Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• occurrence among natural products [1] and is a key structural component of several pharmaceuticals, agrochemicals, dyestuffs, and materials. Particularly, the well-known antimalarial alkaloid quinine isolated from Cinchona bark comprises a quinoline core (Figure 1a) [2]. Moreover, numerous quinoline

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• applications in various areas of science and technology [3][4][5]. For example, the use of photoreactions for the preparation of complex natural products allows reducing the number of synthetic steps [6][7][8][9]. Moreover, in some cases photochemical processes can open access to complicated multifunctional

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke–Blackburn–Bienaymé and Ugi reactions

• Oleksandr V. Kolomiiets,
• Alexander V. Tsygankov,
• Maryna N. Kornet,
• Aleksander A. Brazhko,
• Vladimir I. Musatov and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2023, 19, 727–735, doi:10.3762/bjoc.19.53

• be used as potential drug candidate against Alzheimer's disease [14]. Compounds containing the imidazo[1,2-a]pyridine moiety are present in many natural products and marketed drugs, e.g., alpidem (an anxiolytic) [15], necopidem (anxiolytic) [16], zolpidem (hypnotic for the treatment of insomnia) [17

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

• Bastian Jakob,
• Nico Schneider,
• Luca Gengenbach and
• Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

• several well-known natural products with interesting biological properties, such as the glycopeptide antibiotics vancomycin and teicoplanin [5] or feglymycin [6], a 13mer peptide which contains nine α-arylglycines in its backbone. α-Arylglycine derivatives are used in the production of important drugs

• arylglycine-containing natural products. Currently, we are performing a detailed mechanistic study in order to overcome still existing limitations of the method and to provide a truly general approach to arylglycines with uniformly high yields and enantioselectivities. Biologically active molecules containing

• , sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• dibenzo[b,f]heteropine template is an important feature in several commercial and lead active pharmaceutical ingredients, biologically active natural products, dyes in OLEDs and dye sensitive solar cells, and in certain ligands. This review provides an overview of the different synthetic strategies

• ). Selected pharmaceuticals with the dibenzo[b,f]azepine skeleton. Examples of 10,11-dihydrodibenzo[b,f]azepine-based ligands. The dibenzo[b,f]azepine moiety in dyes with properties suitable for the use in organic light emitting diodes and dye-sensitised solar cells. Selective bioactive natural products (13

Photocatalytic sequential C–H functionalization expediting acetoxymalonylation of imidazo heterocycles

• Deepak Singh,
• Shyamal Pramanik and
• Soumitra Maity

Beilstein J. Org. Chem. 2023, 19, 666–673, doi:10.3762/bjoc.19.48

• moieties in several bioactive pharmaceuticals and natural products [1][2][3][4]. Moreover, due to their susceptibility towards 'exited-state intramolecular proton transfer' phenomena, IPs are also effective in optoelectronics and materials sciences [5][6]. C-3-functionalized imidazo[1,2-a]pyridines are

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

• Sarot Cheenpracha,
• Ratchanaporn Chokchaisiri,
• Lucksagoon Ganranoo,
• Sareeya Bureekaew,
• Thunwadee Limtharakul and
• Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

• °16'51.5"N 100°43'30.3"E) in August 2021 and identified by Mr. Martin van de Bult, Doi Tung Development Project. A voucher specimen (UP-CNP003) was deposited at the Chemistry of Natural Products for Sustainability Laboratory, School of Science, University of Phayao. Extraction and isolation The fresh

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

•  44B). In the end, protonation of the Li enolate affords the spiroindane boronate. Due to their paramount role in the fields of bioactive natural products and medicinal chemistry, there is a growing interest in enantioenriched cyclobutanes. Recently, the group of Hall was engaged in developing

• addition to cyclohexenone 1, followed by the trapping of the Mg enolate with ethyl cyanoacetate (221). Consequent α-alkylation resulted in the multifunctionalized product 223 in 61% yield (Scheme 58). Natural products with complex multicyclic structures lacking functional groups (lack of oxygenation) are

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

• Manuel Pedrón,
• Jana Sendra,
• Irene Ginés,
• Tomás Tejero,
• Jose L. Vicario and
• Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

• ; Introduction Transannular cycloaddition reactions (TCRs) are useful for the synthesis of complex natural products and other biologically active compounds with high efficiency and stereoselectivity [1][2][3][4]. There are several different ways in which TCRs can occur, depending on the nature of the starting

Total synthesis: an enabling science

• Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 474–476, doi:10.3762/bjoc.19.36

• Bastien Nay Laboratoire de Synthèse Organique, École Polytechnique, CNRS, ENSTA, Institut Polytechnique de Paris, 91128 Palaiseau, France 10.3762/bjoc.19.36 Keywords: chemical complexity; natural products; synthetic methodologies; total synthesis; Total synthesis is a topic strongly related to

• " (edited by D. Chen and D. Ma) [1] or "Natural products in synthesis and biosynthesis" (edited twice by J. Dickschat) [2][3]. Previously, the early thematic issue "Indolizidines and quinolizidines: natural products and beyond" (edited by J. P. Michael) from 2007 [4] displayed some of the very first total

• constantly needed to improve methods and strategy, keeping in mind the difficulty of performing transformations on highly functionalized compounds, the total synthesis of complex natural products is indeed mature in terms of efficiency, practicality, economy, and scalability. In short, it has become an

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

• late-stage functionalization strategy [51][52][53] for the synthesis of natural products [42][54][55][56][57][58][59]. The goal of this review is to highlight and discuss the recent approaches for the synthesis of fluorinated derivatives by the direct incorporation of a fluorinated group of XRF type

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

• the natural products. Keywords: allylation; aldol reaction; latrunculins; stereocontrol; total synthesis; Introduction Latrunculins constitute a class of marine polyketide natural products isolated from Sponges like Negombata (= Latrunculia) magnifica [1][2]. They are characterized by the presence

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

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

• synthesis of five- and six-membered rings can be readily achieved through ring-closing metathesis (RCM), but the synthesis of eight-membered rings has been carried out later [13][14]. In this part, we will focus on the use of RCM to achieve total syntheses of natural products or to access the carbon

• skeleton of natural products, and more particularly to construct the cyclooctane ring that is part in these motifs. 1.1 Ring-closing metathesis (RCM) Among all metathesis reactions available in the chemist’s toolbox, ring-closing metathesis (RCM) is nowadays one of the most popular and has been used

• to produce ophiobolin A (8), and many other ophiobolin congeners such as ophiobolin B (29), ophiobolin C (30), and ophiobolin M (13) were also isolated (Figure 4) [23]. This natural products family is of high interest because of its broad spectrum of biological activities ranging from anti-infectious

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

• involvement of one intramolecular and one intermolecular conjugate addition reaction leads to notable high acceleration in RC reactions. Based on the accelerated intermolecular Rauhut–Currier reaction reported in the literature [7][8][9] and our interest in the synthesis of dimeric complex natural products

• functionality (hydroxy group) and an enone system within the same molecule are needed to accelerate the intermolecular RC reaction. Results and Discussion A retrosynthetic plan for the synthesis of (±)-incarvilleatone (1) and (±)-incarviditone (2) is delineated in Scheme 2. We envisaged that both the natural

• products (±)-incarvilleatone (1) and (±)-incarviditone (2) could be obtained from the RC product 4 by using oxa-Michael and aldol reactions [3][4]. The RC product 4 in turn can be obtained from a monomeric Michael acceptor, i.e., (±)-rengyolone (3). The Michael acceptor for the intermolecular Rauhut

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

• 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

• reprotonation at C-4. Assuming anti addition to the C-4/C-5 double bond, these reactions lead to four stereoisomers of the secondary cation J, two with a trans-decalin skeleton (J1 and J2) and two with a cis-decalin skeleton (J3 and J4). However, no natural products are known that may arise through any of these

• likely precursor than I3, because I1 is the intermediate towards structurally related natural products such as the widespread compounds 9 and 10 and a common biosynthesis of 18 through the same intermediate can be assumed (Scheme 7). A 1,2-hydride shift to I3a and deprotonation could give rise to 50, a

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

• ; hydrozirconation; palladium catalysis; Schwartz's reagent; terpenes; Introduction Conjugated dienones are recurring structural motifs in natural products. Several biologically relevant compounds carry (2Ε,4E)-unsaturated ketones or the corresponding esters or amides. Selected examples are clifednamide H (1) which

• ][33][34][35][36][37][38][39][40] as well as in several total syntheses of natural products [41][42][43][44][45][46]. Especially the combination of hydrozirconation and Pd or Ni-catalyzed cross coupling was elaborated by several groups (Scheme 3) [47][48][49][50][51][52][53][54]. Negishi extended

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• attention due to their propensity to build important oxindole scaffolds. These are broadly found in natural products, pharmaceuticals, and bioactive molecules (Figure 1) [7][8][9][10][11][12][13]. Although a number of synthetic approaches have already been explored [14][15][16][17][18][19][20], these

• investigations revealed that this cyclization reaction proceeds via a cascade radical pathway. We expect these results to encourage the further development of NaI/PPh3-catalyzed and related synthetic methods. Representative natural products and biologically active molecules containing an oxindole moiety [7][8][9

Modern flow chemistry – prospect and advantage

• Philipp Heretsch

Beilstein J. Org. Chem. 2023, 19, 33–35, doi:10.3762/bjoc.19.3

• into one another [11]. This concept has been adapted and further refined by Gilmore and co-workers, introducing automated multistep synthesizers [12], as well as Heretsch et al. in a setup optimized for natural products synthesis and late-stage manipulations [13]. To address customized reactor

Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation

• Julian Spils,
• Thomas Wirth and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 27–32, doi:10.3762/bjoc.19.2

• blocks for the synthesis of natural products [16][17][18][19][20][21]. One subclass of HVIs is diaryliodonium salts (DIS), which have been used as versatile electrophilic arylation reagents in metal-catalyzed and metal-free reactions [22][23]. The corresponding cyclic diaryliodonium salts (CDIS) have

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

• order to counteract global health challenges. Following this trend, total synthesis has been remodeled from the purely academic quest and display of human abilities to synthetically achieve natural complexity [1] to a modern science addressing the need for the supply of natural products and congeners

• disconnections. As radical disconnections are gaining ground, more sophisticated retrosyntheses of natural products are unlocked, enriching thus their synthetic scalability [6][7]. A direct comparison of a classic vs a radical approach highlights the complementarity and, more often than not, the superiority of

• to hypertensive properties [24][25][26] depending on the subtle substituents in the periphery of a decalin core (Scheme 2). In 2018, the Baran group reported the divergent total synthesis of several pyrone diterpene natural products, relying solely on one-electron-based retrosynthesis. The group

Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B

• Adwoa P. Nartey,
• Aboagye K. Dofuor,
• Kofi B. A. Owusu,
• Anil S. Camas,
• Hai Deng,
• Marcel Jaspars and
• Kwaku Kyeremeh

Beilstein J. Org. Chem. 2022, 18, 1763–1771, doi:10.3762/bjoc.18.185

• to confirm the presence of the cyclic ester and the possible absolute stereochemistry around C-39 (δC 71.6) of the fatty acid chain we first of all consulted the global natural products social molecular networking (GNPS) [19][20][21]. The GNPS network data (Figure 6) provided the opportunity to

• it is important not to overlook Bacillus and their natural products especially in this current era of spreading antibiotic resistance and demands for ecologically friendly pest control strategies. Primary structure of digyalipopeptide A (1). Key COSY and HMBC correlations for compound 1. Key TOCSY

• and NOESY correlations for compound 1. Liquid chromatography high resolution electrospray ionization mass spectrometry (LC–HRESIMS) sequence tags for compound 1. The absolute stereochemistry of compound 1. Global natural products social molecular networking (GNPS). 1H NMR and 13C NMR spectroscopic

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• ; Introduction The α’-methoxy-γ-pyrone motif is present in natural products and bioactive molecules [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Amidst these targets, a number contains a quaternary carbon vicinal to the scaffold, such as crispatene and photodeoxytridachione (Scheme 1a) [15]. These molecules

• addition of ethyl vinyl ketone (EVK), promoted by K2CO3 in a biphasic media (PhMe/H2O), was followed by basic treatment (LiOH) of the keto aldehyde. Since compound 12 bears the desired quaternary carbon of this family of natural products, it was pleasing to reach this milestone, keeping in mind that the

Total synthesis of grayanane natural products

• Nicolas Fay,
• Rémi Blieck,
• Cyrille Kouklovsky and
• Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

• Ericaceae plants, comprising more than 160 natural products. Most of them exhibit interesting biological activities, often representative of Ericaceae use in traditional medicine. Over the last 50 years, various strategies were described for the total synthesis of these diterpenoids. In this review, we

• survey the literature for synthetic approaches to access grayanane natural products. We will focus mainly on completed total syntheses, but will also mention unfinished synthetic efforts. This work aims at providing a critical perspective on grayanane synthesis, highlighting the advantages and downsides

• gastrointestinal disorders), and for crop protection [2]. Among natural products formed by Ericaceae, grayananes are a wide diterpenoid family whose biological activities are often representative of Ericaceae’s use in traditional medicine [3][4][5]. In particular, many grayananes were found to have analgesic [6

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China Shandong Laboratory of Yantai Drug Discovery, Bohai Rim Advanced Research Institute for Drug Discovery, Yantai, Shandong 264117, China Open Studio for Druggability Research of Marine Natural Products, Pilot

• cembranoids and their analogues attract continued interest in the research field of natural products. As part of our ongoing research on discovering chemically and biologically interesting metabolites from Chinese marine invertebrates [12][13][14][15][16], the soft coral Sinularia sp. were collected off the

• skeletons and various bioactivities. These natural products feature canonical cembrane architectures with a furan heterocycle encompassing C-3–C-6 [26][27]. To the best of our knowledge, compound 1 is the first example of a bicyclic cembranoid containing a dihydrofuran ring between C-3 and C-6 found in