Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• is an important heterocyclic framework in natural products and biologically active molecules, and the efficient synthesis of this structural motif has received much attention in recent years. Herein, we report a (phenyliodonio)sulfamate (PISA)-mediated, solvent-dependent synthesis of different

• ); isoquinolinone; solvent-dependence; Introduction Isoquinolinone is an important heterocyclic structure found in many natural products and biologically active compounds, including pharmaceuticals [1]. For instance, lycoricidine, found in the medicinal plant Lycoris radiata, may inhibit the MCPyV LT protein

• . Selected natural products, pharmaceuticals, and biologically active compounds having an isoquinolinone scaffold. Chemoselective and PISA-mediated, solvent-controlled synthesis of different isoquinolinone derivatives 2 and 3. Substrate scope for the synthesis of 4-substituted isoquinolinones 2. Reaction

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• avoid opening of the furan ring. The authors explored the substrate scope by using different isocyanides and 2-aminoazines, obtaining 6 potentially bioactive pseudo natural products 35 in low to moderate yield (21–67%). Bräse et al. [45] reported the possibility of exploiting the GBB-3CR to synthesize a

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

• associated bioactive peptides. Keywords: antimicrobials; genome mining; lantibiotics; lanthipeptides; multi-drug resistant bacteria; natural products; Introduction Antimicrobial resistance (AMR) is a significant public health challenge. Only in 2019, there were 4.95 million deaths associated with AMR [1

• are derived from bacterial natural products (NPs), which have proven to be a valuable source of antimicrobial agents. During the latter part of the 20th century, the discovery of NPs was hindered by the limitation of traditional methods, which often led to the rediscovery of previously identified NPs

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 enzymatic transformations with chemical conversions. This review focuses on the total synthesis of natural products and classifies the enzymatic reactions into three categories. The total synthesis of five natural products: cotylenol, trichodimerol, chalcomoracin, tylactone, and saframycin A, as

• approach" merging efficient enzymatic synthesis – traditionally employed in the biosynthesis of natural products by microorganisms and plants – with precise chemical synthesis conducted by chemists. Chemo-enzymatic total syntheses reported recently fall into three main categories based on the purpose for

• stereoselective cyclization reactions. This review aims to provide an overview of these approaches and parallel comparisons with original biosynthetic pathways by highlighting five examples of chemo-enzymatic total syntheses of natural products reported since 2017. The examples are the synthesis of cotylenol (1

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

• within the context of ribosomally synthesised and post-translationally modified peptide (RiPP) natural products. Methyltransferases play a pivotal role in the biosynthesis of diverse natural products with unique chemical structures and bioactivities. They are highly chemo-, regio-, and stereoselective

• bioactivities [1]. RiPP natural products are typically encoded in a biosynthetic gene cluster (BGC) and produced following defined biosynthetic rules. Initially, a precursor peptide encompassing a core peptide, a leader part and/or a follower part, is synthesised at the ribosome. Next, distinct maturases

• resulting natural products with a spectrum of chemical complexity, contributing to the broad range of biological activities exhibited by RiPPs. Bioactivities attributed to RiPPs include a wide range of effects, such as antibiotic, antifungal, antiviral, antiparasitic, antitumour, analgesic, anti

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• novelty. In this review, we summarize the distribution of Microbulbifer bacteria, activities of the various polymer degrading enzymes that these bacteria produce, and an up-to-date summary of the natural products that have been isolated from Microbulbifer strains. We argue that these bacteria have been

• hiding in plain sight, and contemporary efforts into their genome and metabolome mining are going to lead to a proliferation of Microbulbifer-derived natural products in the future. We also describe, where possible, the ecological interactions of these bacteria in marine microbiomes. Keywords: bacteria

• ; hydrolases; marine natural products; Introduction Microbial natural products represent an important reservoir for drug discovery and along with their (semi)synthetic derivatives, constitute a major component of the contemporary pharmaceutical arsenal. Their thusly validated utility is juxtaposed against the

Mining raw plant transcriptomic data for new cyclopeptide alkaloids

• Draco Kriger,
• Michael A. Pasquale,
• Brigitte G. Ampolini and
• Jonathan R. Chekan

Beilstein J. Org. Chem. 2024, 20, 1548–1559, doi:10.3762/bjoc.20.138

• discovering diverse natural products from bacteria and fungi. In plants, this approach is often more limited due to the lack of available annotated genomes and transcriptomes combined with a less consistent clustering of biosynthetic genes. The recently identified burpitide class of ribosomally synthesized

• and post-translationally modified peptide (RiPP) natural products offer a valuable opportunity for bioinformatics-guided discovery in plants due to their short biosynthetic pathways and gene encoded substrates. Using a high-throughput approach to assemble and analyze 700 publicly available raw

• transcriptomic data sets, we uncover the potential distribution of split burpitide precursor peptides in Streptophyta. Metabolomic analysis of target plants confirms our bioinformatic predictions of new cyclopeptide alkaloids from both known and new sources. Keywords: burpitides; natural products; plants; RiPPs

Primary amine-catalyzed enantioselective 1,4-Michael addition reaction of pyrazolin-5-ones to α,β-unsaturated ketones

• Pooja Goyal,
• Akhil K. Dubey,
• Raghunath Chowdhury and
• Amey Wadawale

Beilstein J. Org. Chem. 2024, 20, 1518–1526, doi:10.3762/bjoc.20.136

• ; organocatalysis; pyrazoles; Introduction N-Heterocycles are attractive molecules owing to their extensive applications in small-molecule drugs, natural products, and agrochemical products [1][2][3]. Among the N-heterocycles, pyrazole is an important structural scaffold, found in several marketed drugs and

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• ][18]. Owing to the prevalence of aliphatic carboxylic acids in biomass and natural products, decarboxylative cyanation represents one of the most straightforward and attractive approaches to accessing alkylnitriles [19][20]. As an elegant example, Barton demonstrated the application of redox-active

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

• University, Hangzhou 310030, China Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310030, China 10.3762/bjoc.20.131 Abstract Polyketides are a major class of natural products, including bioactive

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• efficient strategies for accessing functionalized pyrazole derivatives. Thio/selenocyano groups are widely existing in the core structural motifs of various natural products and pharmaceutical agents [16][17][18][19][20]. Many S/SeCN-containing bioactive small molecules have been proved to possess wide

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• natural products, pharmaceuticals, and functional materials (Figure 1) [1][2][3]. It has been assessed that almost one-third of the best-selling therapeutics contains fused heterocyclic structures [4]. Among the N-heterocycles, imidazopyrazine structures [5][6], derived from amalgamation of privileged

• a new example of cyclic N,O-aminals and carbinolamine derivatives, an interesting class of organic compounds that are common structural motifs embedded within diverse biologically important natural products and pharmaceuticals [32][33][34][35][36][37]. On the other hand, the N,O-aminals are stable

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• intramolecular synthetic strategies. Immense applications in the synthesis of hydroxy acids and esters, heterocycles, fused carbocycles, natural products, and others with broad substrate scope have raised profound interest from methodological and synthetic standpoints. The ongoing development of reagents

• potentially useful molecules. Keywords: Cannizzaro reaction; crossed-Cannizzaro; desymmetrization; Lewis acid catalyst; natural products; Introduction The synthesis of functionalized molecules with structural complexity has always been a challenge to synthetic chemists. The Cannizzaro reaction, in its

• methodologies, such as Lewis acid catalysis, desymmetrization of symmetrical dialdehydes, synthesis of natural products, and building blocks. These modifications constitute the main highlight of this review. The use of modern technology and newer strategies aiming towards industrial benefit is the goal for the

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• natural products containing a foundational 6/10-bicyclic framework and can be divided into two main classes, cis and trans, based on the configurations of their ring fusion at C1 and C10. Previous studies on two bacterial diterpene synthases, Bnd4 and AlbS, revealed that these enzymes form cis- and trans

• rearrangement; DFT calculations; diterpene; electrophilic cyclization; eunicellane; Introduction The eunicellane diterpenoids are a family of nearly 400 natural products that present a conserved 6/10-bicyclic hydrocarbon framework [1][2][3]. Mostly known from soft corals [2], but with a growing number of

• functional groups at C6 (Figure 4). The goals were to evaluate the scope of electrophile-mediated cyclization and diversify the gersemiane skeleton for bioactivity assays. A structural similarity search of 5 and 6 revealed that several natural products, including the coral gersemiols [24] and plagicosin N

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

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• derived from germecrene A. Keywords: carbocation; germacrene A; hedycaryol; stability trend; terpenes; Introduction Terpenoids form a large and highly diverse group of natural products with a wide range of usage in the pharmaceutical, cosmetic, agricultural, food, and energy industry. Among their

• , whereas natural products from C are unknown and a few sesquiterpenes are known products of D. Similarly, in the case of hedycaryols, cation A-OH can undergo deprotonations to yield α-eudesmol [20], β-eudesmol [14], or γ-eudesmol [15]. Cation B-OH can potentially lead to alcohols by deprotonation or to

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• ; indanones; Nazarov reaction; Introduction Natural products are the source of inspiration for several research groups that develop new synthetic methodologies. The chemistry of five-membered rings plays an important role in organic chemistry, both because of the wide occurrence in nature [1][2][3][4][5][6

• found in a series of natural products and synthetic molecules with different biological activities [11][80][81]. In particular, 1-indanones substituted in position 3 are important synthons for some drugs and natural products [82][83][84]. A bibliographic survey revealed that some methods were developed

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• are of substantial importance for the fine chemical industry, pharmaceuticals, agrochemicals, dyes, and natural products [25]. The synthesis of amine derivatives can be accomplished using many powerful techniques, including Buchwald–Hartwig and Ullmann cross-coupling reactions, hydroamination

• interrupted BH approach using Mn26 (3 mol %) and t-BuOK (50 mol %) in toluene at 130 °C for 24 h (Scheme 67). Fascinatingly, this process was used to synthesize pharmacologically active compounds like vibrindole A and turbomycin B alkaloids and natural products like gramine and dipterine analogues. Discrete

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

• , Indiana 47906, United States 10.3762/bjoc.20.88 Abstract Natural products (NPs) are fantastic sources of inspiration for novel pharmaceuticals, oftentimes showing unique bioactivity against interesting targets. Specifically, NPs containing furan moieties show activity against a variety of diseases

• products, methylenomycin furan (MMF) hormones, and MMF derivatives. Moreover, the molecular probe has been tested in crude supernatants of various Streptomyces strains and enables identification of MMFs. Keywords: Diels–Alder reaction; furans; methylenomycin furan hormones; natural products; reactivity

• -based probes; Introduction To date, natural products and their derivatives have served as the foundation of many pharmaceuticals used today. These compounds have activity against various diseases such as cancer, bacterial infections, and fungal infections, as well as other indications [1]. Specifically

Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, Hubei 430071, China 10.3762/bjoc.20.86 Abstract Terpenoids are one of the largest class of natural products with diverse structures and activities. This enormous diversity is embedded in enzymes called terpene synthases (TSs), which

• multisubstrate terpene synthases (MSTSs) and highlight their potential applications. Keywords: noncanonical terpene; substrate promiscuity; synthetic biology; terpene synthase; terpenoid; Introduction Terpenoids constitute the largest class of natural products with more than 80000 known structures [1] and a

• noncanonical prenyl substrates Most of the terpene biosynthesis is well defined by the ‘isoprene rule’ to form natural products by the polymerization of C5 isoprene. Although terpenes with irregular carbon atoms (C6, C7, C11, C12, C16, and C17) have been characterized, they are thought to be synthesized by

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• -lactam ring is a privileged scaffold widely present in drugs and natural products [12][13][14], as shown in Scheme 1. Herein, we report the effective desymmetrization strategy of N-protected 2,5-dihydro-1H-pyrroles using aryldiazonium salts and the chiral N,N-ligand (S)-PyraBox (Scheme 2). The obtained

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• can be found in natural products and synthetic compounds with antitumor, anti-HIV, antibiotic, antifungal, antivirus, and anti-inflammatory activities [18][19][20][21]. The antischistosomal drug praziquantel (PZQ), a tetrahydroisoquinoline derivative, is a commercialized drug for the treatment of

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• natural products and pharmaceutical agents, including antifungal drugs [1][2][3], and hence their selective preparation has attracted considerable attention from the synthetic community. Compared to methods for the de novo construction of azole heterocycles, direct functionalization of the azole N–H bond

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• cyclization mechanism of spiroviolene. Keywords: boron migration; diterpene; spiroviolene; stereochemistry; Introduction Terpenes represent one of the most fascinating families of natural products due to their structural complexity and diversity, as well as their indispensable biological functions that

• ancestors of SvS generated by ancestral sequence reconstruction [8][9]. Related natural products with the same 5-5-5-5 tetracyclic ring system, including spirograterpene A (2) from Penicillium granulatum MCCC 3A00475 [10], and GJ1012A (3) from an engineered E. coli strain harboring FgGS (FgJ07623) cloned

• IM-7. A key 1,3-hydride shift of IM-7 from the β-face, followed by deprotonation of the formed C2-cation IM-8, would deliver the originally proposed structure 1' [6]. However, no related natural products that would be derived from the intermediates of this pathway have been found so far. A third

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

• protect bacteria from exposure to NNG. Keywords: enzymology; natural products; nitramine; N–N bond; Introduction Degradation of nitramines (R–N(R′)NO2; R′ = H or alkyl) has been well studied in the context of the environmental degradation of explosive cyclic nitramines [1][2]. The cyclic nitramines

• , the physiological function of its substrate NNG. This compound is one of the few known nitramine natural products and the only one produced by bacteria instead of fungi [22]. Its only known natural sources are strains of Streptomyces bacteria [23][24]. The abundance and distribution of these NNG

• and kinetic experiments or crystallization of the active homodimer will be required to resolve the catalytic mechanism. If NnlA is specific for NNG as suggested by these results, it is worth speculating about potential functions of NNG and other nitramine natural products. Bacterial natural products