.3762/bjoc.20.272 Abstract The reactivity of our recently disclosed hypervalent iodine

• as strong oxidizing agents [1], during the last decades HIRs have been investigated as group-transfer reagents, useful in several bond-forming reactions, such as in C–C, C–N, and C–O [2][3][4][5]. The benziodoxol(on)e family, cyclic iodine(III) reagents, stands out for their thermal stability and

• benziodoxolone, 2d) were obtained with quantitative yields, as white solids on the gram-scale, easy to manipulate and long-term stable below 0 °C. Crystals of compound 2d were successfully obtained and its molecular structure was confirmed through single-crystal X-ray diffraction. The X-ray analysis revealed a

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

• , forming a new C(sp3)–C(sp3) bond. The reaction can be performed in a phosphate-buffered saline (PBS) solution and shows post-functionalization prospects through pathways involving classical peptide chemistry. Keywords: dehydroalanine; Giese-type reaction; hydroalkylation; photocatalysis; water

• ; Introduction The construction of C(sp3)–C(sp3) bonds is a highly important target in synthetic organic chemistry. Historically, polar conjugate additions have been a benchmark method for constructing these bonds by functionalizing an electron-deficient olefin [1][2][3]. Recently, however, radical-based

• )silane and a substoichiometric amount of (4-methoxyphenyl)(4-(trifluoromethyl)phenyl)methanone (BP l) (Table 1) [26][27]. The reaction was performed in batch, using a 390 nm Kessil UV-A lamp, stirring at 600 rpm overnight at 25 °C (see Supporting Information File 1 for a more detailed optimization). The

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• commercial perfluoroarene chemical blocks and reagents, involving catalyzed C–F-bond activation and cross-coupling reactions, usually requiring precious transition-metal catalysts and tedious synthetic routes [28][29][30][31][32][33][34]. Therefore, low-cost and facile synthetic strategies are desired to

• the Janus Fn derivatives exhibit a hexagonal columnar liquid crystal phase (Colhex), with clearing temperatures decreasing gradually with the elongation of the alkoxy side-chains, from nearly 200 °C for the shortest homologs down to ca. 100 °C for the dodecyloxy derivative. The larger lath-like

• compounds, Gnm, exhibit a rectangular columnar phase (Colrec) also over large temperature ranges from ambient up to 183 and 164 °C, respectively. The unsymmetrically alkoxy-substituted derivative, G48, also displays a Colrec over a similar temperature range. The compounds’ photophysical properties have also

Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• Abstract The C–H arylation of 2-quinolinecarboxyamide bearing a C–Br bond at the N-aryl moiety is carried out with a palladium catalyst. The reaction proceeds at the C–H bond on the pyridine ring adjacent to the amide group in the presence of 10 mol % Pd(OAc)2 at 110 °C to afford the cyclized product in 42

• % yield, respectively. The related reaction is also carried out with amides of non-pyridine derivatives terephthal- and benzamides to afford multiply fused heterocyclic compounds in 81% and 89% yields, respectively. Keywords: intramolecular C–H arylation; multiply fused heterocycles; palladium acetate

• ; phosphine ligand; pyridine amides; Introduction Transition-metal-catalyzed synthetic reactions have recently attracted much attention in synthetic organic chemistry [1][2]. C–H Arylation reactions catalyzed by a transition metal are of particular interest because these reactions involve rather superior

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• (Scheme 3). The reaction of 3-isothiocyanatooxindoles 4 and ketimines 7 led to the (3 + 2) cycloaddition through the C=C bond of the α,β-unsaturated imine instead of the C=N bond, affording various spirocyclic derivatives 8 with excellent yields (92–98%), diastereoselectivities (15:1–20:1 dr), and

• alcohol E isomer and it coordinated to the squaramide in an effective orientation, a stepwise mechanism is taking place. Firstly, the dienolate adds to the azadiene which is followed by cyclization with formation of the C–N bond. Finally, protonation leads to the formation of the desired derivative. The

• alternative pathway which occurs is the transformation of the α,β-unsaturated imine into the corresponding enamine C, which attacks to the azlactone leading to the addition subproduct 49’, also observed in the catalytic reactions. Also in 2020, Lu and co-workers reported an enantioselective dearomatization of

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• (partial structures a and b, respectively, in Figure 2), which were characteristic of psammaplysins, in ceratinadin G (1) was suggested by comparison of its 1H and 13C NMR data with those of known psammaplysin derivatives such as psammaplysins A and F (2) [4][5][6][10][11][12]. HMBC correlations (H-1/C-2

• , H-1/C-3, H-1/C-6, H2-5/C-3, H2-5/C-4, H2-5/C-6, H-5a/C-7, H-7/C-8, and 3-OCH3/C-3) supported the presence of the 8,10-dibromo-9-methoxy-1,6-dioxa-2-azaspiro[4.6]undeca-2,7,9-trien-4-ol unit (partial structure a in Figure 2). While the existence of the 11-N-methylmoloka'iamine unit (partial structure

• b in Figure 2) was confirmed by the 1H-1H COSY and TOCSY correlations (C-10–C-12 and C-19–C-20), and HMBC correlations (H2-12/C-13, H-15/C-14 (H-17/C-18), H-15/C-19 (H-17/C-19), H-17/C-13 (H-15/C-13), H-17/C-15 (H-15/C-17), and H2-20/C-16). HMBC correlations between the N-methyl protons H3-21 (δH

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• , Don Young Road, Brisbane, 4111, Australia 10.3762/bjoc.20.266 Abstract The marine sponge Suberea ianthelliformis was investigated for new chemistry after the recent discovery that polyamines ianthelliformisamines A–C (1–3) – originally sourced from this Australian sponge – act as Pseudomonas

• ], therefore it is no surprise that sponges are highly sought after for novel bioactive metabolites and have been a major focus of marine natural product drug discovery for over 70 years. The identification of ianthelliformisamines A–C from the Australian marine sponge Suberea ianthelliformis, which displayed

• activity against both Pseudomonas aeruginosa and Staphylococcus aureus, has contributed to a surge in the interest of polyamines as new antibacterial leads [6]. To date the total synthesis of ianthelliformisamines A–C (1–3) has been described [7] and numerous synthetically related analogues have been

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• proven useful in various Cu- and Pd-catalysed C–X-bond-forming strategies [43][44][45][46][47][48][49][50][51], including widespread use across several CuAAC methodologies [52][53][54]. Germanium-based functional groups have recently emerged as highly useful components for transition-metal-catalysed

• cross-couplings. Schoenebeck and co-workers have shown that Ge-based compounds are versatile reagents within chemoselective cross-coupling processes for the formation of a variety of C–C and C–X bonds [55][56][57][58][59][60][61][62][63]. Importantly, these transformations can take place in the presence

• ) Functionalisation of germylated triazoles. Isolated yields unless stated. (i) Pd(PPh3)4 (10 mol %), 2-bromothiazole (1.2 equiv), KCl (3.0 equiv), PhMe/EtOH 4:1, N2, 100 °C, 16 h. NMR yield in parentheses. (ii) Pd2(dba)3 (2.5 mol %), iodobenzene (1.5 equiv), AgBF4 (1.5 equiv), DMF, N2, 80 °C, 16 h. (iii) NBS (2.0

Synthesis of 2H-azirine-2,2-dicarboxylic acids and their derivatives

• Anastasiya V. Agafonova,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2024, 20, 3191–3197, doi:10.3762/bjoc.20.264

• included oxidation of aldehydes 4 with Oxone to acids 5 and the conversion of the latter into acid chlorides with thionyl chloride. The first reaction sequence was suitable for obtaining compounds 1a–c,e,f with substituents tolerant to radical reaction conditions. A significant advantage of the method is

• complex, which facilitates the cleavage of the N–O bond and subsequent 1,3-cyclization, ultimately leading to the formation of 2H-azirine. Therefore, the isomerization of isoxazole 1j was carried out at a higher temperature, 82 °C, but after hydrolysis of the reaction mixture, instead of the expected

• because the isomerization of 3-(tert-butyl)-5-chloroisoxazole-4-carbonyl chloride did not occur at room temperature, but at elevated temperature (82 °C) the reaction proceeded via the formation of the nitrile ylide, which cyclized to 2-(tert-butyl)-5-chlorooxazole-4-carbonyl chloride. 3-Phenyl-2H-azirine

Direct trifluoroethylation of carbonyl sulfoxonium ylides using hypervalent iodine compounds

• Radell Echemendía,
• Carlee A. Montgomery,
• Fabio Cuzzucoli,
• Antonio C. B. Burtoloso and
• Graham K. Murphy

Beilstein J. Org. Chem. 2024, 20, 3182–3190, doi:10.3762/bjoc.20.263

• Radell Echemendia Carlee A. Montgomery Fabio Cuzzucoli Antonio C. B. Burtoloso Graham K. Murphy São Carlos Institute of Chemistry, University of São Paulo, 13560-970, São Carlos, SP, Brazil Department of Chemistry, University of Waterloo, 200 University Ave W., Waterloo, Ontario, Canada

• ]. This synthetic potential has been demonstrated in a range of insertions into polar bonds [17][18][19][20], C−H activation transformations [21][22][23], and geminal difunctionalizations [24][25]. Within the literature, a broad array of classical methods describes the synthesis of sulfoxonium ylides [26

•  1, entries 9–12). We attempted to decrease the reaction time by increasing the temperature, but these changes resulted in decreased yields of 3a (Table 1, entries 13 and 14). Surprisingly, when using microwave (MW) heating at 70 ⁰C for 10 min in ACN, product 3a was formed in 74% yield (Table 1

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• , Tomilov et al. described the formation of tetrahydropyridazine 3,4,5,6-tetracarboxylic esters in 42% yield upon the decomposition in chloroform at 60 °C of methyl diazoacetate in the presence of pyridine and catalyzed by rhodium(II) acetate (Scheme 1b) [24][25]. More recently, an unusual [4 + 2

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• inhibitors, and their effects were investigated using the Amplex-Red® kit in C. elegans. Individuals exposed to compounds 2a, 2b, 2c, 2d, 2e, and 2f at a concentration of 1 mM were analyzed for AChE activity in their extracts. The results revealed significant inhibition of AChE levels, with compound 2e

• a multicomponent reaction to obtain SIRT2 inhibitors (Scheme 12). The authors suggest a Knoevenagel condensation approach between isatin derivatives and ethyl cyanoacetate, followed by a Michael addition with C–H activated carbonyl compounds and intramolecular cyclization [50]. They synthesized 45

• /intramolecular Ullmann-type C–N coupling reactions. Azido-Ugi 4CR/cyclization (AU-4CR) strategy: The azido-Ugi four-component reaction (AU-4CR) is an elegant and atom economical approach for obtaining substituted tetrazoles, which are very relevant in medicinal chemistry [64]. When combined with suitable post

Surprising acidity for the methylene of 1,3-indenocorannulenes?

• Shi Liu,
• Märt Lõkov,
• Sofja Tshepelevitsh,
• Ivo Leito,
• Kim K. Baldridge and
• Jay S. Siegel

Beilstein J. Org. Chem. 2024, 20, 3144–3150, doi:10.3762/bjoc.20.260

• –Loschmidt (CL) "elements" [10][16]. For corannulene, a maximum of two CL elements (sextets) are present in any one resonance form. Therefore, applying the CL perspective to BFC and FIC one sees dibenzofluorene (full name 13H-dibenzo[a,c]fluorene) as a cognate, which highlights these compounds to be like a

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF₅- and CF₃SF₄-containing [2]staffanes

• Jón Atiba Buldt,
• Wang-Yeuk Kong,
• Yannick Kraemer,
• Masiel M. Belsuzarri,
• Ansh Hiten Patel,
• James C. Fettinger,
• Dean J. Tantillo and
• Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

• Jon Atiba Buldt Wang-Yeuk Kong Yannick Kraemer Masiel M. Belsuzarri Ansh Hiten Patel James C. Fettinger Dean J. Tantillo Cody Ross Pitts Department of Chemistry, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, U.S.A. 10.3762/bjoc.20.259 Abstract Selectivity in radical chain

• nanotechnology [5], liquid crystal design [6][7][8][9][10], and the study of energy-transfer [11][12] or electron-transfer [13][14][15][16][17] processes. We also posit that lower-order [n]staffanes (i.e., n = 2 or 3) are potentially valuable C(sp3)-rich bioisosteres [18][19] that have been seemingly overlooked

• cooling; this highlights that the [2]staffanes synthesized during this study are also interesting from a fundamental structural standpoint. Results and Discussion Over the past few years, our group has begun to establish strain-release pentafluorosulfanylation as a viable strategy for C(sp3)–SF5 bond

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• Charu Bansal Oliver Ruggles Albert C. Rowett Alastair J. J. Lennox University of Bristol, School of Chemistry, Bristol, BS8 1TS, UK 10.3762/bjoc.20.258 Abstract The chemistry of hypervalent iodine (HVI) reagents has gathered increased attention towards the synthesis of a wide range of chemical

• fluoride ion to displace PhI. In pathway B (bottom), the nitrogen is oxidised by the iodane, generating an electrophilic intermediate B. Nucleophilic attack by the double bond subsequently forms the 6-membered ring intermediate C, which is either immediately attacked by fluoride to form both cis and trans

• C‒F bond to give predominantly the trans product, but this pathway competes with a less favourable SN2 nucleophilic attack by fluorine to form the cis product. However, a mechanism entirely mediated by the I(III) HVI reagent, with the Pd(OAc)2 only acting as a Lewis acid to activate the HVI reagent

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• used three different types of macrocycles: calix[4]pyrroles 11, 17a–c, porphyrin 18, and calix[4]arene 19 (Figure 4a). Despite the presence of –OH and –NH binding sites, both calix[4]arene 19 and porphyrin 18 showed only a negligible activity compared to calix[4]pyrroles (11, 17a–c), which provided

• ones with secondary amine side arm (48d, 48g, h) were catalytically active for Michael additions, providing 60–71% yields (Table 3), whereas tetraalkylated analogues (49a–g) and dialkylated OxPs without a secondary amine side arm (48a–c, 48e and 48i) were not. Based on these results, the authors have

• conditions (catalyst/TBACl/aziridine 1:5:100 and 1.2 CO2 MPa at 125 °C) [71]. Out of all the used macrocycles, the unsubstituted H2TPP (18)/TBACl system turned out to be the best, giving up to 95% yield for the both N-alkyl/arylaziridine substrates with regioisomeric ratios up to 95:5 (70b:71b) for R = n-Bu

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• efficiency and creating six new bonds (two C–C, three C–N, and one N–N). Additionally, the products were evaluated against breast cancer MCF-7 cells, finding moderate activity in the compounds substituted with fluorine and chlorine. Keywords: 1,5-disubstituted tetrazoles; high-order multicomponent reaction

• described (Scheme 1a–c). In 2021, Dömling’s research group synthesized a series of 1,5-disubstituted tetrazole-indoles 6 in good to excellent yields via an Ugi-azide/acidic ring-closure sequence [20]. Balalaie described an efficient method in 2018 for the synthesis of a new 1,5-disubstituted tetrazole

• . Significantly, this protocol enables the rapid and straightforward synthesis of highly 2-substituted indoles with high bond-forming efficiency, creating six new bonds (two C–C, three C–N, and one N–N). Our synthetic strategy would represent the second report in which the Pd/Cu-catalyzed heteroannulation

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• pure propargyltrichlorosilane, it clearly demonstrated that this class of chiral Lewis bases regiospecifically catalyzed the addition of propargyltrichlorosilane to aldehydes, and that these catalysts did not induce the propargyl–allenyl metallotropic rearrangement albeit activating the C–Si bond. Thus

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• intersystem crossing (ISC), internal conversion (IC), or quenching by structural relaxation, etc. Finally, the half-life, t1/2, of the quadricyclane derivatives 2h–l,n was determined by kinetic analysis of the thermally induced cycloreversion to the corresponding norbornadiene derivatives 1h–l,n at 60 °C

• bis- and tris-norbornadienyl-substituted benzene derivatives. Photometric monitoring of the irradiation of 1h (A), 1i (B), 1j (C), 1k (D), 1l (E), and 1n (F); λex = 315 nm (1h, 1i, 1k, and 1l) or 340 nm (1j, 1n). Insets: plot of absorption at long-wavelength maximum versus irradiation time t

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• of an NRP despite the fact that this feature is known to be important for bioactivity [79][80]. Typically, the C-terminus of the NRP intermediate is covalently linked via a thioester bond to the phosphopantetheine prosthetic arm of the peptide carrier protein (also known as the thiolation (T) domain

• based on a dataset of known pairs of nonribosomal code/substrate BB. c) An analysis that compared the known vs predicted NRP BBs grouped based on their chemical structures found both oversampled (green)/underexplored (blue) niches in the NRP chemical space; the analysis was performed across all bacteria

• (overall) and for the top four most common phyla (Actinobacteria (A), Proteobacteria (P), Cyanobacteria (C), Firmicutes (F), and others (O)). d) and e) are the most oversampled and underexplored groups of NRP BBs, respectively. Syn-BNPs were synthesized in accordance to predicted NRP structures; shown

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• rigidity along the C–C bond between the heterocycle and ethene bridge due to the fused cyclic fragment. As a consequence of the additional ring, the fluorescence efficiency increased. At the same time, solid-state emission was observed due to the steric hindrance, which prevented intermolecular

• ,1H-NOESY spectrum of compound 1c in DMSO-d6. Absorption (left) and normalized emission spectra (right) of compound 1i in various solvents (c = 10−5 M). Solvatochromic behavior of compounds 1c and 1i: plots of arithmetic mean of emission/absorption wavenumbers vs Kawsk–Chamma–Viallet polarity function

• (left) and photos of fluorescent solutions in various solvents taken under a 365 nm UV lamp (right). Absorption spectra of compounds 1a–i in toluene (left) and DMSO (right, c = 10−5 M). Normalized emission spectra of compounds 1a–i in toluene (left) and DMSO (right, c = 10−5 M). Photos of fluorescent