The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• sections. Similarly, Pertel and co-workers also demonstrated the use of 2-(2,2,2-trichloroethoxy)-2-oxazoline glycosyl donor 22 (Scheme 4) which could be used for stereo- and regioselective glycosylations using extremely mild conditions [94] and requiring low concentrations of the catalyst. In this case

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• alkene forms the oxazoline A, and SN2 substitution with the fluoride ion displaces iodotoluene to form the product. An electrochemical approach was also reported by Lennox and co-workers for the synthesis of chromanes 34 (Scheme 18) [42]. The authors reported using p-tolyl-difluoro-λ3-iodane 10, formed

• up to 95% within a short time-frame of 10 minutes. Treatment of N-(2-phenylallyl)benzamides with 10 equivalents of BF3·Et2O, iodobenzene, m-CPBA in dichloromethane (DCM) at 0 °C resulted in the formation of the oxazoline product (Scheme 21). DFT calculations indicated several steps in the mechanism

• synthesis of various halogenated 1,3-oxazine 50 and 2-oxazoline derivatives 51 using boron trihalides as the halogen source [6][49]. They found that the choice of halogen source influences the reaction outcomes. With the use of BCl3 (Scheme 28), N-cinnamylbenzamides 52 were transformed to give the

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• ], requires the presence of a nucleophile at the β-position of the amino acid and occurs exclusively on select amino acids. Specifically, cyclodehydration of a serine or threonine (followed by oxidation or reduction) generates an oxazole, oxazoline, or oxazolidine moiety in the NRP backbone, and the analogous

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• ]. The set of tert-butoxy A and tert-butylperoxy B radicals are formed from TBHP during the Cu(I)/Cu(II) redox cycle. The Cu(II)/TBHP system also provides oxidation of benzyl alcohol 80 to the corresponding aldehyde C. The reaction of isocyanate 81 with aldehyde C generates oxazoline D, HAT from D by the

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• (Scheme 1). The most promising catalyst scaffolds for the reaction under study were identified by volcano plot analysis [26][27]. Inspired by the asymmetric oxazoline synthesised by Gao et al. [28], and guided by the volcano plot results, modifications to these FLP scaffolds facilitated the development of

• ]. One study reported a reaction involving the asymmetric reduction of ketones using an achiral borane, denoted as B(p-HC6F4)3, paired with a chiral oxazoline, as depicted in Scheme 3 [28]. Remarkably, in this study, these FLPs demonstrated the capability to achieve high conversion rates and enantiomeric

Hypervalent iodine-mediated cyclization of bishomoallylamides to prolinols

• Smaher E. Butt,
• Konrad Kepski,
• Jean-Marc Sotiropoulos and
• Wesley J. Moran

Beilstein J. Org. Chem. 2024, 20, 2455–2460, doi:10.3762/bjoc.20.209

• 2019, we reported our DFT study on the cyclization of N-allylbenzamide (1a) to the 2-oxazoline 4a, i.e., where n = 1 and Ar = Ph [18]. This work indicated that the alkene is activated by the iodine(III) species and that this triggers cyclization. Intrigued by the change in mechanism from O- to N

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• ) (Scheme 18). 17-Spiro-1,3-oxazoline steroids Jin et al. [37] described a series of spiro-1,3-oxazolines synthesized from the commercially available estrane derivative ethylene deltenone 24. This conjugated diene was regioselectively epoxidized at the 5(10) double bond to furnish compound 58

Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation

• Akanksha Chhikara,
• Fan Wu,
• Navdeep Kaur,
• Prabagar Baskaran,
• Alex M. Nguyen,
• Zhichang Yin,
• Anthony H. Pham and
• Wei Li

Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122

• ; lithium salt activation; olefin oxyamination; oxazoline; Introduction Hypervalent iodine(III) reagents, also known as λ3–iodanes, have been well established and used in organic synthesis for the past decades [1][2][3][4][5]. The pioneering works of Fuchigami and Fugita, Ochiai, Kita, and later the

• alkenes regioselectively to furnish their respective oxazoline regioisomer (Scheme 1d). Herein, we report that lithium salts such as LiBF4 or LiPF6, which are often used in lithium-ion batteries, can be used to activate hypervalent iodine catalysts to enable olefin oxyamination reactions with simple

• hypervalent iodine catalyst precursor, Selectfluor as the oxidant, and LiBF4 as the lithium salt for hypervalent iodine activation, we were gratified to observe the formation of the desired oxazoline 3 in 59% yield as the major regioisomer in nitromethane (MeNO2) solvent (Table 1, entry 1). To further improve

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• Ishihara et al. using chiral copper bis(oxazoline) (S,S-11) catalysts to provide optically active mandelic acid esters 9 [75]. Among the different catalysts employed, Cu(SbF6)2 in the presence of t-butanol and (S,S)-bis oxazoline (S,S-11), afforded the desired product in 71% yield and 54

• % enantioselectivity. They employed a double asymmetric induction with (+)/(−)-menthol (12), and CuX2 bis(oxazoline) catalyst where the corresponding chiral mandelate ester 13 was obtained in 81% yield and high selectivity (90% de) (Scheme 6). The proposed mechanism of the reaction is depicted below. Hong et al

• reaction of aryl glyoxals using Cr(ClO4)3 as catalyst. Cu(II)-PhBox-catalyzed asymmetric Cannizzaro reaction. FeCl3-based chiral catalyst applied for the enantioselective intramolecular Cannizzaro reaction reported by Wu et al. Copper bis-oxazoline-catalysed intramolecular Cannizzaro reaction and proposed

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• intermediate led to intramolecular cyclization. In 2020, electrophilic cyclization of allylic amides 134 using N-(phenylthio)succinimide 1 in the presence of camphorsulfonic acid (CSA) as a Brønsted acid and tetrabutylammonium chloride (TBAC) led to 5-[(phenylthio)methyl]oxazoline scaffolds 135 (Scheme 57) [89

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

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

• chelate environmental Fe3+. Ligand groups, such as hydroxamate, phenolate, catecholate, carboxylate, or oxazoline/thiazoline residues, confer siderophores their high affinity for the binding of Fe3+ [3][4][5]. Following the coordination of the metal, the Fe3+-loaded siderophore complex is transported back

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• Chemistry, Department of Chemistry and Helsinki Institute of Sustainability Science, Faculty of Science, University of Helsinki, PO Box 55, 00014 Helsinki, Finland 10.3762/bjoc.19.21 Abstract For about the last ten years, poly(2-oxazoline)s have attracted significant attention as potential material for

• biomedical applications in, e.g., drug delivery systems, tissue engineering and more. Commonly, the synthesis of poly(2-oxazoline)s involves problematic organic solvents that are not ideal from a safety and sustainability point of view. In this study, we investigated the cationic ring-opening polymerization

• of 2-ethyl-2-oxazoline and 2-butyl-2-oxazoline using a variety of initiators in the recently commercialized "green" solvent dihydrolevoglucosenone (DLG). Detailed 1H NMR spectroscopic analysis was performed to understand the influence of the temperature and concentration on the polymerization process

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• the presence of an oxazole or an oxazoline ring. Up to now, it is not clear whether these structural variations are biologically relevant in terms of iron sequestration and cellular uptake. Conclusion In summary, Nocardia altamirensis was found to synthesize various amamistatins under iron-deficient

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

• Yelong Lei and
• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6

• -2-yl)alkanamides and 1-(oxazolin-2-yl)alkylphosphonates. Keywords: aziridine; diazooxoester; diazo compound; ketene; oxazoline; ring expansion; Introduction Oxazoline derivatives are an important class of nitrogen and oxygen-containing five-membered unsaturated heterocycles [1] and widely exist in

• some natural products [2] and pharmaceuticals [3], such as in the antitumor epi-oxazoline halipeptin D isolated from marine organisms [4], in the cytotoxic natural depsipeptide brasilibactin A [5], and cyclohexapeptide bistratamide A [6] (Figure 1). Oxazoline is also one of the crucial coordinating

• synthesis of oxazoline derivatives [11][12]. They mainly include (1) cyclization of 2-amidoethyl halides or sulfonates, which are prepared from carboxylic acid derivatives and vicinal amino alcohols [8][9][10] (Scheme 1a); (2) direct condensation of carboxylic acid derivatives or nitriles with vicinal amino

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B

• Emmanuel T. Oluwabusola,
• Olusoji O. Adebisi,
• Fernando Reyes,
• Kojo S. Acquah,
• Mercedes De La Cruz,
• Larry L. Mweetwa,
• Joy E. Rajakulendran,
• Digby F. Warner,
• Deng Hai,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156

• presence of an oxazoline ring similar to that found in vulnibactin [27]. The key HMBC cross-peaks (Figure 2 and Supporting Information File 1) from H-9 (δH 4.46, J = 7.3 Hz, d) and H-11(δH 4.90, qd, J = 6.3, 7.3 Hz) to carboxamide C-10 (δC 175.6) and C-7 (δC 167.8), confirmed the proposed structure which

• carboxamide C-10 (δC 172.9) and the quaternary carbon C-16 (δC 140.2), between H2-15 and H-18/20 to the quaternary carbon C-16, and a strong correlation from H-15 and H-19 to C-17/20 (δC 129.9). The new oxazoline derivative 5 was named pseudomonbactin B. The absolute configuration of the threonine residue in

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• iridium(III) photocatalyst 2-I. Subsequently, Ahneman and Doyle reported a related process for the synthesis of a variety of benzylic amines 7 by the arylation of α-amino C(sp3)‒H bonds with aryl iodides 2 involving photoredox nickel catalysis (Scheme 4) [55]. In this protocol, bis(oxazoline) (BiOx) was

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• non-conductive polymers like water-soluble poly(2-ethyl-2-oxazoline) (PEtOx) [35], polypropylene (PP) [36][37] photo-cross-linkable and biodegradable poly(ʟ-lactide-co-ε-caprolactone-co-acryloyl carbonate) [38], or thermoplastic elastomers [39] have successfully been processed via MEW [40

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• control over size and substitution pattern. Classical methods include chitinase-catalyzed assembly via ring-opening polyaddition of N,N’-diacetylchitobiose oxazoline derivatives [237][238][239] or self-condensation of N-phthalimide protected thioglycoside [240]. Enzymatic polymerization promoted by

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

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

• olefins 84 as nucleophile partners and racemic secondary and tertiary α-bromo-N-protected β-lactams 83 under nickel catalysis, along with the chiral bis(oxazoline) ligand 85 and triethoxysilane (Scheme 32) [108]. Substrate structural variations on 84 had only a small impact on the reaction

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• was further demonstrated by a series of successful derivatizations of the cyano-substituted oxindole 8a. For instance, after the Ritter reaction, 8a was smoothly converted to N-tert-butylated acetamide 12 in 96% yield (Scheme 6b). A modified Witte–Seeliger reaction led to the formation of oxazoline 13

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• catalytic cycle as outlined in Scheme 21 [59]. The latest ligand derived from pyridine-oxazolines is β-carbolino-oxazoline, whose Pd(II) complex was studied mainly as a catalyst for the addition of arylboronic acids to nitrostyrenes. It also showed to be a highly active catalyst for the addition to enones

• substrates as well as for 2-unsubstituted chromones [17][18][19][21][22][23][24]. On the other hand, there is only one example of the usage of a rhodium-based catalyst for the addition of arylboronic acid to 3-substituted enones. The olefino-oxazoline ligand L18 has been used for the rhodium-catalysed

Manganese/bipyridine-catalyzed non-directed C(sp³)–H bromination using NBS and TMSN₃

• Kumar Sneh,
• Takeru Torigoe and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

• -position of an oxazoline or amide is selectively activated using a copper or palladium catalyst. Manganese is one of the most abundant and nontoxic transition metals found in the earth’s crust and its corresponding complexes and salts are useful in synthetic organic reactions [29][30][31][32][33][34][35