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

• disulfide F3CS–SCF3 were employed (Scheme 2, 10 examples, up to 76% yield). With this approach, derivatives bearing an aromatic part substituted at the para-position with electron-donating substituents (1a,b), halogens (1c) as well as electron-withdrawing groups (1d) were difunctionalized in good yields

• the presence of an electrophilic source or an oxidation/ligand exchange in the presence of a nucleophilic source (i.e., AgSCF3) and an oxidant (B in Scheme 4). Finally, after a reductive elimination step, the expected functionalized product 6 is obtained and the palladium catalyst is regenerated. In

• ) were found to be suitable substrates leading to the corresponding products 12h and 12i in 91% and 83% yields, respectively. The use of other directing groups was also suitable for this transformation such as methyl and cyano-substituted pyridines 13a,b, pyrimidine (13c), pyrazole (13d), as well as the

Dipeptide analogues of fluorinated aminophosphonic acid sodium salts as moderate competitive inhibitors of cathepsin C

• Karolina Wątroba,
• Małgorzata Pawełczak and
• Marcin Kaźmierczak

Beilstein J. Org. Chem. 2023, 19, 434–439, doi:10.3762/bjoc.19.33

• development of fluorinated aminophosphonate-based inhibitors. Keywords: aminophosphonates; cathepsin C; dipeptide; fluorine; solvolysis; Introduction Cathepsin C, also known as dipeptidyl peptidase I (DPPI) belongs to the family of lysosomal cysteine proteases encompassing 11 human enzymes (cathepsins B, C

• of more effective fluorinated inhibitors of cathepsin C in our laboratory. Dixon plot for the hydrolysis of Gly-Phe-pNA substrate catalyzed by bovine cathepsin C in the presence of 9b (T = 37 °C, pH 5.0). Synthetic strategy towards 5 and 7. Synthesis of 9 and 11. (a) R = -CH3; (b) R = -CH(CH3)2; (c

• ) R = -CH2CH(CH3)2; (d) R = -CH(CH3)CH2CH3, (e) R = -CH2Ph; i) (a) 5 or 7 (1 equiv), TMSBr (8 equiv), CH2Cl2, rt, 20 h, (b) MeOH, 30 min.; ii) 8 or 10 (1 equiv), 1 M NaOH (2 equiv), H2O, 15 min. The 13C NMR chemical shifts of C1 and C2 carbon atoms. Inhibitory constants of the studied of α- and β

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

• of an unsaturated fourteen- or sixteen-membered macrolactone decorated by an ʟ-cysteine-derived 2-oxo-1,3-thiazolidin-4-yl substitutent, and the presence of five stereogenic centers forming a 1,2,4,6,9-stereopentade (Figure 1). In latrunculins A (1) and B (2) three of them are embedded in a lactol

• ring, while latrunculin C (3) lacks this ring due to the reduction of C-15. The biological activities of latrunculins A and B have early been reported [3]. These compounds induce important but reversible morphological changes on mouse neuroblastoma and fibroblast cells at low concentrations such as 50

• (13,14)-bond of 1 and 2, respectively. Conversely, we envisaged an alternative disconnection to form the (16,17)- or the (14,15)-bond of 1 and 2, through an aldol reaction of aldehyde 8 readily available from ʟ-cysteine, leading to aldol adduct 7 (Figure 2, route B). The methyl ketone partner 9 could be

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• quantities for the evaluation of biological/pharmacological activities. Review 1 Isolation 1.1 Isolation of combretastatins D series Combretastatins comprise a large family of structurally diverse natural products divided into the “A” (cis-stilbenes), “B” (dehydrostilbenes), “C” (phenanthrenes), and “D

• was used to isolate the known compound corniculatolide A (4, 10 mg) as colorless crystals [14]. Later the same group reported the isolation of corniculatolide B (9), isocorniculatolide B (10), and corniculatolide C (11) from Xylocarpus granatum, a tree commonly found in Southeast Asia and along the

• hexane/acetone/MeOH to 20% MeOH. From the six main fractions, three of them showed the new structures, corniculatolide B (9, 3 mg), isocorniculatolide B (10, 2 mg), and corniculatolide C (11, 5 mg), among some other known constituents. Different 1H and 13C NMR and HRESIMS techniques were employed to

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• -cyclodextrin from the secondary face; (b) glyceryl 1,2-oleate 3-palmitate from hazelnut oil interacts with the β-cyclodextrin from the primary face, while silibinin A, the main component of silymarin, interacts with β-cyclodextrin from the secondary face. Superposition of the FTIR spectra for the β

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• chemistry” was introduced for the first time by K. B. Sharpless in 1999 at the 217th ACS annual meeting [4]. Most recently, K. B. Sharpless shared the 2022 Nobel Prize in Chemistry with C. R. Bertozzi and M. Meldal for the development of click chemistry and bioorthogonal chemistry. Due to high product

• subunits. Bryden and Boyle [29] presented a mild and facile one-pot synthesis of meso-substituted zinc(II) azido-porphyrin 39a–c in excellent yield by using a diazo-transfer reagent and utilized it for the preparation of 1,2,3-triazole-linked porphyrin conjugates 40a,b using copper(I)-catalyzed click

• reactions (Scheme 6). The authors selected the hydrogen sulfate salt of imidazole-1-sulfonyl-azide for the formation of azide porphyrins 39a–c due to its greater shock stability and storage than its HCl salt. After the successful preparation of the zinc triazoloporphyrins 40a,b, their corresponding free

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

• -catalysed hydroboration of alkynes was first reported by Periasamy using N,N-diethylaniline·BH3 as the catalyst and HBcat as the turnover reagent (terminal reductant) [48][49]. This was followed by Hoshi who used dialkylboranes, 9-borabicyclo(3.3.1)nonane (H-B-9-BBN) and dicyclohexylborane (Cy2BH) to

• -trifluorophenyl)borane [54], BH3 [55][56][57], and H-B-9-BBN [58] have also been reported as catalysts for the hydroboration of alkynes with HBpin (Scheme 2). Lloyd-Jones et al. investigated the mechanism of this reaction and found transborylation, group 13 exchange between boron atoms, enabled catalytic turnover

• [58]. The alkyne 1 and dialkylborane reacted to give an alkenylborane 2. Transborylation with HBpin gave the alkenyl boronic ester 3 and regenerated the catalyst, HBR2. Isotopic labelling (H10Bpin) confirmed B–C(sp2)/B–H transborylation proceeded by σ-bond metathesis, and not ligand exchange. Using

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• electron-rich salt 5al was obtained in 75% yield using modified reaction conditions B. The harsher conditions were probably required due to a sterically hindered rotation of the benzimidazole moiety in the plane of the iodophenyl, which could also be observed in two rotamers of the starting iodoarene 4al

• (200 µmol) and mCPBA (1.1 equiv) were dissolved/suspended in DCM (1 mL), TfOH (2.5 equiv) was added, and the reaction mixture was stirred for 72 h at 40 °C. Method B: Iodoarene 4 (200 µmol) and mCPBA (1.3 equiv) were dissolved/suspended in DCM (1 mL), TfOH (5.0 equiv) was added, and the reaction

• –O5: 2.898 Å, C8–I1–O1: 173.80°, C6–I1–O5: 167.75°, C6–I1–C8: 94.05°; for 5ax: I1–O3: 3.354 Å, I1–O5, 3.078 Å, C1–I1–O3: 154.71°, C8–I1–O5: 148.91°, C1–I1–C8: 94.53°. Derivatizations of the iodonium salt 5aa. a) Ac2O, CuSO4·5H2O, NaOAc, AcOH, 120 °C, 5 h; b) S8/Se/Te, Cs2CO3, DMSO, rt–100 °C, 2.5–24 h

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

• Robert N. Goldberg,
• Robert T. Giessmann,
• Peter J. Halling,
• Carsten Kettner and
• Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

• ), zi is the charge number of ion i, and B is a constant which is often referred to as the “ion-size” parameter. Alberty et al. [10] used the value B = 1.6 kg1/2∙mol−1/2 based on the values of this parameter obtained in fitting data on a series of electrolytes of charge type 1-1, 1-2, and 2-1 [23]. The

• side reactions. As above, if the enzyme loses activity before the reaction reaches equilibrium, QF ≠ QR. If the enzyme remains active, QF will be equal to QR within the measurement uncertainties and K will be equal to , where the <> indicate the average of the values of QF and QR. B. There are side

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

• Martin Kalník,
• Sergej Šesták,
• Juraj Kóňa,
• Maroš Bella and
• Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

• ) between the N-2-naphthylmethyl moiety of the inhibitors 28 and 31 and the active-site amino acid residues of dGMII. The most significant ΔElinker-E are marked. Synthesis of the key pyrrolidine 3 and the target pyrrolidines 7–10. Reagents and conditions: (a) MsCl, Et3N, CH2Cl2, 0 °C–rt, overnight, 80%; (b

• .; (h) 1. H2, Pd/C, MeOH, rt, 2 h; 2. conc. HCl, 0–40 °C, 2 h, 68%. Synthesis of the intermediate 13 and the target pyrrolidines 17–20. Reagents and conditions: (a) 1. H2, Pd/C, MeOH, rt, 48 h; 2. CbzCl, Et3N, CH2Cl2, 0 °C–rt, 2 h, 91% over two steps, (b) PTSA·H2O, CH2Cl2/MeOH 30:1, rt, 20 min, 90%; (c

• conditions: (a) Tf2O, pyridine, CH2Cl2, 0 °C, 1.5 h, 64%; (b) 10% aq NaOH, EtOH, reflux, 24 h, 67%; (c) ArCH2Br, K2CO3, DMF, 0 °C–rt, overnight; (d) 20% HCl, MeOH, rt, 72 h; (e) H2, Pd/C, MeOH, rt, 5 h, then, conc. HCl, 0 °C, 86%. Inhibition (IC50, Ki values and selectivity index, SI) of class II GH38 α

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• standing out. The first one (strategy 1, Figure 3) consists in the successive formation of the eight-membered ring B followed by construction of the five-membered ring C: i.e., the cyclooctene ring is built first from a suitably substituted cyclopentane substrate, which then serves as a precursor for the

• cyclopentane ring C formation. In the second strategy (strategy 2, Figure 3), both cyclopentane rings A and C are formed first, and the eight-membered ring B is introduced at a late stage. 1.1.1.1 Strategy 1: Successive introduction of rings B and C starting from cyclopentene via the [5-8] bicyclic structure

• 14 shares the common [5-8-5] tricyclic framework emblematic of the fusicoccan series, albeit cycloaraneosene (14) does not have any heteroatom (Scheme 1) [16]. Focusing on the B–C bicyclic fragment, they used diene 10, readily available from cyclopentane-1,3-dione (9), as the precursor for installing

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• Shubham Sharma Dharmender Singh Sunit Kumar Vaishali Rahul Jamra Naveen Banyal Deepika Chandi C. Malakar Virender Singh Department of Chemistry, Dr B R Ambedkar National Institute of Technology (NIT) Jalandhar, 144027, Punjab, India Central Revenues Control Laboratory, New Delhi-110012, India

• 11 and 12 were also tolerated well for this thioamidation process and furnished the anticipated products 11A,B,E, and 12C in good to excellent yields (58–92%) within 40 min to 4 hours. To check the industrial scope of the current protocol, we conducted a gram-scale reaction between pyrazole-3

• . The multiplicity in the 13C NMR spectra is presented as d for doublet. Experimental procedures General procedure for the synthesis of compounds 1A–E, 2–4C, 5A–E, 6–8C, 9C, 10A, 11A,B, 11E, and 12C as exemplified for (5-(4-fluorophenyl)-1-phenyl-1H-pyrazol-3-yl)(morpholino)methanethione (1C): In a dry

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• rapidly turned yellow, which is another sign of undesired side reactions. Besides, 1H NMR spectra of the obtained polymers during the polymerization process (Figure S1 in Supporting Information File 1) demonstrate the appearance of new signals at 1.65 ppm (box a), 2.84 ppm (box b), 3.20 (box c), 3.82 ppm

• capacity of PEtOx25-b-PBuOx30-b-PEtOx25 and PMeOx25-b-PBuOx30-b-PMeOx25 [52]. Since the MeOx polymerization did not show positive results but EtOx polymerization did work to some extent, we performed a preliminary test for chain extension and to synthesize triblock copolymers. EtOxMeOTf was used to

• observed after 3 h of reaction) during polymerization at 90 °C, but the final molar mass remains lower than expected with significant bimodality. An attempt at the synthesis of a PEtOx-b-PBuOx-b-PEtOx triblock copolymer yielded again a broad molar mass distribution and a lower molar mass than expected by

An accelerated Rauhut–Currier dimerization enabled the synthesis of (±)-incarvilleatone and anticancer studies

• Tharun K. Kotammagari,
• Sweta Misra,
• Sayantan Paul,
• Sunita Kunte,
• Rajesh G. Gonnade,
• Manas K. Santra and
• Asish K. Bhattacharya

Beilstein J. Org. Chem. 2023, 19, 204–211, doi:10.3762/bjoc.19.19

• followed by an intermolecular conjugate addition to form a C–C bond (path A). In an alternative approach (path B) first I undergoes a nucleophilic conjugate addition in intermolecular fashion to give intermediate III and followed by an intramolecular addition to give compound IV. In both paths, the

• intermediate A tetrahydrofuran intermediate B with cis-fused ring systems is formed as seen in the existing literature [7]. A proton transfer of enolate moiety B yields another enolate C followed by the β-alkoxy elimination [17] of intermediate C to form intermediate D. The intermediate D on protonation leads

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

• potentially arise from the achiral sesquiterpene hydrocarbon germacrene B. Not only compounds isolated from natural sources, but also synthetic compounds are dicussed, with the aim to give a rationale for the structural assignment for each compound. A total number of 64 compounds is presented, with 131 cited

• references. Keywords: biosynthesis; configuration determination; germacrene B; structure elucidation; terpenes; Introduction Terpenoids constitute the largest class of natural products with ca. 100,000 known compounds. Biosynthetically, all terpenoids are derived from only a few acyclic precursors

• cation (B) or a 1,11-cyclisation to the (E,E)-humulyl cation (C) is possible. Reattack of diphosphate at C-3 results in nerolidyl diphosphate (NPP) that can undergo a conformational change by rotation around the C-2/C-3 single bond, which allows reionisation to D. This intermediate can react in a 1,10

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

• Benedikt Kolb,
• Daniela Silva dos Santos,
• Sanja Krause,
• Anna Zens and
• Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

• with Schwartz's reagent and our work [54][55][57][58][61][62]. Synthesis of substituted enynes 25f–o via Corey–Fuchs reaction and Hunsdiecker reaction. Synthesis of non-natural (a) and natural (b) dienone-containing terpenes: synthesis of β-ionone (3). Synthesis of enynes 25 via Corey–Fuchs reaction

Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris

• Angelique Ladwig,
• Markus Kroll and
• Stefan Schulz

Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16

• species for the investigation of the gular gland compound composition of hyperolids. The macrolides (Z)-tetradec-5-en-13-olide (D) [4], frogolide (E) [5], and cinnamomeoventrolide (B) [6] have been identified in earlier works as gular gland constituents of this species (Figure 2). Macrolides are commonly

• identified in gular glands of male Hyperolius cinnamomeoventris. Total ion chromatogram (TIC) of a gular gland extract of Hyperolius cinnamomeoventris on a polar DB-wax GC phase. A, C: sesquiterpenes; B: cinnamomeoventrolide; D: (Z)-tetradec-5-en-13-olide; E: frogolide. Mass spectrum of sesquiterpene A (I

• Hydrodex β-6TBDM column. Compound B serves as relative standard to target compound A. Mass spectra of each cadinol-type diastereomer. The box colors refer to the peaks and compounds in Figure 5. Racemic synthesis of cadinols modified from Taber and Gunn [13]. Conditions a) i) K2CO3 (0.35 equiv), 0 °C, 1 h

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

• -chestnut leaf miner) and reported retrosynthetic pathways. a) Alkyl–vinyl seminal cross-coupling reaction by Kochi; b) improved procedure described by Cahiez. Iron-catalyzed cross-coupling of n-OctMgCl with a 1-butadienyl phosphate. Synthesis of several insect sex pheromones (a) red bollworm moth, b

• ) European grapevine moth, c) horse-chestnut leaf miner) involving a key alkyl–alkenyl iron-mediated cross-coupling between a dienol phosphate and an α,ω-difunctionalized Grignard reagent. Cross-coupling of alkyl Grignard reagents with a) alkenyl or b) aryl halides involving EtOMgCl as additive. Total

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

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

• Naoya Oku,
• Saki Hayashi,
• Yuji Yamaguchi,
• Hiroyuki Takenaka and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

• , antifoamers, preservatives, antistatic agents, polymer lubricants, and mold-releasing agents for the production of foods, cosmetics, ointments, paints, and plastics [33]. Compound 1 exhibited antibacterial activity, evaluated by a microculture method, with MIC 50 μg/mL against B. subtilis ATCC6633 and 100 μg

• /mL against S. aureus FDA209P JC-1 (Table 2). Congener 3b, having a two-carbon-longer alkyl chain, was equally potent against S. aureus but was less active against B. subtilis than compound 1. Interestingly, sn-3 linoleate 3b was more potent than its antipode 3a. Experimental General methods Cosmosil

• mM NaClO4 30:70, 45:55, 60:40, 75:25, 90:10, and chloroform/MeOH/H2O 6:4:1 to give six fractions. Antibacterial activity against S. aureus FDA209P JC-1 and B. subtilis ATCC6633 was detected with the second and fourth fractions. The latter was gel-filtered on Sephadex LH-20 (MeCN/50 mM NaClO4 75:25

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• extensively explored, is in asymmetric synthesis, although this should be quite feasible. We hope this review can help inspire such future developments. a) 1,4-Dithiane-type building blocks that can serve as C2-synthons and b) examples of complex target structures that have been prepared using 1,4-dithiane

• ] and b) recent applications in the total synthesis of complex target products (original attachment place of 1,3-dithiane ‘scaffolding’ groups shown with dashed purple lines) [7][8][9][10][11]. Metalation of other saturated heterocycles is often problematic due to β-elimination [16][17]. Thianes as

Practical synthesis of isocoumarins via Rh(III)-catalyzed C–H activation/annulation cascade

• Qian-Ci Gao,
• Yi-Fei Li,
• Jun Xuan and
• Xiao-Qiang Hu

Beilstein J. Org. Chem. 2023, 19, 100–106, doi:10.3762/bjoc.19.10

• active Rh catalyst. Subsequently, the oxygen atom of the enaminone is coordinated to the Rh catalyst, following by a Rh(III)-promoted ortho C–H activation to form a five-membered ruthenacycle 1-A. Then, the reaction of the iodonium ylide with intermediate 1-A generates a Rh-carbenoid intermediate 1-B

• heating module was used for the preparation of isocoumarin products 3.) Significance of isocoumarins (a), classic methods for the synthesis of isocoumarins (b) and reaction design (c). Scope of enaminones. Scope of iodonium ylides. Gram-scale reaction (a) and synthetic transformation (b). Proposed

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• formation of 7 and (b) investigation of the reaction between imine 5a and ester 36. (a) Preparation of acyl chlorides 6ba and 6bb in diastereomerically pure forms, (b) aza-Nazarov cyclization of (E)-6ba and (Z)-6bb under the optimized reaction conditions and (c) tentative mechanism for the olefin E–Z

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• instance, two of the highest field experimental chemical shifts are listed in the Latypov report [37] as −162.6 ppm for (H2P)2PH and −203.6 ppm for (H2P)2 [59]. Problems include (a) the Latypov group did not specify whether the PH or PH2 moiety is the one exhibiting the peak at −162.6 ppm in (H2P)2PH, (b

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

• coupling to 13, 20, 25, and 28, few steps away from the total syntheses of sesquicillin A (18), subglutinols A and B (19 and 24) and higginsianin A (23, Scheme 2). Merged chemoenzymatic and radical synthesis of oxidized pyrone meroterpenoids (Renata 2020) [29]: In 2020, a different approach was

• to synthesize more than 4 g of the natural product (+)-yahazunol (61). (+)-Yahazunol (61) can be readily transformed to several members of meroterpenoids of the class, either by Friedel−Crafts reactions or common oxidative manipulations. Total synthesis of dysideanone B (75) and dysiherbol A (79) (Lu

• 2021) [37]: Dysideanone B (75), isolated from the South China Sea sponge Dysidea avara, possesses an unprecedented 6/6/6/6-fused tetracycle with interesting anticancer properties against HeLa and HepG2 cancer cell lines (Scheme 6) [38]. The structurally similar dysiherbols 79 and 80, bearing a 6/6/5/6