Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• correlations linking three different fragments. Compound 1 features three stereogenic centers at C-2, C-3, and C-16. The relative configuration of C-2 and C-3 was determined as (2R*,3R*) by 1H-1H NOESY correlations (Figure 3), while the relative configuration of C-16 remains unresolved due to the

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• stereogenic centers in compound 1 as 1R, 2R, 3R, 6R, 7R, 8S. This is likely the first characterized crystal structure of an ovalicin-type sesquiterpenoid. The molecular formula of pseudallene B (2) was assigned as C15H26O5S (three unsaturations), with one CH2 unit less than 1, based on positive HRESIMS data

• of 0.048(7), which suggested all the stereogenic centers in compound 2 as 1R, 2R, 3R, 6R, 7R, 8S. In addition to compounds 1 and 2, three related ovalicin-type sesquiterpenoid derivatives 3 [10], 4 [11], and chlovalicin (5) [12][13] were isolated and identified from the fungus P. boydii CS-793. It

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• . Asymmetric anion–π catalysis of intrinsically disfavored exo-selective Diels–Alder reactions on fullerene catalyst 21, with notional endo and exo transition states VI and VII, respectively. Asymmetric anion–π catalysis to install remote stereogenic centers on fullerene catalyst 21, with notional transition

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• -workers [61] extended the application of NHC–copper catalysts to the conjugate addition of boronates to acyclic α,β-unsaturated carboxylic esters, ketones, and thioesters leading to the enantioselective formation of boron-substituted quaternary carbon stereogenic centers (Scheme 43). All transformations

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

• last step involves the enamine intermediate which drives an intramolecular aldol condensation to form the final product 5. In this elegant cascade process, catalyst 1 promotes three consecutive carbon–carbon bond forming steps generating four stereogenic centers with high diastereoselectivity and

• simple flash chromatography. Conclusion An unprecedented methodology for the synthesis of 4,6-disubstituted 5-nitrocyclohexene carbaldehydes with three contiguous stereogenic centers using acetaldehyde as one of the reaction components of an Enders cascade reaction has been developed. The masked form of

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• construction of stereogenic centers using polar organometallics [1]. In this way, 1,4-additions of typical organometallics such as dialkylzinc, Grignard reagents, and trialkylaluminum have been developed [2][3][4][5][6][7][8][9]. Recently, also Cu-catalyzed conjugate additions of organozirconium [10][11] or

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

• . 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

• contains six contiguous stereogenic centers out of which four are all-carbon quaternary stereocenters. The authors have achieved the stereoselective synthesis of waihoensene for the first time with a 3.8% overall yield (15 steps) (Scheme 59). The construction of the triquinane core included a Cu-catalyzed

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

• analogue synthesis, starting from (+)-β-citronellene. Key stereoselective transformations involve an asymmetric Krische allylation, an aldol reaction under 1,5-anti stereocontrol, and a Tishchenko–Evans reduction accompanied by a peculiar ester transposition, allowing to install key stereogenic centers of

• of an unsaturated fourteen- or sixteen-membered macrolactone decorated by an ʟ-cysteine-derived 2-oxo-1,3-thiazolidin-4-yl substitutent, and the presence of five stereogenic centers forming a 1,2,4,6,9-stereopentade (Figure 1). In latrunculins A (1) and B (2) three of them are embedded in a lactol

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

• Martin Kalník,
• Sergej Šesták,
• Juraj Kóňa,
• Maroš Bella and
• Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

• configurations of all its stereogenic centers match those of swainsonine. Furthermore, DIM is a micromolar GMII inhibitor, which is easily accessible on a large scale from ᴅ-mannose by well-established methods [15][29]. In general, improvements of physicochemical and inhibitory properties of monocyclic

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

• compound 24 was rationalized by an isomerization of the double bond prior to the cyclization step. Isolated from the Ecuadorian liverwort Anastrophyllum auritum in 1994, ent-fusicoauritone (28) is a diterpene presenting a fusicoccan skeleton with a β-hydroxyketone on the A-ring and 5 stereogenic centers

• backbone with 8 fused rings, a unique [7-8] bicyclic motif, an oxa-bridge over the cyclooctane ring, and the presence of 12 stereogenic centers [36]. The strategy proposed by the authors was to carry out a RCM reaction to elaborate the cyclooctene ring from functionalized intermediate 66, prepared as a

• -8-6-5] tetracyclic all-carbon system with 10 stereogenic centers (Scheme 15). This natural product was isolated from two Gentianella plant species, namely G. nitida and G. alborosea used in Peruvian traditional medicine. The first report of its synthesis was given in 2014 by Hog and co-workers [46

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

• a stereocontrolled manner. Stereogenic centers on the ethylenedithiol tethering group can give modest levels of stereoinduction (Scheme 11b), despite the relatively remote relationship between the stereogenic centers [60][61]. Guaragna, Palumbo, D’Alonzo and co-workers have very productively used

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

• and final dehydration by Burgess reagent provided the total syntheses of magninoids A (104) and C (103, Scheme 8). Divergent total synthesis of crinipellins (Xie and Ding 2022) [53]: Crinipellins are highly congested tetraquinane natural products comprising 6–10 stereogenic centers, three of which are

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• aminobisabolene sesquiterpenoid halichonic acid ((+)-1) from the sponge Halichondra sp. (Figure 1) [4]. This amino acid natural product features a rigid 3-azabicyclo[3.3.1]nonane ring system containing four stereogenic centers within the piperidine ring. In 2021, the same group re-isolated (+)-1 from the sponge

• Axinyssa sp. along with the structurally related compound halichonic acid B ((+)-2) [5]. Structurally, (+)-2 is a pipecolic acid derivative containing a cyclohexenyl ring as a substituent group. This compound also features four stereogenic centers (three of which are located within the piperidine ring) and

• the resulting tertiary carbocation to occupy equatorial positions (14), establishing the observed trans-relationship between these groups while simultaneously setting two new stereogenic centers. As before, one can envision several different fates for the tertiary carbocation present in 14. Although

Synthetic study toward the diterpenoid aberrarone

• Liang Shi,
• Zhiyu Gao,
• Yiqing Li,
• Yuanhao Dai,
• Yu Liu,
• Lili Shi and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2022, 18, 1625–1628, doi:10.3762/bjoc.18.173

• tetracyclic carbon skeleton yet-to-be found in Pseudopterogorgia elisabethae species, although related cyclohexane-angularly-fused triquinane systems have been found in waihoensene (3), conidiogenone (4), lycopodium alkaloids magellamine (5) and lycojaponicumin C (6) (Figure 1). Its seven stereogenic centers

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme

• Jia-Hua Huang,
• Jian-Ming Lv,
• Liang-Yan Xiao,
• Qian Xu,
• Fu-Long Lin,
• Gao-Qian Wang,
• Guo-Dong Chen,
• Sheng-Ying Qin,
• Dan Hu and
• Hao Gao

Beilstein J. Org. Chem. 2022, 18, 1396–1402, doi:10.3762/bjoc.18.144

• stereogenic centers at C2, C6, C10, and C14 introduced during the two cyclization steps, FC-type diterpene synthases (DTSs) could be divided into 16 subtypes [20]. Furthermore, considering the modes of potential carbocation rearrangement and final carbocation quenching, there might be more FC-type DTSs in

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• -tricarbonyl compound 108 to set two stereogenic centers and correct one via an intramolecular aldol addition (108 → 109; Scheme 18) [34]. The vic-tricarbonyl compound 108 was synthesized via DMDO oxidation from α-diazo-β-ketoester 107, which was easily accessible from 5-methoxy-4H-chromen-4-one (106). The

Enzymes in biosynthesis

• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1131–1132, doi:10.3762/bjoc.18.116

• proceed through multistep cationic cascade reactions and usually produce a polycyclic terpene hydrocarbon or alcohol with multiple stereogenic centers. While these transformations require only a single enzyme, polyketide and nonribosomal peptide biosyntheses are catalyzed by megasynthases that follow an

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• configuration determination of natural products with stereogenic centers near the chromophore groups [20], was applied, since there is an α,β-unsaturated ketone chromophore nearby C-5 and C-2 in compound (+)-1. Thus, the theoretical ECD spectrum of (+)-1 was calculated by the DFT calculation method at the b3lyp

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• diastereomer 2a is indicative of a sequence of concerted processes with an unambiguous stereochemistry control at each step where stereogenic centers are formed. Dibenzoazulenodipyrroles 2 have a pronounced three-dimensional character which make this chemotype promising as probe for protein–protein

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• , isolated from oils distilled from citronella plants, which is very effective as a repellent and antifungal. In the presence of Brønsted or Lewis acids (S)-citronellal undergoes an intramolecular carbonyl–ene cyclization reaction forming two new stereogenic centers, which turns out into four possible

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• because they can serve as key synthetic intermediates in the construction of complex natural products [17][18][19][20][21][22][23]. Particularly challenging is the placement of the two C3/C3’ contiguous quaternary stereogenic centers, just as they are found in various alkaloids, such as those belonging to

• space group P212121. The presence of sulfur anomalous scatters allowed to unequivocally establish the absolute configurations, which reads S at the chiral center C2 and R at the C10 (C numbering as in Figure 1). The absolute configuration of the two sulfur stereogenic centers is confirmed to be R

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

• Zsanett Benke,
• Attila M. Remete and
• Loránd Kiss

Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132

• multiple stereogenic centers. The synthesis involved selective cycloadditions, with subsequent ROM of the formed cycloalkene-fused isoxazoline scaffolds and selective CM by chemodifferentiation of the olefin bonds of the resulting alkenylated derivatives. Various experimental conditions were applied for

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• stereogenic centers. Review A plethora of highly effective small‐molecule organocatalysts have enriched the field of organic synthesis [27], including chiral proline derivatives, N‐heterocyclic carbenes, chiral thioureas and Brønsted acids as well as phase‐transfer catalysts (PTC), such as the quaternary

• dihydrocinchonine 26 in combination with trifluoracetic acid (TFA) as Brønsted acid [39]. The reaction provides pyranocoumarins 25 with three vicinal stereogenic centers in high regio-, diastereo- and enantioselectivities through a tandem allylic alkylation/intramolecular oxa-Michael addition (Scheme 7). A

• /indandione-fused spirocyclopentanes 104 bearing four contiguous stereogenic centers, was described by Chen et al. [68]. This transformation was catalyzed by a cinchona-thiourea derivative 105 furnishing the spiro compounds with good to high yield and enantioselectivity (Scheme 33). In this method two

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• synthesis of new bioactive compounds [1][2]. A careful view of the carbon backbone of these natural molecules reveals their high molecular complexity [3][4][5], which can be described by the presence of multiple stereogenic centers in the same molecule, a substantial fraction of sp3 hybridized carbons (Fsp3

• stereogenic centers were constructed by this cascade reaction. As exemplified above (Scheme 23), the hypothesized enolate intermediate produced in the radical conjugate addition promoted by a MHAT process could be engaged in sequential reactions, offering a range of possibilities for the design of new

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• . Starting imine 135 with two well-defined stereogenic centers at the hydrocarbon backbone were prepared as a mixture of (RS)- and (SS)-diastereoisomers from ᴅ-glutamic acid. After nucleophilic addition to the imine, a successive cyclization–desulfinylation occurred to give the corresponding piperidinone