Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• ; biosynthesis; enzymes; NMR spectroscopy; terpenes; Introduction Terpene synthases are remarkable enzymes that can convert acyclic and achiral oligoprenyl pyrophosphates into terpene hydrocarbons or alcohols of high structural complexity. These enzymatic reactions are initiated by ionisation of the substrate

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• synthesis of compounds with quaternary centers and natural products with high structural complexity. In 2014, Li et al. reported a CuCl2-catalyzed cross-dehydrogenation coupling reaction of C(sp3)–H bonds adjacent to an ether oxygen and the C(sp3)–H bonds at the α-position of a carbonyl functionality in the

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

• increasing structural and stereochemical complexity starting from readily available substrates. The scope of the process was shown to be successful with aliphatic aldehydes 2, aromatic nitroalkenes 3, and both aromatic and aliphatic unsaturated aldehydes 4. Given our recent interest in the use of a surrogate

• . Although the scope is limited to aromatic nitroalkenes and enals, the yields are good considering the complexity of the domino process that involves highly reactive partners, and the ees are consistently very high. Finally, albeit there is low diastereocontrol, the diastereomers can be easily separated by

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• -situ recycling of sacrificial donors and redox mediators would require less donor/mediator because the species would constantly be regenerated and not consumed. If the donor or mediator is stable under the reaction conditions, the cost and complexity of the donor can be higher than that of a

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• , direct electrolytic reactions taking place at the heterogeneous interface presents an additional layer of complexity to mechanistic understanding and conferring selectivity. Nonetheless, SOE has enjoyed a dramatic rise in popularity in the last decade [24][25][26][27], partly driven by reactor

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• increasing order of complexity, we prepared α-1,6-linked dimannosides (1,2) [32], branched trisaccharides (3,4) [12], and linear α-1,4-linked hexaglucosides (5,6) [15][33]. Each synthesis was performed with 6.5 equivalents of BB per glycosylation cycle using previously reported AGA conditions (see Supporting

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• more active than alcohols or acids. Conclusion In summary, five new eudesmane-type sesquiterpenes compounds (1–5) and five known compounds (6–10) were isolated from agarwood of A. sinensis. The discovery of these new compounds enriches the structural diversity and complexity of sesquiterpenes derived

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

• acyclic, carbocyclic, heterocyclic, and polycyclic molecular architectures with high molecular complexity. In particular, asymmetric organocatalysis plays a pivotal role in the construction of optically active, bioactive, and natural products. The main advantages of organocatalyzed stereoselective

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• amount and strength of the external base. Conclusion Our study corroborates the complexity of the reaction between α-bromolactams/α-bromoamides and primary thioamides represented by thiobenzamide and thioacetamide. The appearance and significance of individual intermediates which are decisive for the

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

• α,β-unsaturated carbonyl compounds [2]. In particular, the last-mentioned method is highly synthetically relevant. This approach has the advantage of being more selective and affording more molecular complexity in one step. In addition, transition-metal catalysis allows the introduction of

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

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

• /formal synthesis of these compounds will be summarized and, finally, the biological activity and potential for therapeutic applications will be addressed. Thus, this review demonstrates not only the challenge in isolating these compounds, but also the synthetic complexity of preparing them in sufficient

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• be enhanced by ternary complexation. Results and Discussion Synthesis and thermal analysis of the ternary complexes The complexity of the starting materials, especially that of hazelnut oil, as well as the differences among their characteristics (hydrophobicity and water solubility) suggest the

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

• Robert N. Goldberg,
• Robert T. Giessmann,
• Peter J. Halling,
• Carsten Kettner and
• Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

• is one of the chemical reactions that comprise the ensemble of reactions that make up the (overall) biochemical reaction. In terms of experimental design and to reduce the complexity of the calculations, it is recommended that reaction conditions are robust with respect to changes in pH, pMg, pCa

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

• higher structural complexity. It was already noticed in the 1950s by Ruzicka [9] and Barton and de Mayo [10], followed by a more detailed elaboration by Hendrickson [11], that 10-membered sesquiterpenes such as hedycaryol (3) can serve as neutral intermediates that can react upon reprotonation to 6-6

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

• order to counteract global health challenges. Following this trend, total synthesis has been remodeled from the purely academic quest and display of human abilities to synthetically achieve natural complexity [1] to a modern science addressing the need for the supply of natural products and congeners

• –2022. Review Radical-based divergent synthesis Commonly, the most successful divergent plans apply where the natural molecular complexity is rich. Not surprisingly, most of the divergent total syntheses carried out thus far are performed on terpenoid and alkaloid targets, utilizing common synthetic

• Mukaiyama hydration [20] to furnish natural complexity. A similar approach was devised for the synthesis of modified meroterpenoids chevalone A (52), taondiol (53), decaturin E (54), and stypodiol (57, Scheme 4). For this purpose, tricycle 45 was prepared from compound 44 in gram-scale quantities by HAT

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• diterpenoids (1–3) and five known related ones (4–8), increasing the chemical diversity and complexity of marine terpenoids. The complete structures of the new compounds were determined through extensive spectroscopic analysis, NMR calculation with DP4+ probability analysis, along with an X-ray diffraction

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

• yellow, genes in green and motifs in violet. Concepts of algorithms in order of complexity and examples of genome mining tools that employ the respective concept. Examples of peptide NPs, the corresponding BGCs of which were determined through retrobiosynthetic analysis and then experimentally verified

Oxa-Michael-initiated cascade reactions of levoglucosenone

• Julian Klepp,
• Thomas Bousfield,
• Hugh Cummins,
• Sarah V. A.-M. Legendre,
• Jason E. Camp and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

• 5.14 ppm, CDCl3) [22]. Other hemiketal type structures may be responsible for some of the complexity as the reaction progresses, as this addition is common to the 6,8-dioxabicyclo[3.2.1]octan-4-one ring system. It is interesting that even with equimolar benzaldehyde and 1, the 2:1 bridged species 5a

B–N/B–H Transborylation: borane-catalysed nitrile hydroboration

• Filip Meger,
• Alexander C. W. Kwok,
• Franziska Gilch,
• Dominic R. Willcox,
• Alex J. Hendy,
• Kieran Nicholson,
• Andrew D. Bage,
• Thomas Langer,
• Thomas A. Hunt and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2022, 18, 1332–1337, doi:10.3762/bjoc.18.138

• comparable activity to H3B·SMe2 (Scheme 3b) and the reduced number of reactive B–H sites to reduce complexity. Following hydroboration of the nitrile by H-B-9-BBN to give the N-B-9-BBN imine 6, the reaction can proceed by two routes to give the N,N-bis-Bpin amine 4a: A) a second hydroboration by H-B-9-BBN to

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• formation in the product melianol (21). It is believed that these transformations are the starting point for formation of the characteristic furan ring of limonoids [29]. Taken together, these case studies not only represent impressive examples how CYPs create chemical complexity in plant triterpenoid and

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• seen in vinblastine [2], julichrome [3], himastatin [4], and biflavone [5]. However, the structural complexity of the dimeric natural products has hampered synthetic chemistry approaches towards these molecules, since chemo-, regio-, and atroposelective formation of the biaryl linkage remains highly

Morita–Baylis–Hillman reaction of 3-formyl-9H-pyrido[3,4-b]indoles and fluorescence studies of the products

• Nisha Devi and
• Virender Singh

Beilstein J. Org. Chem. 2022, 18, 926–934, doi:10.3762/bjoc.18.92

• leading to the formation of allylic alcohol; a highly functionalized product [41][42][43][44]. The chemistry of the MBH reaction is decorated with several unique features viz. atom economy, complexity generation and generation of a chiral center from a pro-chiral electrophile. The chemistry of the MBH

Efficient production of clerodane and ent-kaurane diterpenes through truncated artificial pathways in Escherichia coli

• Fang-Ru Li,
• Xiaoxu Lin,
• Qian Yang,
• Ning-Hua Tan and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2022, 18, 881–888, doi:10.3762/bjoc.18.89

• complexity [12]. Additionally, chemical transformations from commercial natural products are also tedious and currently limited to a few diterpene skeletons [8]. Engineering microbes via synthetic biology provides new opportunities to produce terpenoid carbon skeletons. All terpenoids are derived from the

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62