Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• , the aromatic protons of the added phenyl ring appear as a typical coupling pattern in the expected range for phenyl ethers. The acetyl-methyl group is shifted by 0.3 ppm to a higher field and the methyl group in position 9 resonates at the same field strength as in the case of 2-iodomelifolione A (8

• group and the center of the multiplet for the axial H-5 lie exactly on the top of each other at 1.61 ppm. The same applies to the signals of both axial H-7 and H-8 at 1.57 ppm. The signal for H-8a appears as a nearly symmetrical quintet, resulting from the trans diaxial coupling with H-8ax (about 10 Hz

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• storage. The target compound was readily synthesized by a Suzuki–Miyaura coupling reaction and examined with respect to the key properties for MOST applications. Upon direct or photosensitized irradiation, the trisnorbornadiene was transformed stepwise and almost quantitatively into the corresponding

• trisnorbornadiene 1f was synthesized in 36% yield through a Suzuki–Miyaura coupling reaction of tribromotrifluorobenzene 3 with the 2-borononorbornadiene 1e (Scheme 2) [43]. The product 1f was identified and fully characterized by NMR spectroscopy (1H, 13C, 19F, COSY, HSQC, HMBC), mass spectrometry, melting point

• Information File 1, Figure S16). Contrary to the 1H NMR spectra, the 19F NMR spectra showed significantly fewer signals (one or two per molecule) during the photoreaction because of the symmetry of norbornadiene 1f and its photoproducts and the less complex coupling pattern. Thus, the 19F NMR spectra of the

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• –Kishi (NHK) coupling and Pd-mediated cyclization. Fragment 31 was synthesized from known precursor 28 [74] in 9 steps via MMTr-protection, replacement of the Bn- with TBDMS-protecting groups, hydroxylation of sulfone 29 to alcohol 30, tosylation, bromide substitution, acidic MMTr-cleavage and DMP

• -oxidation (Scheme 4, above). For the assembly of 33, only the hydrolysis of previously reported 32 [75] with Me3SnOH and thioesterification using EtSH and DCC were necessary (Scheme 4, below). Both fragments (31 and 33) were fused together via NHK coupling to furnish 34 in 86% yield. The addition of SrCO3

• proved to be suitable for the cyclization towards 35 and the eventual macrocyclization was achieved via coupling of the alkyl bromide unit with the thioester. Mechanistically, this reaction is enabled by the formation of an intermediate alkylzinc halide, which is produced by single electron transfer

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• carboxylic acid derivatives such as esters, acyl chlorides and anhydrides with hydroxylamine salts [41]. A variety of coupling or activating agents were also employed in case of simple addition of hydroxylamine to carboxylic acid compounds [42][43][44]. In addition, alternative methods starting from

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• , Hayashizaki, and Ito reported a highly stereoselective asymmetric cross-coupling reaction of 2-methylnaphthylmagnesium bromide with bromonaphthalene, catalyzed by a nickel complex with ferrocenylphosphine as the ligand, successfully synthesizing biaxially chiral molecules, namely 1,1':5',1"- and 1,1':4',1

• [2 + 2 + 2] cycloaddition reaction between α,ω-diynes 1 and monoalkynes 2, providing an alternative to traditional asymmetric coupling strategies for the synthesis of C2-symmetric biaryl chiral compounds (Scheme 1a) [40]. They further demonstrated the feasibility of constructing N-, O-, and C

• studies have further broadened the synthetic toolbox for remote biaxial chirality. Du and co-workers designed a series of chiral phosphoric acid catalysts derived from protected axially chiral diols 13, employing a boronic acid-mediated coupling strategy to construct remote biaxially chiral phosphoric

Synthesis and stereochemical analysis of dynamic planar chiral oxa[7]orthocyclophene

• Yukiho Hashimoto,
• Yuuya Kawasaki,
• Kazunobu Igawa and
• Katsuhiko Tomooka

Beilstein J. Org. Chem. 2026, 22, 436–442, doi:10.3762/bjoc.22.30

• Advanced Science and Technology, Kumamoto University, Kurokami, Kumamoto 865-8555, Japan 10.3762/bjoc.22.30 Abstract Planar chiral C6-substituted oxa[7]orthocyclophenes were designed and synthesized, and their stereochemical behavior was analyzed. The Kumada–Tamao coupling of the C6-iodo-substituted

• -substituted oxacyclophenes 1ab (X = O, Y = Me), 1ac (X = O, Y = Ph), and 1ad (X = O, Y = I), in which 1ad was used as the key intermediate for the synthesis of 1ab and 1ac via Kumada–Tamao coupling with Grignard reagents (Figure 2). Results and Discussion Retrosynthesis and synthesis of the C6-iodo

• coupling of compound 1ad with MeMgBr and PhMgBr in the presence of a catalytic amount of NiCl2(PPh3)2 proceeded smoothly to provide the C6-methyl-substituted 1ab in 79% yield and the C6-phenyl-substituted 1ac in 99% yield (Scheme 3) [15][16]. Suitable single crystals were obtained from racemic 1ac, and its

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• ), multiplet (m), quintet (quint) and other symbols are used to represent signal multiplicities, and Hz is used to denote the coupling constants (J). The spectra were compared to residual solvent peaks or TMS (CDCl₃: 1H, δ = 7.26 ppm; 13C, δ = 77.36 ppm). A Bruker D8 Quest diffractometer was used to obtain

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• important functionalities which can be introduced into calix[4]arene structures either through a wide-rim exhaustive nitration followed by reduction of the nitro groups [5][6][7][8][9][10][11][12][13], or through azo coupling followed by cleavage of the calixarene azo compounds thus formed [14][15][16][17

• ]arene. Notably, the alternative strategy of utilizing an azo coupling/cleavage sequence has only been applied thus far for the wide-rim modification of narrow-rim unsubstituted calixarenes. Since the exhaustive nitration and reduction steps proceed under relatively drastic conditions, which are poorly

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• is often hindered by chemoselectivity and regioselective control. Here, we exploit the differential redox potentials of two coupling partners as a key player to achieve a chemo- and regioselective electrosynthetic access to a new family of unsymmetrical oxaza[8]helicenes. A controlled anodic sequence

• enables selective oxidative hetero-coupling followed by dehydrative cyclization, furnishing the extended [8]helical scaffold efficiently under mild, oxidant-free conditions. Structural analyses show retained aromaticity, increased helical distortion, and higher configurational stability (≈38 kcal/mol

• Supporting Information File 1), we developed a one-pot electrochemical annulation between 3 and β-naphthol derivative 4. Using n-Bu4NPF6 as the electrolyte in CH2Cl2 at room temperature, this protocol furnished oxaza[8]helicenes 5 in good-to-moderate yields with >75% Faradaic efficiency, and no homo-coupling

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• effective esterification of amides using dimethyl sulfate (Me2SO4) as a cheap and powerful coupling reagent (Scheme 11) [59]. In the presence of 1 equivalent of Me2SO4 at 120 °C, secondary N-benzyl benzamide (52) underwent direct esterification with butanol to afford butyl benzoate (51) in 92% yield. When N

• -transfer (SET)-driven mechanism. Coordination of the arylamine to the potassium cation followed by deprotonation generates potassium amide salt AB. A SET process forms amine radical AC, which then transfers an electron to the amide, generating radical anion AD. Coupling of AC and AD forms a tetrahedral

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• propargylamines via A3-coupling reaction [21]. In analogy to a literature procedure [22], heating of radical 2a in a mixture of dimethylamine, formalin, and tetrahydrofuran in the presence of copper(II) acetate afforded the corresponding dimethylamino derivative 2f. To confirm the structure of the novel

• benzoylation of hydroxymethyl groups under the conditions of Sonogashira cross-coupling, nitroxide 2a was treated with acetic anhydride in the presence of sodium acetate, yielding the diacyl derivative 5. Radicals 5 and 3a were heated with benzoyl chloride and triethylamine in toluene in the presence of a

• CD3OD. The full spectral line shapes were simulated using the gNMR program to assign the signals and to obtain the coupling constants [33]. Direct comparison of the spin–spin coupling constants within the six-spin systems of the non-annulated nitroxide 9a with its annulated counterparts 9b,c revealed

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• deshielding effect of the directly attached nitrogen atom on the CH21 group. The methine protons resonate as distinct signals appearing as a ddd for CH4, dd for CH5, and a d for CH6. Chemical shift values, signal multiplicities, and spin–spin coupling constants for the methine protons of all compounds are

• were established using 1H,13C HSQC NMR spectroscopy. The chemical shift values, signal shapes, and spin–spin coupling constants are provided in Table S1 in Supporting Information File 1. The aromatic protons of compounds 4c–e appear in the downfield region of the spectrum. For product 4c, the aromatic

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• architecturally complex, three-dimensional molecular frameworks from simple arene precursors (Figure 9). A major conceptual milestone was achieved by Yamamoto and co-workers in 2001, who unveiled the first dearomatization of benzyl chlorides with allyltributylstannane under Stille coupling conditions (Scheme 6A

• process. Subsequent computational studies, however, refined this mechanistic understanding, revealing that reductive elimination proceeds through coupling of the C(3) terminus of the η1-allyl fragment with the para-carbon of the η3-benzyl ligand (Scheme 6A, right) [75]. Together, these insights

• transformation of allyl chloride-substituted naphthalenes and phenanthrenes in the selective coupling with allylstannanes to deliver the corresponding ortho-allylated products [84]. Subsequently, Bao and co-workers extended this concept to encompass allenylstannanes, thereby accessing the propargylated analogues

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• states, intermolecular interactions enhance spin–orbit coupling and crystallinity suppresses nonradiative decay, thereby activating RTP. This work achieves an integrated “crystalline-state RTP–amorphous-state TADF” regulation within a single molecule. Keywords: imide; π–π stacking; room-temperature

• phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) [2][12][13][14][15][16][17][18][19]. RTP is a process where the spin-forbidden transition from the triplet state to the ground state becomes observable at room temperature due to the enhancement of spin–orbit coupling (SOC) and suppression

• intermolecular coupling to enhance SOC and suppress non-radiative decay channels, while TADF relies more on donor–acceptor decoupling and smaller ΔEST to lower the thermal activation barrier for RISC. Thus, a key challenge in the field is how to establish adjustable synergy between the molecular-scale

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• ) values are reported in ppm, coupling constants (J) in Hz, and the peak multiplicity is referred to the following abbreviations: bs (broad singlet), s (singlet), d (doublet), t (triplet), q (quartet), p (pentet), sex (sextet), h (heptet), and m (multiplet). To investigate the possible presence of an IMHB

Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling

• Guoling Huang,
• Huarui Zhu,
• Shuting Zhou,
• Wanlin Zheng,
• Fangpeng Liang,
• Zhibo Zhao,
• Yifei Chen and
• Xunbo Lu

Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9

• /bjoc.22.9 Abstract A selective and efficient method for the synthesis of sulfinimidate esters via an NBS-promoted oxidative coupling of sulfenamides with alcohols has been developed. This operationally simple, metal-free protocol uses inexpensive and readily available reagents, operates under mild

• investigated the scope of alcohols in the NBS-promoted coupling with sulfenamides under the optimized conditions (Scheme 4). A series of linear alcohols, including simple aliphatic alcohols such as ethanol, 1-propanol, 1-butanol, and 1-octanol, as well as aromatic-substituted alcohols like 3-phenyl-1-propanol

• , the sulfenamide-based oxidative coupling proceeded smoothly, delivering sulfilimidate ester 4 in 53% yield. In addition, the transformation was applied to a chiral secondary alcohol, ʟ-menthol, to generate the sulfilimidate ester 5 in 67% yield. A diastereomeric analysis revealed a modest dr of 1.6:1

Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• chiral platinum(II) complex was synthesized via Sonogashira coupling and subsequent coordination of a pincer ligand to a precursor. The complex exhibited a broad absorption band ranging from 250 to 550 nm in the UV–vis spectrum, with TD-DFT calculations indicating mixed ligand-to-ligand charge transfer

• two platinum(II) chromophore units, leading to the chiroptical properties in the MLCT region through exciton coupling under restricted molecular motion. Keywords: axial chirality; chiral chemistry; circularly polarized luminescence (CPL); phosphorescence; platinum(II) complex; Introduction

• exciton coupling in both the ground and excited states. While no CPL was observed in solution, distinct CPL properties observed in the PMMA matrices. This behavior is attributed to the effect of the axial chirality, which becomes more effective upon suppression of molecular motion within the polymer

Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection

• Ergin Keleş,
• Alberto Barsella,
• Nurgül Seferoğlu,
• Zeynel Seferoğlu and
• Burcu Aydıner

Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6

• /acetic acid buffers with a good yield (84%). Target compounds were synthesized by a coupling reaction between 2-(1,3-dihydro-2H-inden-2-ylidene)malononitrile (1) and appropriate alkylaminobenzaldehyde derivatives in acetic anhydride. Compounds were obtained with low to good yields (25–75%, conventional

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• )/CH3 (pyrazolone) (δH = 2.15 ppm) in the minor isomer 9b (Scheme 5). Thus, the relative configurations of the stereocenters in these molecules can be defined as 1SR,2RS,3SR (9a) and 1SR,2RS,3RS (9b). Cyclopropanes 2–8 are formed as single diastereomers. The vicinal spin–spin coupling constants of C1H

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• ][19][20]. In recent years, promoted by the rapid development of asymmetric catalysis, a wealth of reactions applicable to aromatic systems – including substitution reactions, transition-metal-coupling reactions, and even dearomatization [21][22][23] – have been reported, further extending their

• ]. Starting from pyridine derivatives 129, they obtained the key intermediate 131 via a Simmon–Smith reaction and a bimetallic-mediated photocatalytic radical coupling reaction. Intermediate 132 was then constructed by Friedel–Crafts alkylation using diethylaluminum chloride as a Lewis acid. The pyridine ring

• , which perfomed as a key substrate for the aerobic oxidation. The formation of the tetracyclic 3-spirooxindole structure 137 was achieved through a transition-metal-free intramolecular cross-dehydrogenative coupling. With 137 in hand, a sequence of transformations including ketone reduction with NaBH4

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• alkyl iodide 10 were subjected to nickel catalysis in the presence of zirconocene dichloride and zinc dust, intermolecular coupling occurred to afford ketone 12 in good yields. This reaction was applicable to substrates bearing β-alkoxy substituents, which are typically problematic under anionic

• suggested that the developed reaction would be applicable to halichondrin synthesis. The Zr/Ni-mediated ketone synthesis was then applied to the total synthesis of homohalichondrin B (58, Scheme 11B). Using a fragment corresponding to homohalichondrin B, the coupling reaction furnished ketone 57 in 82

• ). The developed dimerization protocol proved scalable to 100 g scale, affording 40 g of the desired dimer 61b in 47% yield. Subsequent removal of the two Boc groups with TMSI, followed by HATU-mediated amide coupling with various amino acids 65–67, furnished the diketopiperazine precursors 68–70

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• alkenyl chlorides. The discussion begins with reductive metalation, reactions with organolithium reagents, and eliminations to terminal alkynes – some of which are also exemplified in chapter 1. This is followed by palladium- and nickel-catalyzed cross-coupling reactions. The chapter concludes with a

• previous studies, aliphatic alkynes were found to be inefficient coupling partners under these conditions (compound 238). Sasaki observed that hydrated zinc dichloride enabled the formation of alkenyl chloride 242 upon reaction of silylated alkyne 241 with 1-adamantyl chloride (240) (Scheme 46A) [152

• construction of structurally complex motifs in a concise number of steps. A recent account by Frontier and Hernandez provides a comprehensive and mechanistically summary of halo-Nazarov electrocyclizations [173]. 1.7 Coupling reactions As already mentioned in the introduction, the coupling reaction of 1,1

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• ][31][32][33][34][35] coupling is very limited. In most existing approaches, the N–N and N–O moieties are derived from hydrazine or hydroxylamine synthons, respectively. The development of novel synthetic methodologies based on non-traditional retrosynthetic disconnections offers a potential pathway to

• and N–O bond formation. However, it also represents a highly efficient and valuable strategy due to the synthetic availability of starting materials. Therefore, the development of new methods for direct selective N–N and N–O coupling remains an important goal in synthetic chemistry. To date

• approaches focus mainly on intramolecular radical cyclizations [42][54][55][56][57][58][59][60][61][62][63], while intermolecular [1][64][65][66][67][68] N–N coupling remains a poorly studied area. In addition to the preparation of azo compounds [69][70], intermolecular N–N coupling reactions are of

Total synthesis of asperdinones B, C, D, E and terezine D

• Ravi Devarajappa and
• Stephen Hanessian

Beilstein J. Org. Chem. 2025, 21, 2730–2738, doi:10.3762/bjoc.21.210

• tryptophan were explored. Different approaches were adopted for the functionalization of C4–C7 prenylindoles at C-3 using Negishi cross-coupling methods. The asperdinones are among the rare tryptophan-derived indole alkaloids which appear to have undergone epimerization due to genetic alteration of specific

• transferase AnaPT. A second, less evident approach, starts with a prenylindole, followed by introducing an (R)- or (S)-2-aminopropionate (alanine) unit at C-3 by a Negishi cross-coupling reaction (Figure 2, approach B, D–F). Although each approach has precedents in different contexts, achieving regioselective

• amorphous powder. Viswanathan [25] and Chen [28] reported a C-2 prenylation of tryptophan methyl ester mediated by acid salts and Lewis acids, respectively. A prenylation at C-4 in bis-N-Boc-tryptophan methyl ester has been achieved by Chein utilizing optimized Suzuki coupling conditions [29]. Results and

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• , HMBC experiments. The relative configuration was established based on the analysis of spin–spin coupling constants 3JH,H and 4JH,H as well as on a set of NOE-correlations. Equatorial or pseudo-equatorial protons of the methylene groups in compounds 4 and 5 were identified by the long-range coupling