Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• strain from the Red Sea (Egypt), further enriching the borrelidin series. A halophilic actinomycete strain (HYJ128) from Jeung-do Island (Shinan-gun, Jeollanamdo, Korea), belonging to the genus Nocardiopsis, inhabits a hypersaline saltern and was found to produce a series of new polyketide-derived

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• activity of this polyketide. Seven analogues of massarilactone D, compounds 2–8, were synthetized through acylation modifications aimed at enhancing the compound’s interactions with biological targets (Scheme 1). These acylated analogues were subsequently screened for their cytotoxicity against a panel of

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• previously reported study investigating the biosynthesis of tenellin from Beauveria bassiana CBS110.25 [13], it was established that tenellin and a vast array of related metabolites could be synthesized through a cascade involving hybrid highly reducing polyketide synthase–non-ribosomal peptide synthetase

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• purities (Scheme 3). Sparr and co-workers developed an atroposelective synthesis for tetra-ortho-substituted biaryls 11 by non-canonical polyketide cyclizations [21]. This work was based on an earlier report of the team on the aldol cyclization of naphthyl-substituted unsaturated ketoaldehydes [22]. The

• process was inspired by the biocatalytic synthesis of aromatic polyketides by polyketide synthase from poly β-carbonyl substrates. Pyrrolidine-based organocatalyst C4 was able to promote a twofold atroposelective arene-forming 6-enolendo aldol condensation (Scheme 4). Sparr also realized a central-to

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

• ]. Type I PKs are also constructed in a modular assembly line biosynthetic logic and may be amenable to chemical structure metagenomic approaches described herein [82]. In fact, the software suite antiSMASH can already predict the substrate specificity of individual polyketide synthase (PKS) modules, i.e

• ]. Last but not least, predicted polyketide structures can be synthesized in a streamlined and automated fashion by using a microfluidic device reported by Burke and co-workers [84][85]. As such, the necessary computational and synthetic tools are all in place to examine the PK chemical space and to

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• acid), whose biosynthesis is presumably starting from alternariol. The lactone moieties of these compounds are usually six-membered rings, where variations during or after polyketide synthesis occasionally give rise to five- or seven-membered rings or even to open structures with a free resorcylic acid

• polyketide synthase (PKS) into account [25], since polyketides like zearalenone are synthesized by means of a type I PKS [22][26], while alternariol and its derivatives are likely to be obtained by catalysis with a PKS of type II [27] or possibly of type III [28]. However, no reliable information in this

• biological activity was determined for these compounds. Pestauvicomorpholine A (34) is an exceptional hybrid metabolite with fusion of a polyketide-derived resorcylic lactone and the steroid dihydroergosterol, which was isolated from the fungus Pestalotiopsis uvicola [174]. Its structure was determined by

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

• Moisés Alejandro Alejo Hernandez,
• Katia Pamela Villavicencio Sánchez,
• Rosendo Sánchez Morales,
• Karla Georgina Hernández-Magro Gil,
• David Silverio Moreno-Gutiérrez,
• Eddie Guillermo Sanchez-Rueda,
• Yanet Teresa-Cruz,
• Brian Choi,
• Armando Hernández Garcia,
• Alba Romero-Rodríguez,
• Oscar Juárez,
• Siseth Martínez-Caballero,
• Mario Figueroa and
• Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

• cellulolyticum, and clostrubin, a polyphenolic polyketide antibiotic and the first reported polyketide from anaerobic bacteria [35][36][37]. Therefore, the discovery of a lantibiotic with a Clostridium origin, reported in this study, has significant implications for developing novel antibiotics. The unique

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• biosynthetic pathway as proposed by Cox, based on bioinformatic analyses of polyketide synthase (PKS) modules and in vitro studies. Initially, highly reducing iterative polyketide synthase (HR-iPKS) SorbA forms the thioester 30 on its acyl carrier protein (ACP) domain from acetate and two units of malonyl-CoA

• . Subsequently, the downstream HR-iPKS module, SorbB, catalyzes both the extension of polyketide chain from 30 using two additional malonyl-CoAs and C-methylations exploiting two units of SAM (S-adenosyl methionine) to generate thioester 31 on the ACP domain. Then, the reduction (Red) domain located at the C

• ]. In the field of chemo-enzymatic total synthesis utilizing polyketide synthase (PKS)-related macrocyclization enzymes, Xiang and co-workers recently reported the total synthesis of cylindrocyclophanes [64]. The cyanobacterial non-canonical enzyme CylK, discovered and characterized by Balskus and co

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• regeneration systems have been widely applied to small molecules [28][29][30], as well as polyketide natural products [31], and RNA [32]. To the best of our knowledge, these systems have not yet been applied to peptide natural products. By providing a comprehensive overview of the various methylation options

• acceptor molecules such as the polyketide rapamycin [31] or DNA [143]. The use of RiPP MTs with SAM supply or SAM regeneration systems has the potential to greatly increase chemical diversity of RiPP natural products. The addition of alternative alkyl groups onto peptide substrates could further expand the

Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain

• Changjun Xiang,
• Shunyu Yao,
• Ruoyu Wang and
• Lihan Zhang

Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131

• medicines such as erythromycin and rapamycin. They are often rich in stereocenters biosynthesized by the ketoreductase (KR) domain within the polyketide synthase (PKS) assembly line. Previous studies have identified conserved motifs in KR sequences that enable the bioinformatic prediction of product

• : bioinformatics; conserved motifs; ketoreductase; polyketide synthase; stereocontrol; Introduction Type I modular polyketide synthases (PKSs) are large enzyme complexes that play a crucial role in the biosynthesis of bacterial polyketides, including many important clinical drugs such as erythromycin (antibiotic

• -positions of a polyketide chain [5][6][7]. KRs are classified into three types: A-type and B-type denote KRs that form ʟ- and ᴅ-configured β-hydroxy products, respectively, while C-type denotes KRs incapable of reducing the β-keto group [8][9]. KRs are further classified into subtypes 1 and 2 when the

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• cofactor-independent manner. Keywords: angucyclines; aromatic polyketide; biosynthesis; cofactor-independent oxygenase; oxidative rearrangement reaction; Introduction The angucyclines represent a large class of natural products biosynthesized by type II polyketide synthases. Within this category, a

A Diels–Alder probe for discovery of natural products containing furan moieties

• Alyssa S. Eggly,
• Namuunzul Otgontseren,
• Carson B. Roberts,
• Amir Y. Alwali,
• Haylie E. Hennigan and
• Elizabeth I. Parkinson

Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88

• , natural products containing furan moieties (Figure 1A) are of interest as they have shown promising biological activities. One well-studied example is the antifungal flufuran, which was isolated from Aspergillus flavus [2]. Another example is plakorsin D, an anticancer polyketide natural product which was

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• . NNG is a non-proteinogenic amino acid, similar to other such N–N containing compounds such as piperazic acid and hydrazinoacetic acid [43]. These precursors are incorporated into larger NPs by non-ribosomal peptide synthases or polyketide synthases, and NNG may have a similar fate [44][45]. Another

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• -acyltransferase polyketide synthase biosynthetic gene cluster sdl (80 kb) from Streptomyces sp. B59 was cloned and transferred into a heterologous host, Streptomyces albus J1074, resulting in the production of a class of polycyclic macrolide shuangdaolides A (1), B, and D and dumulmycin (2) [29]. Furthermore

• , genome mining of the marine actinomycete Streptomyces seoulensis A01 enabled the identification of a giant type I polyketide synthase gene cluster (asm) [30]. Heterologous expression of the cryptic asm cluster using a bacterial artificial chromosome vector in a heterologous host led to the production of

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• second ketosynthase of the polyketide synthase BaeJ involved in bacillaene biosynthesis (BaeJ-KS2). For this purpose, both enantiomers of a 13C-labelled N-acetylcysteamine thioester (SNAC ester) surrogate of the proposed natural intermediate of BaeJ-KS2 were synthesised, including an enzymatic step with

• glutamate decarboxylase, and incubated with BaeJ-KS2. Substrate binding was demonstrated through 13C NMR analysis of the products against the background of various control experiments. Keywords: bacillaene; biosynthesis; enzyme mechanisms; isotopes; trans-AT polyketide synthases; Introduction Polyketides

• are a large class of natural products which often exhibit potent biological activities for their application in medicine, e.g., as antibiotics or immunosuppressants [1]. Despite their high structural variability all compounds from this class are commonly made through the action of polyketide synthases

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• and multifunctional enzymatic assembly, nonribosomal peptide synthases (NRPS), polyketide synthases (PKS), and hybrid NRPS/PKS systems, which are organized into sets of functional domains known as modules and function through a similar mechanism [9][10][11][12]. Each NRPS module is composed of three

• terminal polyketide synthases (PKSs) in juvenimicin biosynthesis in 2017 [75], which presented a chance to accomplish the chemoenzymatic total syntheses of tylactone and the juvenimicins (Scheme 7). To generate an appropriately activated tylactone hexaketide intermediate 49, two key fragments, aldehyde 42

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• draft genome sequence of the H002 strain identified the variochelin biosynthetic gene cluster (var), which encodes PKS (polyketide synthase) and NRPS (non-ribosomal peptide synthetase) genes. Finally, the siderophores isolated in this study exhibited antibacterial activity against several bacteria

• in Supporting Information File 1). To investigate whether the identified var biosynthetic gene cluster is responsible for variochelin production, we substituted varG encoding the polyketide synthase (PKS) module with a chloramphenicol resistance (cmR) gene cassette, using homologous recombination

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• a general understanding of their biosynthesis [7][8]. Polyketide–terpenoid hybrids are among the largest families of meroterpenoids. Orsellinic acid, an aromatic polyketide, and its analogues have been commonly identified as polyketide components in fungal meroterpenoids. Notably, 3,5

• polyketide moiety, contributing to structural diversification [9][10]. By contrast, in the biosynthesis of meroterpenoids derived from orsellinic acid and 5-methylorsellinic acid (5-MOA), the prenylation reaction typically occurs at the non-substituted carbon atom and thus preserves the aromaticity of the

• polyketide portion [11][12][13][14]. One exception has been found in funiculolide biosynthesis, in which a 5-MOA-derived phthalide undergoes dearomatizing prenylation catalyzed by the UbiA-like prenyltransferase FncB (Figure 1B) [15]. In addition to prenyltransferases, transmembrane terpene cyclases play a

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• structures, and are partially derived from terpenoids [1]. Many fungal meroterpenoids are composed of polyketide and terpenoid moieties. Examples of fungal meroterpenoids include mycophenolic acid (Figure 1, 1), which shows immunosuppressive activity and cell differentiation-inducing activity by inhibiting

• Aspergillus oryzae, will be also introduced. Review Standard reactions of fungal meroterpenoid biosynthesis The skeletal diversity within this group of compounds arises from polyketide synthesis, prenyl transfer, terpenoid cyclizations, and post-cyclization modifications [5]. In these reactions, terpenoid

• metabolic genes for ease of gene transfer and high substance production capabilities [10][11]. The expression of trt4 (polyketide synthase, PKS), trt2 (prenyltransferase, PT), trt5 (methyltransferase, MT), trt8 (flavin-dependent monooxygenase, FMO), and trt1 (meroterpenoid cyclase, CYC) in A. oryzae NSAR1

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• reaction enabled us to perform a kinetic analysis of AvaA7, which confirmed that AvaA7 catalyzes the denitrification of 3-diazoavenalumic acid in avenalumic acid biosynthesis. This study deepened our understanding of the highly reducing type II polyketide synthase system as well as the diazotization

• biosynthetic pathway [13]. In this pathway, 3-amino-4-hydroxybenzoic acid (3,4-AHBA, 1), synthesized by AvaH and AvaI, is loaded onto AvaA3 (carrier protein) by AvaA1 (AMP-dependent ligase), resulting in 3,4-AHBA-AvaA3. A highly reducing type II polyketide synthase (PKS) system [15][16] (AvaA2, A4, A5, and A8

• by co-expressing with the sfp gene to obtain the holo-form of CmaA3 [21]. We tested whether CmaA1 and holo-CmaA3 are involved in the initial reaction in polyketide synthesis similar to AvaA1 and AvaA3; AvaA1 loads 3,4-AHBA (1) onto holo-AvaA3 using ATP in the biosynthetic pathway of avenalumic acid

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• polyketide 1, and an acetylated alternariol 2 were isolated, along with fifteen known secondary metabolites. Their structures were established by extensive NMR spectroscopy and mass spectrometry analyses, as well as by comparison with literature data of their analogs. Keywords: alternariol; Diaporthe

• ; endophytic fungi; hemiketal polyketide; Introduction Endophytic fungi are organisms that reside almost ubiquitously inside the fresh healthy tissue of plants, and they may increase the resistance of the host tropical trees to survive in extreme conditions [1]. As the global diversity of endophytic fungi is

• great structural variability such as polyketides, terpenoids, polyketide synthase–nonribosomal peptide synthetase (PKS–NRPS) alkaloids, and cytochalasins, which have been considered as taxonomic markers of the genus [7][8][9][10]. However, it is worthwhile to mention that the name Phomopsis should no

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

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

• erythromycin A [18], Woodward famously introduced thianes and ring-fused thianes (dithiodecalins) as building blocks for polyketide chain fragments, in order to be able to exploit their cyclohexane-like conformational behavior in the control of the relative stereochemistry along the polyketide backbone (Scheme

Navigating and expanding the roadmap of natural product genome mining tools

• Friederike Biermann,
• Sebastian L. Wenski and
• Eric J. N. Helfrich

Beilstein J. Org. Chem. 2022, 18, 1656–1671, doi:10.3762/bjoc.18.178

• -like pathways are canonical type I cis-acyltransferase polyketide synthases (PKSs) and type A non-ribosomal peptide synthetases (NRPSs) (Figure 2A) [25][26]. The substrate specificity of the specificity conferring domains in each module can be predicted from the sequences of adenylation (A) (for NRPS

• harbor non-canonical module architectures and cryptic domains [19][22]. As a result, the colinearity rule cannot be applied to predict trans-AT PKS-derived polyketide core structures [19]. Instead, it has been observed that the amino acid sequences of the ketosynthase domains in trans-AT PKSs correlate

• with their substrate specificity [27]. This correlation can be used for the prediction of trans-AT PKS-derived polyketide core structures and is referred to as the correlation rule [19]. All commonly occurring domains in assembly line-like NP biosynthetic pathways as well as their non-modular homologs

Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

• Houchao Xu,
• Anne Wochele,
• Minghe Luo,
• Gregor Schnakenburg,
• Yuhui Sun,
• Heike Brötz-Oesterhelt and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

• , People's Republic of China Institute of Inorganic Chemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany 10.3762/bjoc.18.120 Abstract An improved synthesis for tryptophan-dehydrobutyrine diketopiperazine (TDD), a co-metabolite of the hybrid polyketide/non-ribosomal peptide

• -AT, [3][4]) polyketide synthase (PKS) and non-ribosomal peptide synthase (NRPS) [2] with a dehydrating bimodule [5][6] involved in the installation of the remaining Z-configured double bond within the polyketide backbone [7]. Furthermore, a cytochrome P450 monooxygenase was recently shown to be