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Journal articles on the topic 'Cyclisation'

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Author: Grafiati

Published: 4 June 2021

Last updated: 25 May 2024

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1

McBurney, Roy T., and John C. Walton. "Interplay of ortho- with spiro-cyclisation during iminyl radical closures onto arenes and heteroarenes." Beilstein Journal of Organic Chemistry 9 (June 4, 2013): 1083–92. http://dx.doi.org/10.3762/bjoc.9.120.

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Sensitised photolyses of ethoxycarbonyl oximes of aromatic and heteroaromatic ketones yielded iminyl radicals, which were characterised by EPR spectroscopy. Iminyls with suitably placed arene or heteroarene acceptors underwent cyclisations yielding phenanthridine-type products from ortho-additions. For benzofuran and benzothiophene acceptors, spiro-cyclisation predominated at low temperatures, but thermodynamic control ensured ortho-products, benzofuro- or benzothieno-isoquinolines, formed at higher temperatures. Estimates by steady-state kinetic EPR established that iminyl radical cyclisations onto aromatics took place about an order of magnitude more slowly than prototypical C-centred radicals. The cyclisation energetics were investigated by DFT computations, which gave insights into factors influencing the two cyclisation modes.

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2

Rodger, Robert T., Marlowe S. Graham, and Christopher S. P. McErlean. "Hyperconjomer stereocontrol of cationic polyene cyclisations." Organic & Biomolecular Chemistry 17, no. 37 (2019): 8551–60. http://dx.doi.org/10.1039/c9ob01364d.

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The stereochemical outcome of cationic polyene cyclisations of geranylbenzene derivatives is affected by the different reactivity of hyperconjomer intermediates. The synthesis of (±)-taiwaniaquinone G by a cationic polyene cyclisation is described.

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3

Braddock, D. Christopher, and John M. Brown. "Catalytic and Stoichiometric Lewis Acid Participation in Aldehyde Ene Cyclisations." Collection of Czechoslovak Chemical Communications 65, no. 5 (2000): 741–56. http://dx.doi.org/10.1135/cccc20000741.

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Racemic 2-isopropyl-2-methylhex-5-enal has been synthesised in order to probe ene cyclisations leading to menthol analogues. The objective was first to discover catalytic conditions for preferential cyclisation to the menthol rather than the neomenthol series and then to develop (dynamic) kinetic resolution procedures which afforded a single enantiomer of product. It was found that catalytic quantities of both Me2AlCl and a bulky methylaluminium bis(phenoxide) reagent gave products attributed to a Meerwein-Pondorff-Verley reaction. In this the aldehyde is reduced to a primary alcohol and the ene product oxidised to the corresponding α,β-unsaturated ketone. By contrast, a related bulky chloroaluminium reagent catalysed the ene cyclisation cleanly, but preferentially to the undesired neomenthyl stereoisomer.

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4

Parsons, Philip, Lewis Allen, Daniel Jones, Alex Padgham, James Pryke, Joseph McKenna, and Daniel O’Reilly. "Approaches to the Synthesis of Highly Substituted Aromatic and Fused Rings: Metal-Catalysed versus Thermal Cyclisation." Synthesis 50, no. 01 (November 27, 2017): 84–101. http://dx.doi.org/10.1055/s-0036-1590952.

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A domino reaction has been used for the construction of lactonamycin derivatives. This research led to a comparison study between palladium-mediated cascade cyclisations and thermal alkyne [2+2+2] cyclisations. A palladium-mediated cyclisation of alkenyl bromides with alkynes and furans has been shown to furnish highly substituted aromatic rings. Penta- and hexasubstituted aromatic rings have also been prepared by the thermolysis of suitably substituted alkynes under microwave conditions. Tetrasubstituted pyridines can also be prepared using nitriles instead of alkynes. This work will provide a new and interesting array of drug templates; mechanistic details are discussed for both reaction series.

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5

Taherali, Farhan, Nerisha Chouhan, Fanjin Wang, Sebastien Lavielle, Maryana Baran, Laura E. McCoubrey, Abdul W. Basit, and Vipul Yadav. "Impact of Peptide Structure on Colonic Stability and Tissue Permeability." Pharmaceutics 15, no. 7 (July 15, 2023): 1956. http://dx.doi.org/10.3390/pharmaceutics15071956.

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Most marketed peptide drugs are administered parenterally due to their inherent gastrointestinal (GI) instability and poor permeability across the GI epithelium. Several molecular design techniques, such as cyclisation and D-amino acid (D-AA) substitution, have been proposed to improve oral peptide drug bioavailability. However, very few of these techniques have been translated to the clinic. In addition, little is known about how synthetic peptide design may improve stability and permeability in the colon, a key site for the treatment of inflammatory bowel disease and colorectal cancer. In this study, we investigated the impact of various cyclisation modifications and D-AA substitutions on the enzymatic stability and colonic tissue permeability of native oxytocin and 11 oxytocin-based peptides. Results showed that the disulfide bond cyclisation present in native oxytocin provided an improved stability in a human colon model compared to a linear oxytocin derivative. Chloroacetyl cyclisation increased native oxytocin stability in the colonic model at 1.5 h by 30.0%, whereas thioether and N-terminal acetylated cyclisations offered no additional protection at 1.5 h. The site and number of D-AA substitutions were found to be critical for stability, with three D-AAs at Tyr, Ile and Leu, improving native oxytocin stability at 1.5 h in both linear and cyclic structures by 58.2% and 79.1%, respectively. Substitution of three D-AAs into native cyclic oxytocin significantly increased peptide permeability across rat colonic tissue; this may be because D-AA substitution favourably altered the peptide’s secondary structure. This study is the first to show how the strategic design of peptide therapeutics could enable their delivery to the colon via the oral route.

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6

Holst, Pia Bachmann, Uffe Anthoni, Carsten Christophersen, Sine Larsen, Per Halfdan Nielsen, Ask Püschl, Kurt V. Mikkelsen, and Alexander Senning. "Cyclisations of Tryptophans. IV. Cyclisation of Nb-Acyl-L-Tryptophanamides." Acta Chemica Scandinavica 52 (1998): 683–93. http://dx.doi.org/10.3891/acta.chem.scand.52-0683.

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7

Joyce, Liam M., Anthony C. Willis, Christopher J. T. Hyland, and Stephen G. Pyne. "Gold- and Silver-Catalysed Cyclisation Reactions of β-Amino Allenes." Australian Journal of Chemistry 71, no. 9 (2018): 682. http://dx.doi.org/10.1071/ch18197.

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Herein we report the formation of pyrrolines and tetrahydropyridines from the cyclisation reactions of β-amino allenes by both AuI and AgI catalysts in yields ranging from 5 to 70 %. AuI catalysts favour a 5-endo-dig cyclisation before rapid rearrangement to the 5-exo-dig product, while AgI favours a 6-endo-trig cyclisation. We also report the first known Ag2O catalysed cyclisation reaction of an allene which occurred in good yield (61 %).

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8

Palík, Miroslav, Jozef Kožíšek, Peter Koóš, and Tibor Gracza. "Palladium-catalysed cyclisation of alkenols: Synthesis of oxaheterocycles as core intermediates of natural compounds." Beilstein Journal of Organic Chemistry 10 (September 3, 2014): 2077–86. http://dx.doi.org/10.3762/bjoc.10.216.

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The study of Pd-catalysed cyclisation reactions of alkenols using different catalytic systems is reported. These transformations affect the stereoselective construction of mono- and/or bicyclic oxaheterocyclic derivatives depending on a starting alkenol. The substrate scope and proposed mechanism of Pd-catalysed cyclisation reactions are also discussed. Moreover, the diastereoselective Pd-catalysed cyclisation of appropriate alkenols to tetrahydrofurans and subsequent cyclisation provided properly substituted 2,5-dioxabicyclo[2.2.1]heptane and 2,6-dioxabicyclo[3.2.1]octane, respectively. Such bicyclic ring subunits are found in many natural products including ocellenynes and aurovertines.

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9

Ferguson, Jayne L., Marie A. Squire, and Christopher M. Fitchett. "Photochemical and oxidative cyclisation of tetraphenylpyrroles." Organic & Biomolecular Chemistry 15, no. 44 (2017): 9293–96. http://dx.doi.org/10.1039/c7ob02537h.

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The cyclisation of tetraphenylpyrroles under complementary conditions allows controlled cyclisation giving products dependent on N-substitution, with both tandem rearrangement and halogenation being observed.

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10

Hayes, Heather C., Louis Y. P. Luk, and Yu-Hsuan Tsai. "Approaches for peptide and protein cyclisation." Organic & Biomolecular Chemistry 19, no. 18 (2021): 3983–4001. http://dx.doi.org/10.1039/d1ob00411e.

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Polypeptide cyclisation can enhance thermal stability, proteolytic resistance and membrane permeability. Cyclisation can be achieved by methods including chemical, enzyme and protein tag approaches. Each has strengths and limitations.

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11

Morris, J. C., and C. S. P. McErlean. "Synthesis of highly enantio-enriched stereoisomers of hydroxy-GR24." Organic & Biomolecular Chemistry 14, no. 4 (2016): 1236–38. http://dx.doi.org/10.1039/c5ob02349a.

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12

Truman, Andrew W. "Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides." Beilstein Journal of Organic Chemistry 12 (June 20, 2016): 1250–68. http://dx.doi.org/10.3762/bjoc.12.120.

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Ribosomally synthesised and post-translationally modified peptides (RiPPs) are a large class of natural products that are remarkably chemically diverse given an intrinsic requirement to be assembled from proteinogenic amino acids. The vast chemical space occupied by RiPPs means that they possess a wide variety of biological activities, and the class includes antibiotics, co-factors, signalling molecules, anticancer and anti-HIV compounds, and toxins. A considerable amount of RiPP chemical diversity is generated from cyclisation reactions, and the current mechanistic understanding of these reactions will be discussed here. These cyclisations involve a diverse array of chemical reactions, including 1,4-nucleophilic additions, [4 + 2] cycloadditions, ATP-dependent heterocyclisation to form thiazolines or oxazolines, and radical-mediated reactions between unactivated carbons. Future prospects for RiPP pathway discovery and characterisation will also be highlighted.

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13

Belyaeva, Natalya P. "LITERARY WAYS OF CYCLISATION IN MODERN ROCK POETRY (based on the album “Creativity in the Void” by the “DDT”)." Vestnik of Kostroma State University 29, no. 3 (December 21, 2023): 159–65. http://dx.doi.org/10.34216/1998-0817-2023-29-3-159-165.

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This article is intended to concretise the methods of cyclisation in the album “Creativity in the Voidˮ of the “DDTˮ, the presence of which indicates the integrity of the musical collection of it. The real goal dictates the solution of several research tasks, including the theoretical substantiation of cyclisation as a scientific problem in the study of rock poetry, the identification of the characteristic features of cyclisation inherent in the poetry of rock performers, and the analysis of the logic of building the album “Creativity in the Voidˮ of the rock band “DDT”. When performing the work, analytical methods of research, synthesis and comparison were applied, sociocultural and some biographical factors were considered, which makes it possible to reveal the philosophical and aesthetic meanings inherent in the single artistic space of the collection as a “product” of cyclisation. The author of this article concludes that the phenomenon of cyclisation is inherent in the work of the rock band “DDT”. The non-randomness of the arrangement of texts in the structure of the album has an impact on the interpretation of the picture of the world of the poet Yuri Shevchuk, which is artistically explicated in the musical works included in the framework of a separate album. The conclusions of the study make a certain contribution to the development of ideas about the artistic originality of the named musical band, expand the understanding of the phenomenon of cyclisation, including metacyclisation, in the work of rock performers in general.

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14

Omori, Hiroto, Satoru Hiroto, and Hiroshi Shinokubo. "The synthesis of NiII and AlIII 10-azacorroles through coordination-induced cyclisation involving 1,2-migration." Chemical Communications 52, no. 17 (2016): 3540–43. http://dx.doi.org/10.1039/c5cc10247b.

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We have synthesized Ni^II and Al^III 10-azacorroles through coordination-induced cyclisation of nitrogen-bridged bisdipyrrins. The α-substituent (X = Br or Ph) shifted to the adjacent β-position during cyclisation.

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15

Tufail, Afzaal, Saeed Akkad, Natasha E. Hatton, Nicholas D. J. Yates, Richard J. Spears, Tessa Keenan, Alison Parkin, Nathalie Signoret, and Martin A. Fascione. "Cross aldol OPAL bioconjugation outcompetes intramolecular hemiaminal cyclisation of proline adjacent N-terminal α-oxo aldehydes at acidic pH." RSC Advances 14, no. 6 (2024): 3723–29. http://dx.doi.org/10.1039/d3ra08776j.

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Bioconjugation at N-terminal α-oxo aldehydes is challenging when proline is adjacent due to competing cyclisation. In this study we show aldol bioconjugations can outcompete this cyclisation at acidic pH in modifications of peptides and proteins.

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16

Shepherd, Nicholas D., Harrison S. Moore, Jonathon E. Beves, and Deanna M. D’Alessandro. "Electrochemical Switching of First-Generation Donor-Acceptor Stenhouse Adducts (DASAs): An Alternative Stimulus for Triene Cyclisation." Chemistry 3, no. 3 (July 7, 2021): 728–33. http://dx.doi.org/10.3390/chemistry3030051.

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Donor-acceptor Stenhouse adducts (DASAs) are a photo-switch class that undergoes triene cyclisation in response to visible light. Herein, electrochemical oxidation is demonstrated as an effective alternative stimulus for the triene cyclisation commonly associated with photo-switching.

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17

Klein, Michael, Thomas Walenzyk, and Burkhard König. "Electronic Effects on the Bergman Cyclisation of Enediynes. A Review." Collection of Czechoslovak Chemical Communications 69, no. 5 (2004): 945–65. http://dx.doi.org/10.1135/cccc20040945.

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The thermal cyclisation of enediynes to benzene-1,4-diyl diradicals (Bergman cyclisation) is affected by geometrical and electronic conditions. While the effect of ring strain or conformational constrains on the cyclisation temperature has been investigated in detail, electronic contributions have been less studied. Often geometrical and electronic contributions cannot be clearly distinguished. In most cases metal ion chelation does involve both. In this review we have summarised clear-cut observations of electronic substituents effects on the thermal enediyne reactivity. The effects of substituents in the vinylic and terminal alkyne position, the influence of benzo-fusion and hetarene fusion, as well as the changes induced by heteroatoms in the enediyne skeleton, are within the scope of this review. With the exception of more complex heterocyclic hetarene-fused enediynes the experimental data of electronic substituent effects on the thermal Bergman cyclisation of enediynes follow theoretical predictions. A review with 57 references.

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18

Srikrishna, A., and K. C. Pullaiah. "Furannulation radical cyclisation." Tetrahedron Letters 28, no. 43 (1987): 5203–4. http://dx.doi.org/10.1016/s0040-4039(00)95629-6.

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19

Cremlyn, Richard J., Frederick J. Swinbourne, Olufemi O. Shode, and John Lynch. "Cyclisation of benzils." Journal of Heterocyclic Chemistry 24, no. 1 (January 1987): 117–21. http://dx.doi.org/10.1002/jhet.5570240124.

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20

Holzapfel, Cedric W., Gerhard J. Engelbrecht, Lizel Marais, and Francois Toerien. "Stereocontrolled palladium(0) catalysed cyclisation and cyclisation/carbonylation of pseudoglycal derivatives." Tetrahedron 53, no. 11 (March 1997): 3957–74. http://dx.doi.org/10.1016/s0040-4020(97)00012-4.

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21

Khattab, Ahmed F., and Farag A. El-Essawy. "Formation of Novel Pyrido[3′,2′:4,5]Thieno [2,3-e][1,2,4]Triazolo[4,3-c] Pyrimidines and their Acyclic C-Nucleosides Analogues: Synthesis of 3-(Alditol-1-yl)Pyridothienotriazolopyrimidines." Journal of Chemical Research 2005, no. 11 (November 2005): 736–40. http://dx.doi.org/10.3184/030823405774909298.

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A series of the hydrazones were prepared by the reaction of 4-hydrazino-7,9-dimethylpyrido[3′,2′:4,5]thieno [2,3-d]pyrimidine (1) with monosaccharides, and their acetylation was studied. The oxidative cyclisation of the hydrazones 3a–c gave 3-(Alditol-1-yl)-pyridothienotriazolopyrimidenes 5a–c, whose acetylation was carried out. Also, oxidative cyclisation of arylidenes 7a,b gave the pyridothienotriazolopyrimidines 8a,b.

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22

Ashry, El Sayed H. El, Shaker Youssif, Maged El Ahwany, and Mohamed El Sanan. "Synthesis of 3-benzylxanthine and Lumazine Analogues." Journal of Chemical Research 2005, no. 4 (April 2005): 262–66. http://dx.doi.org/10.3184/0308234054213438.

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Several xanthines (7–13) are prepared by the cyclisation of 1-benzyl-5,6-diaminouracil with single-carbon inserting agents such as aromatic aldehydes, formamides, acetic anhydride, carbon disulfide, and nitrous acid. Treatment of 6-amino-1-benzyl-5-nitrosouracil with anilinobenzylidene derivatives (14–18) affords 7-hydroxyxanthines (19–23). Cyclisation of the diaminouracil 3 with glyoxal, benzil, and diethyl oxalate leads to lumazines (25–28).

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23

Wróblewski, Andrzej E. "Synthesis of Substituted 3-(β,β-Dimethylhydrazino)- 2-methoxy-2-oxo-1,2-oxaphospholanes+." Zeitschrift für Naturforschung B 40, no. 3 (March 1, 1985): 407–15. http://dx.doi.org/10.1515/znb-1985-0317.

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Cyclisation of δ-(N,N-dimethylhydrazono)alkyl phosphites afforded the title compounds in moderate to high yields. The ring closure was highly diastereoselective leading to an excess of the diastereomers with the β,β-dimethylhydrazino and MeOP groups in the trans configuration. The structure and relative configurations of diastereomeric pairs were established by 1H and 13C NMR spectroscopy. A mechanism of cyclisation was proposed.

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24

Cahyono, Edy, Muchalal Muchalal, Triyono Triyono, and Harno Dwi Pranowo. "CYCLISATION-ACETYLATION KINETIC OF (R)-(+)-CITRONELLAL BY Zn²⁺–NATURAL ZEOLITE AS SOLID SOLVENT CATALYST." Indonesian Journal of Chemistry 10, no. 2 (July 21, 2010): 189–94. http://dx.doi.org/10.22146/ijc.21459.

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Kinetic in cyclisation-acetylation of (R)-(+)-citronellal with acetic anhydride was investigated over Zn2+-Natural zeolite (Zn2+-Natzeo) as a catalyst. (R)-(+)-citronellal has been isolated from citronella oil by fractional distillation under reducing pressure. Enantioselective capillary GC on a Supelco β-DEX 225 column has been used for analysis the enantiomers ratio of citronellal. Catalyst Zn2+-Natzeo has prepared through acid activation of natural zeolite from Malang using HF 1% and HCl 6 M, followed by ion-exchange with 3 M NH4Cl and calcination at 450 °C for 1 h under nitrogen to obtained H-natural zeolite (H-Natzeo). H-Natzeo was modified to Zn2+-Natzeo by ion exchange with 0.1 M ZnCl2. Cyclisation-acetylation reaction was carried out by heating (R)-(+)-citronellal (CIT), acetic anhydride (AA), and 1 g catalyst in glass batch reactor with vigorous stirring at 80 °C. Molar ratio CIT/AA that used, i.e. 0.25; 0.5; 1.0; 1.2 and 1.5. As the reaction proceeded, 1 mL sample was taken off at 10; 20; 30; 60; 120; 180 min and extracted using n-hexane for every molar ratio. Structure analysis of product was conducted by GC-MS. Kinetic of the cyclisation-acetylation reaction was analyzed according to the Langmuir-Hinshelwood mechanism. Increasing molar ratio of CIT/AA will decrease the isopulegyl acetate (IPA) and neo-isopulegyl acetate (NIPA) formation. Rate constant of cyclisation-acetylation reaction catalyzed by Zn2+-Natzeo was 30.964-47.619 mmol(min. g cat)-1 at 80 °C, 30 min and the ratio adsorption equilibrium constant KCIT/KAA was 7.09. Keywords: Cyclisation-acetylation, (R)-(+)-citronellal, Zn2+-natural zeolite, kinetic

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25

Majumdar, K. C., P. Chatterjee, and A. K. Kundu. "Cyclisation ofOrtho-Cyclohexenyl PhenolsviaEpoxidation#." Synthetic Communications 26, no. 17 (September 1996): 3331–44. http://dx.doi.org/10.1080/00397919608004643.

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26

Dean, Christopher, and David Whittaker. "Citronellal cyclisation in superacids." Journal of the Chemical Society, Perkin Transactions 2, no. 7 (1990): 1275. http://dx.doi.org/10.1039/p29900001275.

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27

Zheng, Zhitong, Zhixun Wang, Youliang Wang, and Liming Zhang. "Au-Catalysed oxidative cyclisation." Chemical Society Reviews 45, no. 16 (2016): 4448–58. http://dx.doi.org/10.1039/c5cs00887e.

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28

Thebtaranonth, C., and Y. Thebtaranonth. "Developments in cyclisation reactions." Tetrahedron 46, no. 5 (January 1990): 1385–489. http://dx.doi.org/10.1016/s0040-4020(01)81956-6.

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29

Tsankova, Elena, and Valentin Enev. "Oxidative cyclisation of germacrone." Tetrahedron 43, no. 19 (January 1987): 4425–32. http://dx.doi.org/10.1016/s0040-4020(01)90318-7.

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30

Ruchkina, Elena L., Alexander J. Blake, and Mark Mascal. "The vinylogous Witkop cyclisation." Tetrahedron Letters 40, no. 48 (November 1999): 8443–45. http://dx.doi.org/10.1016/s0040-4039(99)01760-8.

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31

Bowman, W. Russell, Colin F. Bridge, and Philip Brookes. "Radical cyclisation onto nitriles." Tetrahedron Letters 41, no. 46 (November 2000): 8989–94. http://dx.doi.org/10.1016/s0040-4039(00)01596-3.

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32

Niddam, Valérie, Martial Medou, Jean Dessolin, Carole Trabaud, Michel Camplo, and Jean-Louis Kraus. "Urea cyclisation reaction studies." Journal of Heterocyclic Chemistry 34, no. 3 (May 1997): 829–33. http://dx.doi.org/10.1002/jhet.5570340320.

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33

Brown, Alan, Ronald Grigg, Thangavelauthum Ravishankar, and Mark Thornton-Pett. "Palladium catalysed cyclisation-cyclopropanation and cyclisation - anion capture processes of vinyl triflates." Tetrahedron Letters 35, no. 17 (April 1994): 2753–56. http://dx.doi.org/10.1016/s0040-4039(00)77024-9.

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34

Rinkel, Jan, Patrick Rabe, Laura zur Horst, and Jeroen S. Dickschat. "A detailed view on 1,8-cineol biosynthesis by Streptomyces clavuligerus." Beilstein Journal of Organic Chemistry 12 (November 4, 2016): 2317–24. http://dx.doi.org/10.3762/bjoc.12.225.

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The stereochemical course of the cyclisation reaction catalysed by the bacterial 1,8-cineol synthase from Streptomyces clavuligerus was investigated using stereospecifically deuterated substrates. In contrast to the well investigated plant enzyme from Salvia officinalis, the reaction proceeds via (S)-linalyl diphosphate and the (S)-terpinyl cation, while the final cyclisation reaction is in both cases a syn addition, as could be shown by incubation of (2-13C)geranyl diphosphate in deuterium oxide.

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35

Li, Yang, Ming-qin Chang, Feng Gao, and Wen-tao Gao. "Facile synthesis of fused quinolines via intramolecular Friedel–Crafts acylation." Journal of Chemical Research 2008, no. 11 (November 2008): 640–41. http://dx.doi.org/10.3184/030823408x375070.

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The intramolecular cyclisation of 6-[(phenoxy/phenylthio)methyl][1,3]dioxolo[4,5-g]quinoline-7-carboxylic acids to [1]benzoxepino[3,4-b][1,3]dioxolo[4,5-g]quinolin-12(6H)-onesand[1]benzothiepino[3,4-b][1,3]dioxolo[4,5-g]quinolin-12(6H)-ones in the presence of Eaton's reagent (P2O5-MeSO3H) is described. This cyclisation protocol requires milder conditions than those traditionally employed and is characterised by relatively low reaction temperatures and ease of product isolation.

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36

Davies, Jacob, and Daniele Leonori. "The first calcium-catalysed Nazarov cyclisation." Chem. Commun. 50, no. 96 (2014): 15171–74. http://dx.doi.org/10.1039/c4cc06501h.

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37

Biswas, Titas Biswas, and Swapan Kumar Biswas. "Utility of iodine catalyzed tandem oxidation, cross-coupling and cyclisation reactions in organic synthesis." International Journal of Experimental Research and Review 27 (April 30, 2022): 39–44. http://dx.doi.org/10.52756/ijerr.2022.v27.004.

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Molecular iodine is an eco-friendly, powerful catalyst and plays an important role in pharmaceutical, medicinal and organic chemistry. For a long time, molecular iodine has been hugely applied in carbohydrate chemistry. Due to the huge application of molecular iodine in oxidation, cross coupling and cyclisation reactions, it has emerged as an elegant tool in organic synthesis. Earlier I discussed (Biswas, 2021) on iodine mediated cascade oxidative functionalisation, cyclisation and annulation reactions. In this review, I describe the utility of iodine catalysed tandem oxidation, cross coupling, and cyclisation reactions in organic synthesis. Molecular iodine catalysed mild oxidative conditions yielding desired products, and oxidising techniques applied to the efficient synthesis tolerate a wide range of starting materials with aryl or alkyl replacements. These reactions were carried out as a one-pot or multi-step eco-friendly process that could be used for a wide range of drug and pharmaceutical product synthesis.

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38

Anthoni, Uffe, Carsten Christophersen, Per Halfdan Nielsen, Martin W. Christoffersen, Dan Sørensen, Kerstin Nordström, and Christina Moberg. "Cyclisations of Tryptophans. VI. Cyclisation of L-Tryptophan Dipeptides by Oxygenation with Singlet Oxygen." Acta Chemica Scandinavica 52 (1998): 958–60. http://dx.doi.org/10.3891/acta.chem.scand.52-0958.

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39

Ren, Hexiang, Yuanyang Mu, Ming Zhang, and Ai Qin Zhang. "Synthesis of 3-Phenylsulfonylcoumarins by Cyclisation of Phenyl Propiolates with Sulfinic Acids or Sodium Sulfinates." Journal of Chemical Research 42, no. 10 (October 2018): 515–20. http://dx.doi.org/10.3184/174751918x15385227785338.

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Methods for the synthesis of 3-phenylsulfonylcoumarins by radical sulfonylation cyclisation of phenyl propiolates with sulfinic acids or sodium sulfinates as sulfonyl sources have been developed. A combination of potassium persulfate as oxidant and silver nitrate as catalyst, or tert-butyl hydroperoxide as oxidant and potassium iodide as catalyst were used. The products were formed by an ipso-cyclisation/1,2-ester migration mechanism. The toleration of functional groups is broad and the yield is up to 96%.

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40

Brown, Dearg, Ronald Grigg, Visuvanathar Sridharan, Vasuki Tambyrajah, and Mark Thornton-Pett. "Palladium catalysed cyclisation- intermolecular cyclopropanation versus cyclisation Friedel- Crafts alkylation with olefin insertion." Tetrahedron 54, no. 11 (March 1998): 2595–606. http://dx.doi.org/10.1016/s0040-4020(98)00022-2.

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41

Loizzi, Marianna, David J. Miller, and Rudolf K. Allemann. "Silent catalytic promiscuity in the high-fidelity terpene cyclase δ-cadinene synthase." Organic & Biomolecular Chemistry 17, no. 5 (2019): 1206–14. http://dx.doi.org/10.1039/c8ob02821d.

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42

Aimon, Anthony, Louis J. Farrugia, and J. Stephen Clark. "Synthesis of the Core Framework of the Cornexistins by Intramolecular Nozaki-Hiyama-Kishi Coupling." Molecules 24, no. 14 (July 22, 2019): 2654. http://dx.doi.org/10.3390/molecules24142654.

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A new and direct approach to the construction of the core framework of the herbicidal natural products cornexistin and hydroxycornexistin has been developed. Formation of the nine-membered carbocycle found in the natural products has been accomplished by an intramolecular Nozaki-Hiyama-Kishi reaction between a vinylic iodide and an aldehyde. Good yields of carbocyclic products were obtained from the reaction, but diastereomeric mixtures of allylic alcohols were produced. The cyclisation reaction was successful irrespective of the relative configuration of the stereogenic centres in the cyclisation precursor.

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Grigg, Ronald, William S. MacLachlan, David T. MacPherson, Visuvanathar Sridharan, and Selvaratnam Suganthan. "Palladium catalysed tandem cyclisation–anion capture. Part 8: Cascade hydrostannylation—cyclisation–anion capture and cascade hydroboration—cyclisation–anion capture on solid phase." Tetrahedron 57, no. 52 (December 2001): 10335–45. http://dx.doi.org/10.1016/s0040-4020(01)01061-4.

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44

Jana, Saibal, and Anakuthil Anoop. "Effect of π–π interaction in Bergman cyclisation." Physical Chemistry Chemical Physics 17, no. 44 (2015): 29793–802. http://dx.doi.org/10.1039/c5cp05395a.

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45

Fairley, Michael, Laia Davin, Alberto Hernán-Gómez, Joaquín García-Álvarez, Charles T. O'Hara, and Eva Hevia. "s-Block cooperative catalysis: alkali metal magnesiate-catalysed cyclisation of alkynols." Chemical Science 10, no. 22 (2019): 5821–31. http://dx.doi.org/10.1039/c9sc01598a.

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46

Shah, Abdul Karim, Ghulam Abbas Kandhro, Aqeel Ahmed Shah, Syed Nizam Uddin Shah Bukhari, Arshad Iqbal, Muhammad Azam Usto, Taswar Hussain Laghari, and Sohail Ahmed. "Synthesis of Isopulegol Through Cyclisation of Citronellal Using Solid Acid Catalysts: Catalytic Reaction Performance Evaluation and Process Parameters Optimization." Pakistan Journal of Analytical & Environmental Chemistry 22, no. 2 (December 23, 2021): 252–63. http://dx.doi.org/10.21743/pjaec/2021.12.04.

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The cyclisation of citronellal to isopulegol is a significant intermediate stage in the production of menthols. In this research work, the effects of acid treatment on montmorillonite clay have been investigated and used in citronellal cyclisation reactions. Furthermore, the effects of acid treatment and hetero-poly acid impregnation have been determined on the textural and catalytic properties of montmorillonite clay. The designed catalysts were characterized by XRD, N2 sorption, and NH3- TPD techniques. Acid treatment of montmorillonite resulted in the enhancement of surface area and pore volume. The catalytic activity and selectivity parameters were lessened due to the severe leaching of Al ions from tetrahedral crystalline structures (e.g., weakened structure and loss of acidity). Among all prepared materials, the heteropoly acid supported HCl treated montmorillonite catalyst was observed as a more active, stable, and selective catalyst that showed the highest catalytic performance in citronellal cyclisation under optimized process parameters. The catalytic activity and selectivity were enhanced with rising mesoporosity and acidity parameters due to HCl acid treatment and HPA impregnation.

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Davies, Stephen, Ai Fletcher, Paul Roberts, and James Thomson. "Asymmetric Synthesis of Pyrrolizidines, Indolizidines and Quinolizidines via a Double Reductive Cyclisation Protocol." Synlett 28, no. 20 (August 8, 2017): 2697–706. http://dx.doi.org/10.1055/s-0036-1590975.

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This account describes an overview of the asymmetric syntheses of pyrrolizidines, indolizidines and quinolizidines via a common double reductive cyclisation protocol. The highly diastereoselective conjugate addition of an enantiopure lithium amide to an α,β-unsaturated ester incorporating a terminal C=C bond installed the nitrogen-bearing stereogenic centre and was followed by enolate functionalisation to introduce the second olefinic functionality. Alternatively, conjugate addition to the corresponding α-alkenyl α,β-unsaturated ester followed by α-protonation of the intermediate enolate may also be used to access the cyclisation precursor. After oxidation of the two terminal olefinic units to give the corresponding dialdehyde, tandem hydrogenolysis/hydrogenation was employed to efficiently construct the azabicyclic core of each target molecule. This double reductive cyclisation strategy was successfully utilised in the syntheses of 13 azabicyclic alkaloids or closely related analogues.1 Introduction2 Asymmetric Syntheses of (–)-Isoretronecanol and (–)-Trachelanthamidine3 Asymmetric Syntheses of (+)-Trachelanthamidine [(+)-Laburnine], (+)-Tashiromine and (+)-epi-Lupinine4 Asymmetric Syntheses of (–)-Hastanecine, (–)-Turneforcidine and (–)-Platynecine5 Asymmetric Syntheses of (–)-Macronecine, (–)-Petasinecine, (–)-1-epi-Macronecine, (+)-1-epi-Petasinecine and (+)-2-epi-Rosmarinecine6 Conclusion

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Lang, Ming, and Jian Wang. "A carbene-catalyzed tandem isomerization/cyclisation strategy: an efficient assembly of benzoxazinones." Organic Chemistry Frontiers 6, no. 9 (2019): 1367–71. http://dx.doi.org/10.1039/c9qo00094a.

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Kataoka, Tadashi, Mitsuhiro Yoshimatsu, Yoshinori Noda, Takashi Sato, Hiroshi Shimizu, and Mikio Hori. "Versatile cyclisation reactions using selenoboranes." Journal of the Chemical Society, Perkin Transactions 1, no. 1 (1993): 121. http://dx.doi.org/10.1039/p19930000121.

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Ahmad-Junan, S. Asiah, and Donald A. Whiting. "Rotenoid synthesis via radical cyclisation." Journal of the Chemical Society, Chemical Communications, no. 17 (1988): 1160. http://dx.doi.org/10.1039/c39880001160.

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