Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• environmentally friendly than other frequently used hydrogen sources like hydrosilanes [17], tributyltin hydride (Bu3SnH) (often used in natural product syntheses) [18][19][20] and hydroboranes [21][22][23], since the only byproduct is water. The production, storage and use of H2 received much attention and

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• Panagiotis S. Gritzapis Panayiotis C. Varras Nikolaos-Panagiotis Andreou Katerina R. Katsani Konstantinos Dafnopoulos George Psomas Zisis V. Peitsinis Alexandros E. Koumbis Konstantina C. Fylaktakidou Laboratory of Organic, Bioorganic and Natural Product Chemistry, Molecular Biology and Genetics

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• for modern synthetic chemistry, and we believe that the application in natural product synthesis and meta functionalization is highly desirable. In addition to this, to provide high selectivities and to allow for the combination of dual photoredox catalysis with HAT, the discovery of more effective

Copper-catalyzed enantioselective conjugate addition of organometallic reagents to challenging Michael acceptors

• Delphine Pichon,
• Jennifer Morvan,
• Christophe Crévisy and
• Marc Mauduit

Beilstein J. Org. Chem. 2020, 16, 212–232, doi:10.3762/bjoc.16.24

• the morpholine group could easily allow further postfunctionalizations. Furthermore, thanks to the highly 1,6-enantioselective additions of methylmagnesium bromide (95% ee), this methodology was applied to the synthesis of the natural product penicillenol A by oxidative cleavage of the resulting 1,6

Rapid, two-pot procedure for the synthesis of dihydropyridinones; total synthesis of aza-goniothalamin

• Thomas J. Cogswell,
• Craig S. Donald and
• Rodolfo Marquez

Beilstein J. Org. Chem. 2020, 16, 135–139, doi:10.3762/bjoc.16.15

• right [7][8][9][10][11][12][13]. The relevance of dihydropyridones as lead compounds is exemplified by the detailed investigations into the synthesis and biological evaluation of aza-goniothalamin 1 and its analogues (Figure 1). (R)-(+)-Goniothalamin 2, a natural product isolated in 1967, was shown to

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• , Indonesia Marine Science Techno Park, Diponegoro University, Teluk Awur Campus, St. Undip, Jepara District, Central Java, Indonesia Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan 10.3762/bjoc.15.289 Abstract In our natural product screening

Chemical synthesis of tripeptide thioesters for the biotechnological incorporation into the myxobacterial secondary metabolite argyrin via mutasynthesis

• David C. B. Siebert,
• Roman Sommer,
• Domen Pogorevc,
• Michael Hoffmann,
• Silke C. Wenzel,
• Rolf Müller and
• Alexander Titz

Beilstein J. Org. Chem. 2019, 15, 2922–2929, doi:10.3762/bjoc.15.286

• has been observed in many cases that exogenous substrates can be incorporated by bacteria into biosynthesis cascades of natural products. The use of substrates which lead to nonnatural derivatives of the natural product coined the field of mutasynthesis, e.g., siderophore analogue biosynthesis by P

• synthesis of this complex natural product (Supporting Information File 1, Figure S1). Results and Discussion In order to establish the mutasynthesis of argyrins, we designed the native sequence mutasynthon 14 and various synthetic analogs of this initiating tripeptide for argyrin mutasynthesis with

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• bioactivities [24][25]. Modifying the cannabinoid profile through engineering would therefore be of significant interest. The biosynthetic promiscuity, the hallmark of terpene biosynthesis, sets terpenes apart from other natural product classes and is a product of their distinctive biosynthetic logic

• . Biosynthetic core enzymes of well-characterized classes of natural products, such as modular thiotemplate assembly lines (NRPSs, PKSs), are usually highly specific and produce only a few closely related natural product analogs. Adenylation domains in NRPSs [26][27][28], acyltransferase (AT) domains in cis-AT

• PKSs [29], and ketosynthase domains in trans-AT PKSs [30][31] are highly substrate-specific and function as gatekeepers to ensure that a single natural product is produced with high efficiency. Erroneous or stalled intermediates are removed from the assembly lines [32][33]. Novelty in these assembly

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• correlations between the protons H2-1/2/17/18 and C-3′ (δ = 144.9 ppm). Additionally, long-range correlations between the protons H2-1 and H3-6′ were observed in the COSY spectrum. Therefore, the structure of natural product 1 was unambigously concluded to be 1,18-bis[4′-methyl-2′,5′-dioxo-3′-furyl]octadecane

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• number of perfumes with varying percentages and is the first example being used as a pure fragrance. Structurally, it is related to natural terpenes like many other synthetic fragrances. And indeed, the story began with a classic in the field of fragrances, the natural product ionone. Keywords

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• alkyne metatheses. A selection of such complexes is shown in Figure 1. Molybdenum alkylidyne complex I with siloxide ligands (X = OSiPh3) [10][11] is widely used in natural product synthesis, predominantly through ring-closing alkyne metathesis (RCAM) [12][13][14][15][16][17][18][19][20]. The metathesis

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• Natural Product Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba Peoples´ Friendship University of Russia (RUDN University) Miklukho-Maklaya Street 6, 117198 Moscow, Russia 10.3762/bjoc.15.237 Abstract An efficient sequence based on the Ugi-azide reaction and

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• carbon skeletons of other bioactive natural product classes. In light of this fact, the exchange of only one amino acid changes the product portfolio from cyclooctatin (5) belonging to the fusicoccane diterpene family to compounds of the dolabellane [67] or the cembranoid class [68]. The dolabellane

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• analysis revealed that 1 is an unsaturated fatty acid in which a methyl group is located in an uncommon position as a natural product. Feeding experiments of 13C-labeled precursors clarified that ʟ-methionine-derived methylation takes place at the carbon which is derived from the carbonyl carbon of acetate

• -derived bacteria, (2Z,4E)-3-methyl-2,4-decadienoic acid (1) was obtained from the culture extract of Microbulbifer sp. C4-6 isolated from a stony coral Porites sp. (Figure 1). Compound 1 is known as a synthetic compound [12] but this is its first discovery as a natural product. In addition, 1 is

• fatty acid/polyketide biosynthesis. Compound 1 and its (2E,4E)-isomer were reported previously as synthetic compounds but this is the first finding of 1 as a natural product [12][21]. Very recently, benzoate derivatives were reported from a marine-derived Microbulbifer [22]. Therefore, this is the

Synthesis of acremines A, B and F and studies on the bisacremines

• Nils Winter and
• Dirk Trauner

Beilstein J. Org. Chem. 2019, 15, 2271–2276, doi:10.3762/bjoc.15.219

• acremines A and B. The dimerization of acremine F to bisacremine E was investigated but could not be achieved, shedding light on the formation of the acremine dimers in nature. Keywords: meroterpenoid; natural product; selective oxidation; total synthesis; Introduction Endophytic fungi grow in a symbiotic

• should then close the tetrahydrofuran ring of the natural product. Upon irradiation of 5 using a Hg lamp, however, the only productive pathway which could be observed was isomerization of the disubstituted double bond (Table 1, entries 17 and 18). Again, we attempted to promote the reaction by tethering

• modestly enantioselective oxidation and a highly enantioselective reduction with kinetic resolution to access the acremine framework. The route proved to be scalable and delivered 300 mg of the natural product. Acremine F could further be converted into acremines A (1) and B (2) by a selective oxidation

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• be cultivated for further purposes like taxonomic identification or natural product isolation. Isolation methods like baiting may lead to bait-specific fungi only. A strain of A. umbrinum was isolated by Deshmukh et al. using a hair baiting technique. The majority of those isolates showed

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• length of the extended pentafulvene chain, and the role of the fulvene in the reaction (diene or dienophile) [127]. In these examples, kigelinol and neoamphilectane are of great interest in biomimetic and natural product chemistry, as they exhibit antitrypanosomal [128][129] and antimalarial [130

• synthetically interesting scaffolds have been synthesised, including products which exhibit biological activity, complex ligands in coordination chemistry, and several natural product skeletons (Table 3). Applications of fulvene cycloadditions Organic and natural product synthesis A variety of organic molecules

• al. developed a programmable enantioselective one-pot synthesis of molecules with eight stereocentres greatly improving the efficiency of natural product synthesis [83]. Each of these natural products are biologically active, hence their total synthesis will allow further characterisation of their

A review of the total syntheses of triptolide

• Xiang Zhang,
• Zaozao Xiao and
• Hongtao Xu

Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194

• Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China 10.3762/bjoc.15.194 Abstract Triptolide is a complex triepoxide diterpene natural product that has attracted considerable interest in the organic chemistry and medicinal chemistry societies due to its intriguing structural features

Molecular basis for the plasticity of aromatic prenyltransferases in hapalindole biosynthesis

• Takayoshi Awakawa and
• Ikuro Abe

Beilstein J. Org. Chem. 2019, 15, 1545–1551, doi:10.3762/bjoc.15.157

• Hapalindole/ambiguine alkaloids, isolated from cyanobacteria, are composed of the total C15 prenyl moieties derived from dimethylallyl diphosphate (DMAPP) and geranyl diphosphate (GPP), and cis-indolylvinyl isonitrile 1 (Figure 2A) [15]. This natural product family includes structurally diverse compounds with

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

• Leticia Monjas,
• Peter Fodran,
• Johanna Kollback,
• Carlo Cassani,
• Thomas Olsson,
• Maja Genheden,
• D. G. Joakim Larsson and
• Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

• , Gothenburg, Sweden 10.3762/bjoc.15.147 Abstract The synthesis and antibacterial activity of two new highly truncated derivatives of the natural product abyssomicin C are reported. This work outlines the limits of structural truncation of the natural product and consequently provides insights for further

Genomics-inspired discovery of massiliachelin, an agrochelin epimer from Massilia sp. NR 4-1

• Jan Diettrich,
• Hirokazu Kage and
• Markus Nett

Beilstein J. Org. Chem. 2019, 15, 1298–1303, doi:10.3762/bjoc.15.128

• the chemistry of the genus Massilia, in general. Because natural product-competent microorganisms typically synthesize multiple compounds [7], strain NR 4-1 appeared as a promising candidate to find further secondary metabolites. Further incentive for the chemical analysis of this bacterium came from

• biosynthetic precedence, MicH is responsible for the assembly of a thiazoline ring through condensation of a cysteine residue and subsequent cyclization [16]. The lack of MicH would hence indicate the absence of the corresponding thiazoline motif in the corresponding natural product. Based upon the assumption

• discrepancies in the observed chemical shifts, which suggested that the isolated natural product from Massilia sp. is not identical to agrochelin. Instead 1 and 2 are assumed to represent diastereomers. The occurrence of diastereomers is known for natural products, such as pyochelin and yersiniabactin, which

Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated O-, C-, N- and S-linked glycosides

• Madhu Babu Tatina,
• Xia Mengxin,
• Rao Peilin and
• Zaher M. A. Judeh

Beilstein J. Org. Chem. 2019, 15, 1275–1280, doi:10.3762/bjoc.15.125

• blocks especially for natural product synthesis [36][37][38][39][40]. Therefore, we used the perfluorophenyl boronic acid catalyst in the reaction between 2,3,4,6-tetra-O-acetyl-D-glucal (1a) and benzyl alcohol, n-butyl alcohol, cyclohexyl alcohol and p-toluenethiol (Figure 2). Gratifyingly, the reaction

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• Leslie Reguera Cecilia I. Attorresi Javier A. Ramirez Daniel G. Rivera Center for Natural Product Research, Faculty of Chemistry, University of Havana, Zapata y G, Havana 10400, Cuba Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

• Herman O. Sintim,
• Hamad H. Al Mamari,
• Hasanain A. A. Almohseni,
• Younes Fegheh-Hassanpour and
• David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

• (2). Natural product examples containing the monoalkylated tartaric acid motif. Carbonyl ylide cycloaddition–rearrangement to the squalestatin core [12][13]. Tartrate alkylation strategy to cycloaddition substrate. Conversion of α-ketoester to α-diazoester. Seebach’s tartrate alkylation and

Heck- and Suzuki-coupling approaches to novel hydroquinone inhibitors of calcium ATPase

• Robert J. Kempton,
• Taylor A. Kidd-Kautz,
• Soizic Laurenceau and
• Stefan Paula

Beilstein J. Org. Chem. 2019, 15, 971–975, doi:10.3762/bjoc.15.94

• tether to BHQ that terminated in a leucine moiety to obtain target 14. Similar to related compounds based on the structure of the natural product thapsigargin, 14 displayed inhibitory potency against SERCA activity. This makes 14 a suitable candidate for the future attachment of a deactivating peptide to

• [1][2]. The natural product thapsigargin (TG, 1a, Figure 1) is one of the most frequently used SERCA inhibitors because of its high specificity and potency. Both cancerous and healthy cells undergo apoptosis after exposure to low concentrations of TG, making TG a highly potent but nonselective