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

• was determined by total synthesis. The biological activities of these maniwamycins were also evaluated, and they showed antiviral activity against influenza (H1N1) virus and the causative agent of COVID-19, SARS-CoV-2. This was the first report of such activity for a natural product having an azoxy

Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins

• Zhongwei Hua,
• Nan Liu and
• Xiaohui Yan

Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68

• cell suspension culture, heterologous biosynthesis, and total synthesis [16][17]. Crocins can be obtained from plant cell culture, but the production is prone to epigenetic silencing and toxic intermediates. The chemical synthesis of crocins is challenging due to the presence of numerous chiral centers

• clearance in vivo. Only a few plants can produce crocins, and the content of crocins in these plants is very low. Due to the numerous chiral centers, the total synthesis of crocins is challenging. Therefore, heterologous biosynthesis of crocins utilizing the synthetic biology strategy holds great potential

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 their hybrids, thioesterase (TE) domains play a significant role in late-stage macrocyclization. These domains can accept mimics of native substrates in vitro and exhibit potential for use in total synthesis. This review summarizes the recent advances of TE domains in the chemoenzymatic synthesis

• method to produce analog libraries is critical for structure–activity relationship studies to enhance its specificity. Since the first total synthesis by Ohno and Izumiya in 1966 [31], tyrocidine A and its analogs have been synthesized by several groups employing viable strategies over the past half

• sequential NRPS genes. However, none of them contain the thioesterase domain, which is essential for late-stage cyclization [59]. In 2018, Wakimoto, Kuranaga and co-workers reported the first total synthesis of surugamide B (16) in 34% overall yield through the general SPPS process and the macrocyclization

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• ]. Two decades later, in 2012 the Overman group demonstrated the utility of this transformation in the total synthesis of (–)-aplyviolene, involving the diastereoselective coupling of a tertiary radical and an enone acceptor [38]. Further developments of this chemistry resulted in the general use of NHPI

• -derived NHPI esters has found application in the total synthesis of natural products, including the plant metabolite denobilone A and the highly oxidized dibenzocyclooctadiene lignans heteroclitin J and kadsulignan E [55]. Activation via charge-transfer complex formation Under conditions where oxidative

• of chemoselectivity can benefit from the multitude of mechanisms for their activation. Particularly, the use of RAEs in natural product total synthesis enables the assembly of strategic C–C bonds through radical coupling reactions that can draw from a wide range of reaction conditions (Scheme 37

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• analogues through the incorporation of alternative building blocks at different stages of synthesis. Keywords: chemical glycosylation; lipid II; peptidoglycan; polyprenyls; total synthesis; Introduction Lipid II (Figure 1) is an essential bacterial glycolipid involved in peptidoglycan biosynthesis [1]. It

• provides a practical avenue for producing substantial amounts of lipid II analogues. Consequently, this approach offers a more feasible means of addressing the demands associated with biophysical screening pursuits. Prior research in the field of total synthesis of lipid II has elucidated that specific

Correction: Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2024, 20, 170–172, doi:10.3762/bjoc.20.16

• ; total synthesis; We noticed a number of minor errors in our original publication, including in Supporting Information File 1, that mostly concern the percent yield given for some of the precursors. In addition, there was a larger error related to the yield for the key step of the total synthesis of the

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• -aryltetraline product 6 holds a skeleton similar to that of cyclolignan natural products (Figure 2), which have often been targeted by total synthesis [18]. Some of them like podophyllotoxin [25] and the semisynthetic derivative etoposide [26] have demonstrated valuable anticancer properties [19][20]. Thus, to

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• cascade [45], and base-promoted annulations with isatoic anhydrides [46]. Many other contributions in this field up to 2019 have been extensively reviewed [47][48][49], with special attention to the total synthesis and functional analysis of 2-alkyl-4-quinolones as microbial signaling molecules [50][51

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• tool for achieving molecular complexity. Their synthetic potential has been demonstrated by their application in the total synthesis of complex natural compounds [2][4][9][10][11][12]. A remarkable example of an amino-catalyzed cascade process was reported by Enders [11], a three-component cascade

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• expansion was carried out by employing 2-naphthol and 4-hydroxyindole (Scheme 34) [64]. Application in total synthesis In 2018, a guanidine bisthiourea-catalyzed highly enantioselective aza-Friedel–Crafts reaction was applied as a central step in the total synthesis of (+)-gracilamine. The reaction was

• . Total synthesis of (+)-gracilamine. Total synthesis of (−)-fumimycin.

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• pharmaceutically active molecules, polymer synthesis, total synthesis of natural products, porphyrin functionalization, and the synthesis of various pyrrole-containing heterocyclic molecules. We believe that this review will be useful and will encourage researchers to apply the modified Clauson–Kaas reaction to

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• ground state catalyst [21][22][23][24][25][26]. While early research has focused on methods for the functionalization of relatively simple hydrocarbons [27][28][29][30], developments in photoredox catalysis have gained traction recently as a viable strategy for the total synthesis of natural products [31

• demonstrated by the formal total synthesis of (±)-6,7-secoagroclavine (Scheme 4) [108][109][110][111][112][113][114]. Towards this end, compound 11 was methylated efficiently and selectively at the secondary amide by treatment with methyl iodide in DMF to afford compound 13. In additional two steps

• -catalyzed radical decarboxylative cyclization. Synthesis of compound 5. Photoredox-catalyzed radical decarboxylative cyclization of 5. Synthesis of tryptophan derivatives 8 and 10. Methylation of 11 and the formal total synthesis of (±)-6,7-secoagroclavine. Photoredox-catalyzed radical decarboxylative

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• thiazole or thiazoline substituent, compounds 2–6 have not been reported before according to literature searches. Compound 1 was already described as an intermediate in the chemical total synthesis of micacocidin [35], but has not been isolated from a natural source before. Conclusion In summary, six

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

• is an improved extension of our pervious protocol with arylboronic acids and provides access to enantioenriched α-arylglycines with an improved substrate diversity. It can be used for the direct synthesis of peptide-like building blocks, which can find direct application in the total synthesis of

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

• ]oxepine derivatives 101 (Scheme 21). Lin et al. [62] used copper-catalysed coupling in their total synthesis of bulbophylol-B (105), a substituted dihydrobenzo[b,f]oxepine. The authors synthesised an intermediate stilbene via Wittig reaction, followed by hydrogenation to give dihydrostilbene 104, which

• , prepared by benzylic bromination of the methyl substituents of 132 and 133 (Scheme 29). 5 1,4-Michael addition Narita et al. [72] reported their total synthesis of bauhinoxepine J (139), a quinone dihydrobenzoxepine derivative, by means of a base-promoted intramolecular etherification (Scheme 30). 6

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

• . Short information on applications in total synthesis is also given. Keywords: asymmetric catalysis; conjugate addition; electrophile; enolate; tandem reaction; Introduction The formation of complex chiral molecules is a crucial task of organic synthesis that enables the synthesis of pharmaceuticals

• . Application in total synthesis As shown before, asymmetric tandem conjugate additions followed by enolate trapping are robust methodologies for synthesizing complex structures with multiple stereogenic centers. For this reason, such stereoselective procedures are commonly used in total synthesis (Figure 2

• -catalyzed conjugate addition and subsequent trapping of the zinc enolate by acylation or aldol reaction with an overall yield of 71–78% and good stereoselectivity (Scheme 57) [105][106][107]. Recently, Poock and Kalesse demonstrated the first total synthesis of halioxepine, a meridoterpene isolated from the

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• oxanorbornenes; however, the latter two substrates did not undergo dehydrogenation, generating cis-selective annulated coumarins (10b and 10d). In 2006, the same group applied this methodology for the total synthesis of arnottin I (10h), a coumarin-type natural product isolated from the bark of the Xanthoxylum

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

• synthetic methodology developments and to natural product isolation or biosynthesis. Thus, thematic issues dealing with total synthesis in the Beilstein Journal of Organic Chemistry have naturally been published in these fields, such as "Transition-metal and organocatalysis in natural product synthesis

• syntheses ever published in the Beilstein Journal of Organic Chemistry, such as those of frog indolizidine alkaloids [5][6]. However, no thematic issue specifically related to total synthesis has been published before, and we thought it would be time to fill this gap. Although innovative developments are

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

• alternative experimental strategies to achieve the target molecule, as will be discussed further in this review. 2.3 Synthesis of combretastatins D series Boger and co-workers were the first to report the total synthesis of compound 2 using both routes A and B to obtain the desired macrolide [27]. Initially

• , employing a 10-step synthetic route with an overall yield of 9%. Nishiyama employed electrochemical techniques as a starting point to achieve the total synthesis of combretastatin D-4 (4) [54]. Different anodic oxidation conditions and phenolic substrates were tested aiming at the formation of a diaryl

• ether using Pd/C and ammonium formate (Scheme 21). With this synthetic route, the authors achieved the total synthesis of combretastatin D-4, after 12 reaction steps with an overall yield of 11%, highlighting the efficient formation of the diaryl ether 102 in 61% yield without the use of metallic

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

• cyclooctane ring fused to a cyclopentane ring, i.e., a [5-8] bicyclic ring system. This review focuses on the different strategies elaborated to construct this [5-8] bicyclic ring system and their application in the total synthesis of terpenes over the last two decades. The overall approaches involve the

• bicyclic system. This review focuses on the different strategies elaborated to build this [5-8] bicyclic ring system and their applications in the total synthesis of terpenes over the last two decades [3]. We are not providing here a comprehensive collection of the literature. When appropriate, the reader

• [20]. Its total synthesis was explored by Srikrishna and Nagaraju in 2012 using a linear strategy (Scheme 4) [20]. Thus, menthene 25 was converted in 16 steps into cyclopentane 26 presenting two unsaturated lateral chains. This compound was then treated with G-I catalyst to give the corresponding [5-8

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

• The total synthesis of racemic incarvilleatone has been achieved by utilizing unexplored accelerated Rauhut–Currier (RC) dimerization. The other key steps of the synthesis are oxa-Michael and aldol reactions in a tandem sequence. Racemic incarvilleatone was separated by chiral HPLC and the

• (±)-rengyolone (3). Despite of these syntheses, the synthesis of the dimeric natural product (±)-incarvilleatone (1), whose monomeric unit (±)-rengyolone (3) was connected by accelerated intermolecular Rauhut–Currier (RC) reaction was not reported in literature. Herein, we present the total synthesis of

• achieved the total synthesis of (±)-incarvilleatone (1) starting from rac-rengyolone (3) through accelerated RC intermolecular dimerization catalyzed by TBAF to synthesize a heterochiral dimerized product (±)-4, followed by a one-pot oxa-Michael and aldol reaction sequence using KHMDS as a base. The

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

• planar structure of 56 was concluded by Pliva and Šorm [128]. After the absolute configuration of 61 was solved [129], the full stereostructure of 56 became known. No total synthesis and no NMR data are available for 56. β-Guaiene is one of the main constituents of the essential oil from Achillea

Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris

• Angelique Ladwig,
• Markus Kroll and
• Stefan Schulz

Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16

• -isopropyl-1,6-dimethyl-1,2,3,4,4a,7,8,8a-octahydronaphthalen-1-ol (R-14) as part of the semiochemical mixture released by gular glands of the African reed frog Hyperolius cinnamomeoventris. This establishes the importance of sesquiterpenes for reed frogs, alongside macrocyclic lactones [2]. The total

• synthesis and characterization showed that this compound is the opposite enantiomer of 14 known from plants. This may indicate biosynthesis in the frog, but more work has to be performed to establish this. Furthermore, a short diversity-oriented synthesis based on the work of Taber and Gunn [13] enabled

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• constitutes an extremely powerful tool in total synthesis. In order to reach sustainable and economically appealing conditions, the quest for the substitution of palladium by non-noble metals has been investigated for more than four decades. To address this issue, new eco-friendly synthetic routes relying on

• functionality indeed affords the terminal oxidized function of the pheromone molecule (alkoxy acetate in 2 or 3, Scheme 4a and 4b, or formyl group in 1, Scheme 4c). As a representative target, we developed the total synthesis of the codling moth sex pheromone, (8E,10E)-dodecadien-1-ol (4), featuring the

• pheromone 4 can be obtained in a convergent total synthesis with a key iron-mediated cross coupling starting from sorbic acid and a commercially available α,ω-chloroalcohol in 4 steps, with an overall 38% yield. This method can also be used for the alkylation of dienyl bromides by classic aliphatic or