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Auteur : Grafiati
Publié le 6 septembre 2023

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1

Kassam, Karim, Paul C. Venneri et John Warkentin. « Reactions of alkoxyaryloxycarbenes with tethered triple bonds : a new synthesis of substituted benzofurans ». Canadian Journal of Chemistry 75, no 9 (1 septembre 1997) : 1256–63. http://dx.doi.org/10.1139/v97-152.

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Cyclic 3-alkoxy-3-aryloxyvinylcarbenes can be generated by a highly exo-selective intramolecular cyclization of a dioxycarbene onto a tethered triple bond. Like their dialkoxy counterparts, the 3-alkoxy-3-aryloxyvinylcarbene intermediates are capable of interesting reactions. In contrast to 3,3-dialkoxyvinylcarbenes, which undergo a formal [3 + 2] cycloaddition with highly electron-deficient olefins such as benzylidenemalononitrile, 3-alkoxy-3-aryloxyvinylcarbenes undergo a highly diastereoselective [1 + 2] cycloaddition with benzylidenemalononitrile to give cyclopropylketene acetals. At high temperatures, those cyclopropylketene acetals undergo a clean vinylcyclopropane rearrangement in which the stereochemical integrity of the cyclopropane is retained. Keywords: carbene, alkoxyaryloxy, [1 + 2] cycloaddition, ketene acetal, vinylcyclopropane rearrangement, oxadiazoline.
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2

Buzatu, Alina Ramona, August E. Frissen, Lambertus A. M. van den Broek, Anamaria Todea, Marilena Motoc et Carmen Gabriela Boeriu. « Chemoenzymatic Synthesis of New Aromatic Esters of Mono- and Oligosaccharides ». Processes 8, no 12 (11 décembre 2020) : 1638. http://dx.doi.org/10.3390/pr8121638.

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An efficient and convenient chemoenzymatic route for the synthesis of novel phenolic mono-, di- and oligosaccharide esters is described. Acetal derivatives of glucose, sucrose, lactose and inulin were obtained by chemical synthesis. The fully characterized pure sugar acetals were subjected to enzymatic esterification with 3-(4-hydroxyphenyl) propionic acid (HPPA) in the presence of Novozyme 435 lipase as a biocatalyst. The aromatic esters of alkyl glycosides and glucose acetal were obtained with good esterification yields, characterized by mass spectrometry (MALDI-TOF MS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR). The synthesis of aromatic esters of disaccharide acetals was successful only for the enzymatic esterification of sucrose acetal. The new chemoenzymatic route allowed the synthesis of novel aromatic esters of inulin as the inulin monoacetal monoester and diester and the inulin diacetal monoester with a polymerization degree of two, as well as the inulin monoacetal monoester with a degree of polymerization of three, were obtained by enzymatic acylation of inulin acetals with HPPA. These compounds could represent a new class of sugar ester surfactants with enhanced bioactivity, antioxidative and antimicrobial properties and with potential application in drug delivery systems.
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3

de Carvalho, Leandro Lara, Robert Alan Burrow et Vera Lúcia Patrocinio Pereira. « Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO4 ». Beilstein Journal of Organic Chemistry 9 (30 avril 2013) : 838–45. http://dx.doi.org/10.3762/bjoc.9.96.

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Chiral nonracemic aminated nitroso acetals were synthesized via diastereoselective multicomponent [4 + 2]/[3 + 2] cycloadditions employing new (S,E)-γ-nitrogenated nitroalkenes 5a–c as heterodienes, ethyl vinyl ether (EVE) as a dienophile, and selected electron-deficient alkenes as 1,3-dipolarophiles. The employment of different organic solutions of LiClO4 or LiCl as promoter systems provided the respective nitroso acetals with yields from 34–72% and good levels of diastereoselectivity. In addition, the nitroso acetal 9c was transformed to the pyrrolizidin-3-one derivative 14c, proving the usefulness of the route in the synthesis of an interesting chiral compound. The elucidation of the stereostructures was based on 2D COSY, NOESY and HSQC NMR experiments as well as an X-ray diffraction experiment.
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4

Hlavatý, Jaromír, et Miroslav Polášek. « Electrochemical Preparation of Alkynedial Tetramethyl Acetals ». Collection of Czechoslovak Chemical Communications 73, no 1 (2008) : 19–23. http://dx.doi.org/10.1135/cccc20080019.

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Tetramethyl acetals of alkynedials were prepared by anodic oxidation of corresponding alkyne-1,ω-diols (C4 and C6) in trimethyl orthoformate on glassy carbone anode in 80% yield. 1,1,4,4-Tetramethoxybut-2-yne (2a) can be prepared by this one-step procedure from but-2-yne-1,4-diol (1a) instead of a multistep chemical procedure starting from 2,5-dimethoxyfuran. Propargyl alcohol (3) can be similarly anodically oxidized in trimethyl orthoformate giving dimethyl acetal of propynal (4) in 85% yield.
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5

Collins, DJ, LM Downes et M. Kyriakou. « Enolic Ortho Esters. III. Preparation of a Keto Acetal by Hydride Reduction of an Enolic Ortho Ester ». Australian Journal of Chemistry 42, no 9 (1989) : 1617. http://dx.doi.org/10.1071/ch9891617.

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Lithium aluminium hydride reduction of the enolic ortho ester 4′,4′-dimethyl-3,4,5,8-tetra-hydrospiro [2H-l-benzopyran-2,21-[1,3]dioxolan] (8) in the absence of solvent gave 6-[21-(4″,4″- dimethyl-1″,3″-dioxolan-2″-yl)ethyl]cyclohex-3-en-1-one (11) which was isomerized to the α'β-unsaturated keto acetal (10). Similarly, hydride reduction of the phenolic ortho ester 4′-methyl-3,4-dihydrospiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (12a) and the 4′,4′-dimethyl analogue (12b), afforded the corresponding phenolic acetals (14a) and (14b) respectively, in high yields.′
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6

Pashkovsky, F. S., D. I. Korneev et F. A. Lakhvich. « Transformations of 3,7-interphenylene 11-deoxyprostanoid formyl precursors in the acidic medium ». Doklady of the National Academy of Sciences of Belarus 65, no 6 (26 décembre 2021) : 702–7. http://dx.doi.org/10.29235/1561-8323-2021-65-6-702-707.

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It has been shown that the formyl precursors of 3,7-interphenylene 11-deoxyprostanoids, formed during acidic hydrolysis of the corresponding acetals, can undergo isomerization (disproportionation) in the acidic medium to give 2-(arylalkyl)-3-(hydroxymethyl)cyclopent-2-ene-1-ones – the synthons for prostanoids and phytoprostanes of the series B. Acetal precursors of 3,7-interphenylene 11-deoxyprostaglandin analogues with electron-donating alkoxy substituent in position 3′ of the aromatic fragment in the α-chain under similar conditions hydrolyze with the formation of formyl derivatives that spontaneously cyclize to produce 2,3,4,9-tetrahydro-1H-cyclopenta[b]naphthalene-1-ones.
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7

Blanáriková-Hlobilová, Iva, Lubor Fišera, Naďa Prónayová et Marian Koman. « 1,3-Dipolar Cycloadditions of D-Erythrose- and D-Threose-Derived Alkenes with Nitrones ». Collection of Czechoslovak Chemical Communications 68, no 5 (2003) : 951–64. http://dx.doi.org/10.1135/cccc20030951.

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The new chiral terminal alkenes derived from cyclic acetals of D-erythrose 1-3 and D-threose 5, 6 were prepared. The alkenes 1, 2 and 5 react with chiral nitrones to afford the corresponding diastereomeric isoxazolidines 19-21. The stereoselectivity was dependent on the steric hindrance of the nitrone. In all cases the cycloadditions are endo-selective. The major products were found to have the C-3/C-4 erythro- and C-3/C-3a cis-configuration. Its formation can be rationalized by a less hindered endo-attack of the (Z)-nitrone in an antiperiplanar manner with respect to the largest group of the cyclic acetal.
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8

Lopez, JC, AM Gomez et B. Fraserreid. « Cyclization Reactions of Tethered Radicals Derived From 4-O-Substituted α-D-erythro-Octa-2,6-dienopyranosides : Stereoselective Access to Carbocycles and Branched-Chain Sugars ». Australian Journal of Chemistry 48, no 2 (1995) : 333. http://dx.doi.org/10.1071/ch9950333.

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The chemo- and stereo- selectivities in the cyclization of tethered radicals, derived from α-D-erythro-octa-2,6-dienopyranosides, in which there is competition between 5-exo and 6-exo ring closures, have been examined. Use of silicon tethers resulted in a preferred 6-exo-trig addition. However, tethered mixed iodo acetals have shown an unprecedented relation between the stereogenic centre in the acetal and the preferred addition pathway. In addition, changes in the oxidation state at the termini of the olefins have a profound effect upon site selectivity, thus leading to 3-deoxy 3-C-substituted carbohydrates, off-template branched-chain sugars, or functionalized cyclopentanes.
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9

Denmark, Scott E., Vito Guagnano et Jean Vaugeois. « Studies on the reduction and hydrolysis of nitroso acetals ». Canadian Journal of Chemistry 79, no 11 (1 novembre 2001) : 1606–16. http://dx.doi.org/10.1139/v01-132.

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Chemical transformation of nitroso acetals derived from tandem [4 + 2]/[3 + 2] cycloadditions of nitroalkenes have been investigated. New reduction methods were surveyed in an attempt to supplant the use of hydrogen and Raney nickel. Homogeneous catalytic hydrogenation was not successful, but samarium diiodide did effectively and selectively cleave one of the N—O bonds in a number of nitroso acetals. Acid-promoted hydrolysis of the nitroso acetals produced both α-alkoxy nitrones and hydroxamic acids selectively via expected pathways.Key words: nitroso acetals, hydroxamic acids, α-alkoxy nitrones, reduction, hydrolysis.
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10

Yakovleva, Marina P. « Low-temperature reduction of acyclic carvomentholactone derivatives with diisobutylaluminum hydride in methylene chloride ». Butlerov Communications 61, no 2 (29 février 2020) : 24–28. http://dx.doi.org/10.37952/roi-jbc-01/20-61-2-24.

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Earlier, we discovered a novel reaction in the chemistry of organoaluminum compounds - the formation of O-isobutyl acetals during low-temperature (-70 °С) treatment of a number of seven-membered lactones with a twofold (or more) molar amount of diisobutylaluminium hydride in methylene chloride. In addition, it was shown that the acyclic derivatives of (-)-mentholactone - methyl 6-hydroxy-3,7-dimethyl-octanoate and its 6-oxo analogue - also enter into the low-temperature reduction reaction of diisobutylaluminum hydride in methylene chloride. Moreover, methyl 6-hydroxy-3,7-dimethyloctanoate in this reaction behaves similarly to (-)-mentholactone: when 4 equivalents of diisobutylaluminium hydride acts on it, the reaction proceeds with the predominant formation of isobutyl acetal as the only (2S,7S)-epimer. Methyl 6-oxo-3,7-dimethyl octanoate in a low-temperature reduction reaction with 4 equivalents of diisobutylaluminium hydride in methylene chloride acts as a mixture of (-)-mentholactone and isomentolactone, leading to a mixture of (2S,7S)-, (2S,7R)- and (2R,7R)-isobutyl acetals in a ratio of 3.2: 1.3: 1.0, respectively. In the present work, when low-temperature reduction was involved in the reaction with diisobutylaluminium hydride, methyl (3R)-6-hydroxy- or (3R)-6-oxo-3-isopropylheptanoates available from carvomentolactone reacted without the formation of isobutyl acetal: a mixture of (2: 1) 6-hydroxy-(3R)-isopropylheptanal and (4R)-isopropyl-7-methyloxepan-2-ol was obtained.
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11

Paquet, Jacques, et Paul Brassard. « Reactions of polar dienes with o-quinones ». Canadian Journal of Chemistry 67, no 8 (1 août 1989) : 1354–58. http://dx.doi.org/10.1139/v89-207.

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The behaviour of various types of polar dienes towards halogenated ortho quinones has been investigated in a number of representative cases. As compared to the commonly used para analogues, o-quinones provide a wide range of products that indicate a keener response to the nature, number, and position of substituents on both reactants. 3-Halogenated-o-naphthoquinones 1 and 2 react smoothly with a representative vinologous ketene acetal 3, vinylketene acetals 4 and 5, and a monooxygenated diene 6 to provide variously substituted phenanthrenequinones 7–11. Only monooxygenated dienes on the other hand add to o-benzoquinones 14–16 and give convenient syntheses of the corresponding o-naphthoquinones 18–20. Keywords: cycloaddition, o-naphthoquinones, phenanthrenequinones, regiospecificity.
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12

Dussault, Patrick H., Tony K. Trullinger et Su Cho-Shultz. « Chiral Silyl Ketene Acetals from Thioesters : Reaction with Acetals and Peroxyacetals to form 3-Alkoxy- and 3-Peroxyalkanoates ». Tetrahedron 56, no 47 (novembre 2000) : 9213–20. http://dx.doi.org/10.1016/s0040-4020(00)00894-2.

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13

Kamitanaka, Tohru, Koji Morimoto, Toshifumi Dohi et Yasuyuki Kita. « Controlled-Coupling of Quinone Monoacetals by New Activation Methods : Regioselective Synthesis of Phenol-Derived Compounds ». Synlett 30, no 10 (25 mars 2019) : 1125–43. http://dx.doi.org/10.1055/s-0037-1611735.

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We have studied for a long time the reaction of quinone acetal type compounds, such as quinone monoacetals, quinone O,S-acetals, and iminoquinone monoacetals, and have reported the regioselective introduction of various nucleophiles. Quinone monoacetals show various types of reactivities toward nucleophiles due to their unique structures. In this study, we found that aromatic and alkene nucleophiles can be regioselectively introduced into the α-position of the carbonyl group on quinone monoacetals by specific activation of the acetal moiety. These reactions enabled the metal-free synthesis of highly functionalized aromatic compounds by the regioselective introduction of nucleophiles. In this account, we describe our recent studies of the coupling of quinone monoacetals.1 Introduction2 Regioselective Introduction of Aromatic Nucleophiles into α-Position of Carbonyl2.1 Biaryl Synthesis by Introduction of Aromatic Nucleophiles2.2 Synthesis of Terphenyls and Oligoarenes by Iterative Coupling2.3 Synthesis of Phenol Cross-Coupling Products3 [3+2] Coupling with Alkene Nucleophiles3.1 Development of Efficient [3+2] Coupling3.2 Improvement of Brønsted Acid Promotor4 Synthesis of α-Aryl Carbonyl Compounds Triggered by Silyl Transfer5 Utilization of o-Quinone Monoacetals6 Application to Iminoquinone Monoacetals7 Conclusion
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14

Vankar, Yashwant D., M. Venkatram Reddy et Narayan C. Chaudhuri. « Chiral acetals in organic synthesis : Regioselective synthesis of 2-and 3-hydroxy acetals from 2,3-olefinic acetals. Reinvestigation and further applications ». Tetrahedron 50, no 37 (janvier 1994) : 11057–78. http://dx.doi.org/10.1016/s0040-4020(01)85714-8.

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15

Isobe, Hiroyuki, Sota Sato, Takatsugu Tanaka, Hidetoshi Tokuyama et Eiichi Nakamura. « Thermal and Palladium-Catalyzed [3 + 2] Synthesis of Cyclopentadienone Acetals from Cyclopropenone Acetals and Acetylenes ». Organic Letters 6, no 20 (septembre 2004) : 3569–71. http://dx.doi.org/10.1021/ol0483450.

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16

Daia, G. Elena, Christopher D. Gabbutt, John D. Hepworth, B. Mark Heron, David E. Hibbs et Michael B. Hursthouse. « The directed lithiation of some 3-acylchromone acetals ». Tetrahedron Letters 39, no 10 (mars 1998) : 1215–18. http://dx.doi.org/10.1016/s0040-4039(97)10733-x.

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17

Dussault, Patrick H., Tony K. Trullinger et Su Cho-Shultz. « ChemInform Abstract : Chiral Silyl Ketene Acetals from Thioesters : Reaction with Acetals and Peroxyacetals to Form 3-Alkoxy- and 3-Peroxyalkanoates. » ChemInform 32, no 13 (27 mars 2001) : no. http://dx.doi.org/10.1002/chin.200113099.

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18

Evjen, Sigvart, et Anne Fiksdahl. « Gold(I)-catalysed [3+3] cycloaddition of propargyl acetals and nitrones ». Tetrahedron 72, no 23 (juin 2016) : 3270–76. http://dx.doi.org/10.1016/j.tet.2016.04.058.

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19

Ahmed, Owais, Vandana Cherkadu, Praveen Kumar Kalavagunta et Jing Shang. « Solvent-dependent regio- and stereo-selective reactions of 3-formylchromones with 2-aminobenzothiazoles and transacetalization efficiency of the product 3-((benzo[d]thiazol-2-ylimino)butyl)-4H-chromen-4-one ». RSC Advances 9, no 36 (2019) : 20573–81. http://dx.doi.org/10.1039/c9ra02763g.

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20

Devendar, Ponnam, Arigari Niranjana Kumar, M. S. Bethu, Amtul Zehra, R. Pamanji, J. Venkateswara Rao, Ashok Kumar Tiwari, Balasubramanian Sridhar, K. V. N. Satya Srinivas et J. Kotesh Kumar. « Highly selective one pot synthesis and biological evaluation of novel 3-(allyloxy)-propylidene acetals of some natural terpenoids ». RSC Advances 5, no 113 (2015) : 93122–30. http://dx.doi.org/10.1039/c5ra18517c.

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21

Sakai, Norio, Kazuki Sasaki, Hiroki Suzuki et Yohei Ogiwara. « One-Pot Synthesis of α-Halo β-Amino Acid Derivatives via the Difunctional Coupling of Ethyl α-Diazoacetate with Silyl Halides and N,O-Acetals or Aromatic Tertiary Amines ». Synthesis 52, no 12 (23 mars 2020) : 1823–32. http://dx.doi.org/10.1055/s-0039-1690864.

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The difunctionalization of ethyl α-diazoacetate (EDA) using silyl halides as a nucleophile and N,O-acetals as an electrophile under metal-free conditions is described. This process undergoes a novel three-component coupling (3-CC) reaction using EDA, which leads to a one-pot preparation of α-halo β-amino acid esters. Also, this protocol could be adapted to accept an electrophile composed of aromatic tertiary amines. In both 3-CC reactions, the key reaction intermediate is an iminium intermediate that can be easily and effectively generated either from N,O-acetals or from aromatic tertiary amines.
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22

Crosby, Ian T., Geoffrey A. Pietersz et Justin A. Ripper. « Synthesis of Succinimidoalkylbenzaldehyde Analogues : Potential Bifunctional Linkers for Bioconjugation ». Australian Journal of Chemistry 61, no 2 (2008) : 138. http://dx.doi.org/10.1071/ch07404.

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A series of novel 4-substituted benzaldehydes containing a succinimide moiety were synthesized as potential bifunctional linkers for the purpose of binding therapeutic drugs to antibodies raised against cancer cells. These potential benzaldehyde linkers varied in the nature of the para functionality so as to provide a range of potential acid labilities. Synthesis of the linkers involved a Williamson ether formation to make the ether linker 1, a Sonagoshira palladium-catalyzed coupling to synthesize the skeleton of the alkyl linker 2, and formation of an amide bond directly from a methyl ester gave the 4-substituted amide linker 3. As an example of the type of acetal that can be produced using these linkers, uridine was used as an analogue of the cytotoxic compound 5-fluorouridine to give the cyclic acetals 19–21.
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23

Kendall, Jackie D., et Paul D. Woodgate. « Towards the Diastereoselective Functionalization of Non-Racemic Acetal Derivatives of η6-Arylcarbonyl Complexes of Tricarbonylchromium ». Australian Journal of Chemistry 51, no 12 (1998) : 1083. http://dx.doi.org/10.1071/c98054.

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(S)-Butane-1,2,4-triol (2) has been investigated as a potential chiral auxiliary for the formation of non-racemic acetals derived from η6-arylcarbonyl complexes of tricarbonylchromium. Predominantly the cis dioxan (5) was formed from benzaldehyde, leading to preparation of the η6-Cr(CO)3 complex (16), and of the derived complexes (23) and (24). Lithiation{electrophile quenching of these complexes gave a mixture of products arising fromortho and benzylic functionalization. Reaction of acetophenone, or of the η6-Cr(CO)3 complexes (45) or (46), with either the triol (2) or its tris(silyl) ether (15) under conditions of kinetic or thermodynamic control gave an inseparable mixture of acetals.
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24

Motornov, Vladimir A., Andrey A. Tabolin, Roman A. Novikov, Yulia V. Nelyubina, Valentine G. Nenajdenko et Sema L. Ioffe. « Fluoronitroalkenes in tandem [4 + 1]/[3 + 2]-cycloaddition : one-pot three-component assembly of fluorinated bicyclic nitroso acetals ». Organic Chemistry Frontiers 5, no 17 (2018) : 2588–94. http://dx.doi.org/10.1039/c8qo00623g.

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25

Saget, Raphaël, Piotr Jaunky et Elisabet Duñach. « Bi(OTf)3-catalysed intramolecular cyclisation of unsaturated acetals ». RSC Advances 11, no 34 (2021) : 21066–72. http://dx.doi.org/10.1039/d1ra03686f.

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A series of highly functionalized carbocycles was efficiently prepared via the selective cyclisation of unsaturated acetals and ketals in the presence of only 1 mol% of Bi(iii) or Fe(iii) triflates as the catalysts at room temperature, with yields ranging from 60 to 90%.
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26

Vankar, Yashwant D., et Anita Bawa. « A Simple Synthesis of 3-Nitrocycloalkenones and their Acetals ». Synthetic Communications 15, no 14 (décembre 1985) : 1253–56. http://dx.doi.org/10.1080/00397918508077273.

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27

LYUBCHANSKAYA, V. M., et V. G. GRANIK. « ChemInform Abstract : Lactam Acetals and Acid Amide Acetals. Part 58. Novel Synthesis of 3- Nitro-5-hydroxybenzofurans. » ChemInform 22, no 5 (23 août 2010) : no. http://dx.doi.org/10.1002/chin.199105191.

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28

Antonova, Yulia A., Yulia V. Nelyubina, Sema L. Ioffe et Andrey A. Tabolin. « [3+3]-Annulation of Cyclic Nitronates with Vinyl Diazoacetates : Diastereoselective Synthesis of Partially Saturated [1,2]Oxazino[2,3-b][1,2]oxazines and Their Base-Promoted Ring Contraction to Pyrrolo[1,2-b][1,2]oxazine Derivatives ». Molecules 28, no 7 (28 mars 2023) : 3025. http://dx.doi.org/10.3390/molecules28073025.

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A rhodium(II)-catalyzed reaction of cyclic nitronates (5,6-dihydro-4H-1,2-oxazine N-oxides) with vinyl diazoacetates proceeds as a [3+3]-annulation producing bicyclic unsaturated nitroso acetals (4a,5,6,7-tetrahydro-2H-[1,2]oxazino[2,3-b][1,2]oxazines). Optimization of reaction conditions revealed the use of Rh(II) octanoate as the preferred catalyst in THF at room temperature, which allows the preparation of target products in good yields and excellent diastereoselectivity. Under basic conditions, namely, the combined action of DBU and alcohol, these nitroso acetals undergo ring contraction of an unsaturated oxazine ring into the corresponding pyrrole. Both transformations can be performed in a one-pot fashion, thus constituting a quick approach to oxazine-annulated pyrroles from available starting materials, such as nitroalkenes, olefins, and diazo compounds.
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29

Schiavo, Lucie, Loïc Jeanmart, Steve Lanners, Sabine Choppin et Gilles Hanquet. « FeCl3·6H2O/acetaldehyde, a versatile system for the deprotection of ketals and acetals via a transacetalization process ». New Journal of Chemistry 41, no 4 (2017) : 1421–24. http://dx.doi.org/10.1039/c6nj03439j.

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30

Radulović, Niko S., et Milan S. Nešić. « Diverse acetals from stoichiometric amounts of aldehydes and alcohols under very mild conditions : a new twist to PPh3–CCl4 reagent combination ». RSC Advances 6, no 95 (2016) : 93068–80. http://dx.doi.org/10.1039/c6ra19980a.

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31

Navarro, Cristina, Nathan D. Shapiro, Maurizio Bernasconi, Takahiro Horibe et F. Dean Toste. « Gold(I)-catalyzed enantioselective [3+2] and [3+3] cycloaddition reactions of propargyl acetals/ketals ». Tetrahedron 71, no 35 (septembre 2015) : 5800–5805. http://dx.doi.org/10.1016/j.tet.2015.04.109.

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Kim, Sunggak, Joo Hyeon Park et Joo Moon Lee. « Facile preparation of α,β-unsaturated O,S-acetals and mixed acetals via 3-alkoxy-2-alkenylenesulfonium salts. » Tetrahedron Letters 34, no 36 (septembre 1993) : 5769–72. http://dx.doi.org/10.1016/s0040-4039(00)73856-1.

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Srivastava, Abhijeet, Gaurav Shukla, Anugula Nagaraju, Girijesh Kumar Verma, Keshav Raghuvanshi, Raymond C. F. Jones et Maya Shankar Singh. « In(OTf)3-catalysed one-pot versatile pyrrole synthesis through domino annulation of α-oxoketene-N,S-acetals with nitroolefins ». Org. Biomol. Chem. 12, no 29 (2014) : 5484–91. http://dx.doi.org/10.1039/c4ob00781f.

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An operationally simple and efficient one-pot direct access to pyrroles has been achieved by annulation of α-oxoketene-N,S-acetals with β-nitrostyrenes catalyzed by In(OTf)3under solvent-free conditions.
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34

Gasparski, Catherine M., Paul M. Herrinton, Larry E. Overman et John P. Wolfe. « Synthesis of 3-acyltetrahydrofurans from formaldehyde acetals of allylic diols ». Tetrahedron Letters 41, no 49 (décembre 2000) : 9431–35. http://dx.doi.org/10.1016/s0040-4039(00)01571-9.

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Komeyama, Kimihiro, Ryoichi Igawa, Takayuki Morimoto et Ken Takaki. « Catalytic Cyclization of AlkenylN,O-Acetals by Fe(OTf)3 ». Chemistry Letters 38, no 7 (5 juillet 2009) : 724–25. http://dx.doi.org/10.1246/cl.2009.724.

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DAIA, G. E., C. D. GABBUTT, J. D. HEPWORTH, B. M. HERON, D. E. HIBBS et M. B. HURSTHOUSE. « ChemInform Abstract : The Directed Lithiation of Some 3-Acylchromone Acetals. » ChemInform 29, no 21 (22 juin 2010) : no. http://dx.doi.org/10.1002/chin.199821125.

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Guss, L. T., L. V. Ershov, G. A. Bogdanova et V. G. Granik. « Acetals of lactams and acid amides 55. Study of reaction of 3-oxopyridine and isoquinolin-3-one derivatives with dimethylformamide diethyl acetal ». Chemistry of Heterocyclic Compounds 26, no 2 (février 1990) : 183–88. http://dx.doi.org/10.1007/bf00499413.

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Cambie, RC, SE Holroyd, PS Rutledge et PD Woodgate. « Experiments Directed Towards the Synthesis of Anthracyclinones. XVII. Cyclization Reactions of Some Anthraquinone Conduritol Acetals ». Australian Journal of Chemistry 46, no 1 (1993) : 37. http://dx.doi.org/10.1071/ch9930037.

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Lewis acid induced intramolecular cyclization reactions of cyclohexenyl acetals derived from the condensation of the conduritol dimethyl ether (2) with the anthraquinone aldehyde (3) have been shown to give naphthacenediones as the only tetracyclic products.
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39

Liu, Yi-Wen, Rui-Jun Ma, Jia-Hang Yan, Zhu Zhou et Bang-Guo Wei. « Asymmetric synthesis of (−)-sedacryptine through a diastereoselective Mannich reaction of N,O-acetals with ketones ». Organic & ; Biomolecular Chemistry 16, no 5 (2018) : 771–79. http://dx.doi.org/10.1039/c7ob02989f.

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An approach to access the 3-hydroxyl-2,6-disubstituted piperidine scaffold has been developed through the Mannich process involving N,O-acetals and ketones, and the process is demonstrated by the asymmetric synthesis of (−)-sedacryptine.
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40

Somogyi, László. « Synthesis, oxidation and dehydrogenation of cyclicN,O- andN,S-Acetals. II . Transformation ofN,S-acetals : 3-Acylbenzothiazolines and -thiazolidines ». Journal of Heterocyclic Chemistry 43, no 5 (septembre 2006) : 1141–50. http://dx.doi.org/10.1002/jhet.5570430502.

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Löwe, Christiane, Gottfried Huttner, Laszlo Zsolnai et Heinz Berke. « Acetalisierte Formylmangan-Komplexe / Acetals of Formyl Manganese Complexes ». Zeitschrift für Naturforschung B 43, no 1 (1 janvier 1988) : 25–30. http://dx.doi.org/10.1515/znb-1988-0106.

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Abstract Acetal complexes of the type (OC)5 MnCH(XR)2 , RX = PhO (1a), (RX)2 = 1,2-dioxybenzene (1b), (RX), = S-(CH2)3-S (2) and (5) were synthesized. Glyoxyloyl acetal derivatives (OC)5 MnC(O)CH(XR)2, RX = PhO (3a), (RX)2 = 1,2-dioxybenzene (3b), (RX)2 = S-(CH2)3-S (4) were obtained by the action of NaMn(CO)5 upon the corresponding acid chlorides or anhydrides, la can be transformed to 3a by CO insertion, 1a has been characterized by an X-ray structure determination.
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42

Möhrle, Hans, et Heinz Dwuletzki. « Lactamacetale als potentielle Enamin-Synthone in Heterocyclensynthesen, 4. Mitteilung Einstufen-Synthese des γ-Carbolingerüsts durch Diels-Alder-Reaktion von Indol-„Keten-N,O-acetalen“/ Lactam Acetals as Potential Enamine Synthons in Heterocyclic Synthesis, 4th Communication. One Step Synthesis of the γ-Carboline Frame via Diels-Alder Reaction of Indol-“Ketene-N.O-Acetals” ». Zeitschrift für Naturforschung B 42, no 8 (1 août 1987) : 1032–34. http://dx.doi.org/10.1515/znb-1987-0818.

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Abstract2-Alkoxy-indoles 2a, b can be regarded as cyclic ketene-N.O -acetals. Their regiospecific [4+2]- Diels-Alder reaction with inverse electron demand with the triazine 3 yield in a one step addition the γ-carboline (4).
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43

VANKAR, Y. D., M. V. REDDY et N. C. CHAUDHURI. « ChemInform Abstract : Asymmetric Synthesis. Part 2. Chiral Acetals in Organic Synthesis : Regioselective Synthesis of 2- and 3-Hydroxy Acetals from 2,3-Olefinic Acetals. Reinvestigation and Further Applications. » ChemInform 26, no 8 (18 août 2010) : no. http://dx.doi.org/10.1002/chin.199508076.

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Xiao, Tiebo, Ping Zhang, Yang Xie, Jun Wang et Lei Zhou. « CuI-catalyzed cross-coupling of terminal alkynes with dialkoxycarbenes : a general method for the synthesis of unsymmetrical propargylic acetals ». Org. Biomol. Chem. 12, no 32 (2014) : 6215–22. http://dx.doi.org/10.1039/c4ob00614c.

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A general source of dialkoxycarbenes, 2,2-dialkoxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines, have been successfully employed as coupling partners in CuI-catalyzed cross-coupling reactions with terminal alkynes, which afforded various unsymmetrical propargylic acetals in good yields.
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45

Dussault, P. H., R. J. Lee, J. A. Schultz et Y. S. Suh. « Reaction of peroxyacetals with silyl ketene acetals : synthesis of 3-peroxyalkanoates and 3-peroxyalkanals ». Tetrahedron Letters 41, no 29 (juillet 2000) : 5457–60. http://dx.doi.org/10.1016/s0040-4039(00)00914-x.

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46

Gupta, Akhilesh K., R. T. Chakrasali, H. Ila et H. Junjappa. « Reaction of Polarized KeteneS,N-Acetals with Bromoacetaldehyde Diethyl Acetal : Synthesis of 1-Substituted 3-Acyl- and 3-Nitro-2-methylthiopyrroles and 1,2-Annulated 3-Acylpyrroles ». Synthesis 1989, no 02 (1989) : 141–42. http://dx.doi.org/10.1055/s-1989-27179.

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Cao, Zhicheng, Xin Deng, Chao Chen, Yonghong Liu, Lei Yu et Xuefeng Jiang. « Synergetic catalysis of Se and Cu allowing diethoxylation of halomethylene ketones using O2 as the mild oxidant ». Reaction Chemistry & ; Engineering 6, no 3 (2021) : 454–58. http://dx.doi.org/10.1039/d0re00471e.

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Catalyzed by PhSe(O)OH/Cu(OAc)2, sp3-C–H alkylation of bromomethylene ketones produced useful α-carbonyl acetals under mild conditions. Bromo-containing substrates could release HBr during the reaction, avoiding the use of acidic additives.
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48

Lyu, Longyun, Ming Yu Jin, Qijie He, Han Xie, Zhaoxiang Bian et Jun Wang. « Bi(OTf)3-catalyzed addition of isocyanides to 2H-chromene acetals : an efficient pathway for accessing 2-carboxamide-2H-chromenes ». Organic & ; Biomolecular Chemistry 14, no 34 (2016) : 8088–91. http://dx.doi.org/10.1039/c6ob01355d.

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Bismuth triflate (Bi(OTf)3) is identified as an efficient catalyst for the direct addition of isocyanides to 2H-chromene acetals. By this synthetic strategy, a polyfunctional molecular scaffold, 2-carboxamide-2H-chromenes could be prepared efficiently in one step with up to 95% yields.
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49

KIM, S., J. H. PARK et J. M. LEE. « ChemInform Abstract : Facile Preparation of α,β-Unsaturated O,S-Acetals and Mixed Acetals via 3-Alkoxy-2-alkenylenesulfonium Salts. » ChemInform 24, no 48 (20 août 2010) : no. http://dx.doi.org/10.1002/chin.199348107.

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Huang, Yong Kui, Li Yu, Guo Bin Duan, Yun Zhi Wang, Ming Bo Xu et Shui Jin Yang. « Catalytic Application of H3PW6Mo6O40/SiO2 in Synthesis of Acetals and Ketals ». Advanced Materials Research 531 (juin 2012) : 304–7. http://dx.doi.org/10.4028/www.scientific.net/amr.531.304.

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A novel catalyst, H3PW6Mo6O40/SiO2was prepared by a sol-gel technique and its catalytic application in synthesis of acetals and ketals were tested. The preparation conditions of catalyst were optimised by using the orthogonal experimental design. The optimum conditions are: the mass ratio of H3PW6Mo6O40 to SiO2is 0.4, calcination temperature is 150 °C and calcination time is 3 h. The steric properties of the reactants play an important role in the acetalization. The catalytic activity of the catalyst decreases when the size of the reactant increased. Although a decrease in catalytic activity was observed with its subsequent reuse, the catalyst could be reused at least four times without any other treatments. The results reveal that the H3PW6Mo6O40/SiO2catalysis generally results in good yields of acetals and ketals under mild reaction conditions.
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