CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• ↔142’ (Scheme 35). Oxygen-stabilized α-(trifluoromethyl)carbenium ions (oxocarbenium ions) have been exploited for chemical synthesis [92][93][94]. Ketone 143a and ketoxime 143b undergo Friedel–Crafts reactions in the presence of Brønsted or Lewis acid to furnish the corresponding CF3-containing

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• this precursor in (−)-adaline, supporting fatty acid origin for this alkaloid. Reflex bleeding is costly due to energy expended in chemical synthesis and fluid loss. Therefore, it is only deployed when other strategies have failed, and the ladybird is in severe danger [35][36]. A massive discrepancy in

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• consisting in the chemical synthesis of N7-methyl derivatives of guanosine (N7Me-Gua) [30][32][33][34][35] and 2'-deoxyguanosine (N7Me-dGua) [31][34][36][37], and the desired Rib-1Pi and dRib-1Pi were obtained in high yields [35][36][37]. The final aim of these studies was the synthesis of biologically

• in cladribine synthesis The dual function of QAE Sephadex A-25 noted above was tested in the enzymatic synthesis of cladribine using dRib-1Pi as a barium salt and bound to the resin. Chemical synthesis of this nucleoside, which has a wide spectrum of pharmacological activities [6][63][64][65], is

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• intrinsic kinetics. This would reduce the reactor size and downstream the processing costs while increasing the safety. The design considerations for microreactors that aim at large-scale chemical synthesis are significantly different from the lab-on-a-chip concept. While gathering intrinsic kinetic data

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• from biofermentation, chemical synthesis, and solvent extraction processes. In addition, these plans are compared and ranked according to Borda count and poset (partially ordered set) pairwise dominance analyses using the following attributes: process mass intensity (PMI), sacrificial reagent (SR

• vanillin since this high commodity flavour chemical is ideally suited to the present investigation owing to its varied methods of synthesis spanning classical chemical synthesis, biofermentation, and solvent extraction procedures from the natural source vanilla beans. We chose these particular examples

• ][28][29][30]; five plans involved chemical synthesis from wood-derived starting materials (lignosulfonic acid liquor or sawdust) [31][32][33][34][35][36][37]; seven plans involved chemical synthesis from either fossil-fuel or natural product-derived starting materials (guaiacol, eugenol, isoeugenol

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• , light is inexpensive, nontoxic, noncontaminating, ample (or “limitless” in the case of sunlight) and a renewable source of energy for environmentally-friendly and “green” chemical synthesis. As a consequence of comprehending the detrimental impact of human industry on the environment, new methods to

Synthesis of monophosphorylated lipid A precursors using 2-naphthylmethyl ether as a protecting group

• Jundi Xue,
• Ziyi Han,
• Gen Li,
• Khalisha A. Emmanuel,
• Cynthia L. McManus,
• Qiang Sui,
• Dongmian Ge,
• Qi Gao and
• Li Cai

Beilstein J. Org. Chem. 2020, 16, 1955–1962, doi:10.3762/bjoc.16.162

• disaccharide lipid A precursor 2 (as triethylammonium salt) was obtained in 88% yield. Conclusion As described, we have developed an efficient approach for the chemical synthesis of two monophosphorylated lipid A precursors. Lipid X (1) could be prepared from the common building block 15 via deprotection

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• Bern, Switzerland Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, 10065 New York, United States of America 10.3762/bjoc.16.145 Abstract The chemical synthesis of molecular probes to identify and study membrane proteins involved in the biological pathway of protein

• and the availability of the required mannosyltransferase. Here, we describe a purely chemical approach to synthesize a photoclickable MPD analog containing β-ᴅ-mannose (in MPC-1). The chemical synthesis allows for a rapid upscaling of the reactions if necessary. In addition, having access to the

• -1 and MPC-2, 1JCH values 158 Hz and 161 Hz, respectively, were obtained (for comparison, for MPC-3 containing almost exclusively the α-anomer, a value of about 171 Hz was determined, see Supporting Information File 1). As highlighted above, the most important step in the chemical synthesis of the

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• synthetic strategies. Such examples in recent years include olefin metathesis [1] as well as C–C and C–N coupling reactions [2], among the most obvious examples. While these reactions undoubtedly had very significant impacts on the development of much cleaner and efficient chemical synthesis strategies, the

Synthesis of new asparagine-based glycopeptides for future scanning tunneling microscopy investigations

• Laura Sršan and
• Thomas Ziegler

Beilstein J. Org. Chem. 2020, 16, 888–894, doi:10.3762/bjoc.16.80

• strategy with NH3 in MeOH allowed the crude product to precipitate directly from the reaction mixture, followed by the isolation through simple filtration. After washing the residue with petroleum ether, the compounds 10 and 11 were obtained in pure form. Conclusion We described the efficient chemical

• synthesis of a series of new glycopeptides containing asparagine, tryptophane, alanine, and phenylalanine linked to various saccharides, such as glucose, galactose, mannose, cellobiose, lactose, and maltose. We further compared two common peptide coupling procedures that use HBTU and HATU, respectively. We

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• chemical synthesis details can be found in Supporting Information File 1. HDAC8 enzymatic activity assay A fluorogenic assay (BPS Bioscience, catalog # 50008) was performed to evaluate the inhibition potential of the designed inhibitors. The assay was carried out using the supplier’s instructions. TOI1

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• , De Meo and co-workers have reported the significant effect of O-substituents on atom C-7 on the reactivity of thiosialoside donors and on the anomeric stereoselectivity of chemical sialylations [21]. Thus, 2,7-anhydro-Neu5Ac can serve as a promising building block for the chemical synthesis of

• backbone of Neu5Ac. Thus, the aim of this study was to cleave the ring of the 2,7-anhydro derivatives with a choice of suitable Lewis acids as catalysts in order to utilize the acetolysis products as building blocks for the chemical synthesis of Neu5Ac-containing glycans. Results and Discussion It is known

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

• Enrique A. Del Vigo,
• Carlos A. Stortz and
• Carla Marino

Beilstein J. Org. Chem. 2019, 15, 2982–2989, doi:10.3762/bjoc.15.294

• amounts of carbohydrate-containing molecules. Due to the chemical nature of carbohydrates, with multiple possible linkage positions giving rise to different regioisomers, with two possible anomeric configurations, the chemical synthesis of complex oligosaccharides is difficult and a rather time-consuming

Automated glycan assembly of arabinomannan oligosaccharides from Mycobacterium tuberculosis

• Alonso Pardo-Vargas,
• Priya Bharate,
• Martina Delbianco and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2019, 15, 2936–2940, doi:10.3762/bjoc.15.288

• chemical synthesis of AM is an attractive alternative. AM polysaccharides as large as 92-mers as well as many shorter AM oligomers have been prepared by solution-phase synthesis [16][17][18][19][20]. These multi-step syntheses are challenging and time-consuming. AGA reduces time and effort to access

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

• sarcosine (Sar) and derivatives. Chemical synthesis of the native sequence ᴅ-Ala-Dha-Sar thioester required revision of the sequential peptide synthesis into a convergent strategy where the thioester with sarcosine was formed before coupling to the Dha-containing dipeptide. Keywords: antibiotic; argyrin

• G reveals that the antibiotic is deeply buried inside the protein’s binding pocket and only a few sites of the molecule can possibly be modified without introducing steric clash with the binding site. Besides the methoxytryptophan which has been addressed by chemical synthesis, one appealing

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• designed our photoprobe to take full advantage of high thermodynamic stability of the cis configuration of 4FAB, thus our probe can be pre-set to ON or OFF and used for extended periods without change of function. Experimental Chemical synthesis Full experimental synthetic details can be found in

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

• linked with a bouquet of methods to broaden the platform of molecules with favourable olfactory properties. These include chemical synthesis, microbiology and molecular biology associated with biotechnology and combinations based on these methods. Hence also the most recent developments in synthetic

Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside

• Debasish Pal and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2019, 15, 2563–2568, doi:10.3762/bjoc.15.249

• Debasish Pal Balaram Mukhopadhyay Sweet Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia 741246, India 10.3762/bjoc.15.249 Abstract The total chemical synthesis of the pentasaccharide repeating unit of the O-polysaccharide

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

• José Brango-Vanegas,
• Luan A. Martinho,
• Lucinda J. Bessa,
• Andreanne G. Vasconcelos,
• Alexandra Plácido,
• Alex L. Pereira,
• José R. S. A. Leite and
• Angelo H. L. Machado

Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247

• represent standard deviations. Cell viability of human fibroblast exposed to compounds 9e (A) and 9g (B) for 24 and 48 hours. The values are expressed as mean ± SEM. ****p < 0.0001, **p < 0.005 and ***p < 0.001 versus DMEM control group. Macrocyclization strategy based on SN2’. Chemical synthesis of the MBH

• adducts 2 and their carboxylic acids 3. Chemical synthesis of the linear peptidomimetics 8. Macrocyclization strategy based on SN2’ reaction to affords the solonamide analogues 9 and their overall yields based on the initial resin’s molarity. Halos of hemolysis or inhibition of hemolysis of S. aureus ATCC

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• improved mismatch discrimination under physiological conditions than natural ones. Furthermore, PNAs have a straightforward chemical synthesis by Fmoc-based PNA solid-phase synthesis and remarkable stability against nuclease- and protease-mediated degradation [32][33]. In regard to all these beneficial

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

• engineering to optimize product ratios or to alter the native product portfolio of the enzyme [9][26][27]. Furthermore, production by engineered microorganisms considerably reduces the cost compared to total chemical synthesis or extraction from natural sources, since the target compounds are produced from

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

• increase the nucleophilic character, and stabilise the fulvene system (see dipolar forms in Scheme 1). Similar results have been observed by other groups [32][96][124][203]. Whilst many of the documented reactions focus on chemical synthesis and characterisation rather than applications, several

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• guest receptors [4][5]. Planar-chiral macrocyclic molecules are particularly interesting in the context of the host–guest complexation properties [6][7][8]. Pillararenes are typical examples of this type of compounds and have attracted considerable attention due to their facile chemical synthesis and

Mechanochemistry II

• José G. Hernández

Beilstein J. Org. Chem. 2019, 15, 1521–1522, doi:10.3762/bjoc.15.154

• strategy for the future of chemical synthesis. In fact, the potential of mechanochemistry in various domains of research, industry and in commercial entities has been recently recognized by the IUPAC after the inclusion of mechanochemistry among the ten chemical innovations that will change our world [2

Efficiency Eff_syn of complex syntheses as multicomponent reactions, its algorithm and calculations based on concrete criteria

• Heiner Eckert

Beilstein J. Org. Chem. 2019, 15, 1425–1433, doi:10.3762/bjoc.15.142

• . Comprehensive efforts are being undertaken in this field, including in large workshops, e.g., [1]. The efficiency of synthesis forms the core for the evaluation of innovations within synthesis chemistry [2][3][4][5][6] and is the indispensable requirement for a radical simplification of chemical synthesis [3

• ]. Concrete and reliable criteria must be available for this purpose, criteria that can be easily determined and measured, and which can also form the basis for an algorithm. The standard evaluation of a chemical synthesis is traditionally based on the overall yield yoa. This is the product of all sequential

• : novel MCR as key step in total synthesis of (+)-20S-camptothecin Another typical example for the simplification of a complex chemical synthesis [2][3] is the total synthesis of the extremely potent antitumor agent (+)-20S-camptothecin (3), which has been a highly effective agent for decades now. This