Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• opened by SnCl4 at −78 °C in a syn manner to give the corresponding chlorohydrins 122, which then upon treatment with BF3·OEt2 underwent the O–H insertion producing oxetanones 123 in good yields. The authors also found that increasing the temperature to rt during the epoxide opening afforded the

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

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• pentadienyl cation [1][2][3][4][5][6][7][8][9][10][11][12]. Until the past decade, the conditions used for the Nazarov reaction generally involved the use of a stoichiometric amount of a strong Lewis acid (e.g., BF3, TiCl4, SnCl4, AlCl3) in relation to the divinyl ketone derivative [21][22][23]. However

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• , t-BuOK), with Hoffer’s chlorosugar (13) in the presence or absence of Lewis acid (TMSOTf, SnCl4) did not result in formation of a reasonable amount of appropriate nucleoside (Scheme 2). Nucleobase 12 could not be converted to the corresponding silylated derivative by using HMDS, TMSCl or a

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• only 10–25% of the primary chloride for the reaction of tert-butylethylene with HCl in the presence of benzoyl peroxide [33]. c) Several metal halides such as AlCl3, SnCl4, FeCl3, and CuCl exhibit catalytic activities for the hydrochlorination of alkenes. The enthalpy of formation for the hydrogen

• chloride metal halide complexes are −6 kJ mol−1 for SnCl4, −8 kJ mol−1 for BiCl3, −9 kJ mol−1 for ZnCl2, −15 kJ mol−1 for CdCl2, −16 kJ mol−1 for FeCl3, and −41 kJ mol−1 for AlCl3. d) Addition of chloride-containing salts (e.g., LiCl) accelerate the reaction. e) Traces of water can increase the rate of the

• of HCl. No reaction was observed for terminal and 1,2-disubstituted alkenes such as cyclooctene (25) and 1-decene (53). Boudjouk and co-workers examined PCl3, SnCl4, SOCl2, SiCl4, Me2SiCl2, and Me3SiCl as hydrogen chloride sources [55]. They found that PCl3 and SnCl4 gave the desired

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

• imidated product 32. In 2018, an Fe-catalyzed carbosulfenylation and carboselenylation 33 of alkenes with N-(thio/seleno)phthalimides 14 was introduced by Lv and Li (Scheme 17) [54]. The use of Lewis acids, such as AlCl3, ZnCl2, InCl3, Fe(OTf)2 and Fe(acac)3 was not beneficial. However, BF3·OEt2, SnCl4

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• reducing agent sodium borohydride. The plausible reaction mechanism was also described for this selective N-glycosylation methodology (Scheme 40). A previously reported [72] plausible mechanism involving the use of SnCl4 was considered while proposing the mechanism when using ZrCl4 catalyst for the

• phosphonate analogue 100 (Scheme 44). To obtain both the α- and β-anomers for biological assessment, TiCl4 was used as a Lewis acid in the glycosylation procedure in place of SnCl4

Synthesis of new substituted 7,12-dihydro-6,12-methanodibenzo[c,f]azocine-5-carboxylic acids containing a tetracyclic tetrahydroisoquinoline core structure

• Agnieszka Grajewska,
• Maria Chrzanowska and
• Wiktoria Adamska

Beilstein J. Org. Chem. 2021, 17, 2511–2519, doi:10.3762/bjoc.17.168

• amino acid 6a was subjected to cyclization under different acidic conditions (not shown). The reaction of 6a with TiCl4 or SnCl4 in DCM at 0 °C led exclusively to the formation of 7a (TLC analysis) but it was impossible to isolate the product in a pure form probably due to the formation of the salts

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

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

• Rashmi Singh,
• Tomas Horsten,
• Rashmi Prakash,
• Swapan Dey and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79

• the Duff formylation procedure, only traces of aldehyde 16 were detected. Rieche formylation with either SnCl4 or TiCl4 resulted in a low conversion of the starting material and only traces of 16 due to the limited solubility of 13 in DCM, DCE, or chloroform. Furthermore, 16 was isolated after a

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• -trisubstituted tetrahydropyran 97 through Prins cyclization, as shown in Scheme 21. Similarly, an SnCl4-catalyzed Prins reaction was reported for the synthesis of 4-chlorotetrahydropyran 100. This intermediate was further utilized for the synthesis of the natural product centrolobine, as shown in Scheme 22 [56

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

• activation (e.g., SnCl4 or ZnCl2), opening an avenue for this cation to react with various nucleophiles (Scheme 51). Such a cation can also be trapped intramolecularly by a phenyl moiety; however, the length of the appended alkyl chain appeared to be of the utmost importance in this transformation. Analogous

The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization

• Sharna-kay Daley and
• Nadale Downer-Riley

Beilstein J. Org. Chem. 2020, 16, 2026–2031, doi:10.3762/bjoc.16.169

• ), was subjected to the oxidants activated carbon (Act-C), potassium ferricyanide (K3[Fe(CN)6]), p-benzoquinone and stannic chloride (SnCl4). As shown in Scheme 4, with the exception of SnCl4, all oxidants resulted in the re-oxidation of the hydroxylated substrate to naphthoquinone 7. SnCl4, however

• to be explored. The oxidants cerium(IV) ammonium nitrate (CAN), ferric chloride hexahydrate (FeCl3·6H2O), vanadium pentoxide (V2O5), PIFA, and PIDA, in addition to SnCl4, were considered. Also investigated were 2-iodoxybenzoic acid (IBX) because of its implication in single-electron oxidation [24

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• of nucleoside complex 5 (20.6 mg, 28.4 μmol) and allyltrimethylsilane (100 μL, 0.629 mmol) at 0 °C was added SnCl4 (90 μL, 1.0 M, 0.090 mmol). The solution was stirred for 1 h at 0 °C, followed by 2 h at rt. Then, NH4Cl (saturated aq, 5 drops) and NaHCO3 (saturated aq, 5 drops) were added, and a

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

• thiosialoside and halide donors. Keywords: acetolysis; acetolysis products; 2,7-anhydrosialic acid; SnCl4; Introduction Sialic acids are the most prevalent monosaccharides that are found at the nonreducing ends of glycans, and they are involved in many biologically important ligand–receptor interactions [1

• the hydroxymethyl group in 10 to furnish 11 in 82% yield. After having obtained the 2,7-anhydrosialic acid derivatives 5–11, they were subjected to various Lewis acid-catalyzed ring-opening reactions. In line with this, Sc(OTf)3-, copper(II) triflate-, and SnCl4-catalyzed acetolysis of diacetylamino

• compound 12. Due to the absence of a hydrogen bond, azido-protected glycal 13 could be used as acceptor for reactions at its OH-4 and OH-8 group [36][37]. Moreover, it was used as sialyl donor in α-selective glycosylation reactions [35]. Next, acetolysis of 2,7-anhydro derivative 6 was examined with SnCl4

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

• by BF3·OEt2-promoted glycosylation [18] with a short reaction time, exploiting anchimeric assistance, followed by Zemplén de-O-acylation. On the other hand, for the synthesis of the α-anomer 8, a SnCl4-promoted glycosylation was found to be very effective [19], but with a longer reaction time in

• acceptors and donors. Model Galp 3,4-diol acceptors and data obtained with B3LYP. Synthesis of glycosyl acceptors 1α/β and 2α/β. a) BzCl, pyridine, 0 °C, 2 h; b) BF3·OEt2, MeOH, CH2Cl2, 4 h; c) SnCl4, MeOH, CH2Cl2, 20 h; d) NaOMe/MeOH, CH2Cl2, 0 ºC, 2 h; e) (CH3)2C(OCH3)2, p-TsOH, acetone, rt, 16 h; f) 50

Acid-catalyzed rearrangements in arenes: interconversions in the quaterphenyl series

• Sarah L. Skraba-Joiner,
• Carter J. Holt and
• Richard P. Johnson

Beilstein J. Org. Chem. 2019, 15, 2655–2663, doi:10.3762/bjoc.15.258

• rearrangements had been described previously. Isomerization of o,o’-quaterphenyl (17) with SnCl4/AlCl3 catalysis has been reported to yield a mixture of p,p’- (12), m,p’- (13), and m,m’-quaterphenyl (14) [34]. p,p’-Quaterphenyl (12) and m,m’-quaterphenyl (14) were available commercially. To complete the series

Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

• Kenta Tanaka,
• Yuta Tanaka,
• Mami Kishimoto,
• Yujiro Hoshino and
• Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

• presence of a Lewis acid such as SnCl4 and AlCl3 [12][13][14]. While these reactions were proven to be useful, they require the use of stoichiometric amounts of metals and/or toxic metal reagents. Moreover, there are only a few methods for the synthesis of thioxanthylium salts despite their useful active

A review of the total syntheses of triptolide

• Xiang Zhang,
• Zaozao Xiao and
• Hongtao Xu

Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194

• key cyclization precursor ketoester 15, which was cyclized in the presence of SnCl4 to give tricyclic intermediate 83, followed by steps of functional group modification to install the butenolide (D-ring), and to finish the racemic synthesis of the key intermediate triptophenolide methyl ether (8) in

Synthesis of polydicyclopentadiene using the Cp₂TiCl₂/Et₂AlCl catalytic system and thin-layer oxidation of the polymer in air

• Zhargolma B. Bazarova,
• Ludmila S. Soroka,
• Alex A. Lyapkov,
• Мekhman S. Yusubov and
• Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

• cationic polymerization, are characterized by certain disadvantages. They have a low molecular weight, a fairly rigid structure of the polymer chains due to crosslinking processes occurring during polymerization. In addition, DCPD polymers obtained from "hard" catalytic systems, such as TiCl4, SnCl4, etc

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• pentaacetyl glucose (1) with trimethylsilyl azide in the presence of SnCl4 directly into azide 8 (Scheme 5) as was previously described for the classical batch preparation [39]. At a resident time of 7 minutes an 80% yield of azide 8 could be achieved. Conclusion In conclusion, we have demonstrated that low

Hypervalent iodine-mediated Ritter-type amidation of terminal alkenes: The synthesis of isoxazoline and pyrazoline cores

• Sang Won Park,
• Soong-Hyun Kim,
• Jaeyoung Song,
• Ga Young Park,
• Darong Kim,
• Tae-Gyu Nam and
• Ki Bum Hong

Beilstein J. Org. Chem. 2018, 14, 1028–1033, doi:10.3762/bjoc.14.89

• -iodoxybenzoic acid) and DMP (Dess–Martin periodinane) (Table 1, entries 7 and 8) gave similar yields to the background reaction. Lastly, a Lewis acid screen (Table 1, entries 9–12) was performed. Among the tested Lewis acids, AlCl3, SnCl4, TiCl4, TMSOTf and BF3·Et2O, the latter was found to be the best choice

AuBr₃-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars

• Jayashree Rajput,
• Srinivas Hotha and
• Madhuri Vangala

Beilstein J. Org. Chem. 2018, 14, 682–687, doi:10.3762/bjoc.14.56

• ][44][45]. More commonly, glycosyl azides are synthesized from per-O-acetylated sugars using trimethylsilyl azide in the presence of a variety of Lewis acids such as SnCl4 [46], TiCl4 [47][48], BF3·OEt2 [49], TMSOTf [50][51], etc. However, at higher concentration Lewis acids can potentially lead to

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• enzymes has therefore become an area of significant interest over the past 15 years [35][36]. The synthesis of N-glycan oxazolines Formation of glycosyl oxazolines Glycosyl oxazolines of monosaccharides can be produced straightforwardly using strong Lewis acids (e.g., FeCl3, SnCl4, or TMSOTf) and a fully

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• , where R = H, 7-MeO or 8-MeO [47]. a) H2NNH2 followed by H2O2, 20 h, 100 °C, 60–98%; b) PEt3, H2O, diglyme, then Na2CO3 and 5-bromouracil, rt to 120 °C, 2 h, 24–86%; c) HCl, butanol, 120 °C, 24–72 h, 27–86%; d) BSA (bis(trimethylsilyl)acetamide), Hoeffer´s α-chloro sugar, SnCl4, 0 °C to rt, 2 h, 12–41