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M Penso - One of the best experts on this subject based on the ideXlab platform.
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regioselective o sulfonylation of n n bis 2 hydroxyalkyl tosylamides as a synthetic key step to enantiopure morpholines
Organic Letters, 2017Co-Authors: Francesca Foschi, Domenico Albanese, Ilir Pecnikaj, Aaron Tagliabue, M PensoAbstract:The synthesis of enantiopure 2,6-disubstituted morpholines was realized through sequential ring opening of two different optically pure Oxiranes by a tosylamide, under solid–liquid phase-transfer catalysis (SL-PTC) conditions, mono-O-sulfonylation of the resulting tosylamido-2,2′-diol, and cyclization to the morpholine. The crucial step, the regioselective formation of the monosulfonate, was controlled by taking advantage of the different stereo, electronic, and coordination properties of the Oxirane-derived side chains in the diol backbone. As an application of this protocol, a new morpholine-3-carboxamide was synthesized starting from threonine.
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Regioselective O‑Sulfonylation of N,N‑Bis(2-hydroxyalkyl)tosylamides as a Synthetic Key Step to Enantiopure Morpholines
2016Co-Authors: Francesca Foschi, Domenico Albanese, Ilir Pecnikaj, Aaron Tagliabue, M PensoAbstract:The synthesis of enantiopure 2,6-disubstituted morpholines was realized through sequential ring opening of two different optically pure Oxiranes by a tosylamide, under solid–liquid phase-transfer catalysis (SL-PTC) conditions, mono-O-sulfonylation of the resulting tosylamido-2,2′-diol, and cyclization to the morpholine. The crucial step, the regioselective formation of the monosulfonate, was controlled by taking advantage of the different stereo, electronic, and coordination properties of the Oxirane-derived side chains in the diol backbone. As an application of this protocol, a new morpholine-3-carboxamide was synthesized starting from threonine
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a straightforward synthesisof enantiopure 2 6 disubstituted morpholines by a regioselectiveo protection activation protocol
Synlett, 2008Co-Authors: M Penso, Francesca Foschi, Domenico Albanese, Vittoria Lupi, Dario Landini, Aaron TagliabueAbstract:: Enantiopure 2,6-disubstituted morpholines have been synthesized through the ring opening of chiral, nonracemic Oxiranes with nitrogen nucleophiles, under solid-liquid phase-transfer catalysis (SL-PTC) conditions. The β-hydroxytosyi amides resulting from the ring opening of a first epoxide with TsNH 2 was used as nucleophile, after protection of the hydroxyl group, in the reaction with a second Oxirane. The morpholine skeleton has been generated through standard functional group chemistry, followed by cyclization of the intermediate p-hydroxy-β'-tosyloxy-tosylamides carried out under SL-PTC conditions. N-Tosyl morpholines produced can be employed as building blocks in the synthesis of pharmaceuticals and as chiral tools.
Sadahito Aoshima - One of the best experts on this subject based on the ideXlab platform.
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Copolymerizability Evaluation in Cationic Vinyl-Addition and Ring-Opening Copolymerization of Vinyl Ethers and Oxiranes: Effects of Bulkiness and the Number of Substituents Introduced into Oxiranes
'American Chemical Society (ACS)', 2021Co-Authors: Yui Kawamura, Arihiro Kanazawa, Daisuke Hotta, Sadahito AoshimaAbstract:The kinds of alkyl substituents and the number of substituents were demonstrated to affect the reactivity of Oxiranes in the cationic copolymerization with alkyl vinyl ethers. A series of di-, tri-, or tetrasubstituted Oxiranes with two alkyl groups at the 2-position, which generate a tertiary carbocation by ring opening, were designed and synthesized. When 2,2-dialkyl-substituted Oxiranes with a methyl group and a propyl, isopropyl, or neopentyl group at the 2-position were copolymerized with isopropyl vinyl ether, the incorporated amounts of Oxiranes into copolymer chains decreased in this order, which indicates that Oxiranes with bulkier substituents exhibit a lower reactivity. The order of the reactivities of these Oxiranes in copolymerization was also consistent with the reactivity in methanolysis by an acid catalyst. In addition, the bulkiness of the substituent at the 3-position of trisubstituted Oxiranes with two methyl groups at the 2-position affected the reactivity in copolymerization in a manner similar to that of the disubstituted Oxiranes. Tetrasubstituted Oxiranes were also examined; however, insoluble products were obtained or Oxiranes were not incorporated into polymer chains. Oxiranes with six- or five-membered fused ring structures, such as limonene oxide, exhibited relatively high reactivities. The results obtained in this study can lead to a systematic understanding of the polymerizability of Oxiranes
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Cationic Ring-Opening Co- and Terpolymerizations of Lactic Acid-Derived 1,3-Dioxolan-4-ones with Oxiranes and Vinyl Ethers: Nonhomopolymerizable Monomer for Degradable Co- and Terpolymers
2019Co-Authors: Kano Hyoi, Arihiro Kanazawa, Sadahito AoshimaAbstract:Lactic acid-derived 1,3-dioxolan-4-ones (DOLOs), which do not undergo cationic homopolymerization, were demonstrated to yield copolymers with Oxiranes through a cationic copolymerization via frequent crossover reactions. Acetal and ester moieties were generated in the main chain of the copolymers via crossover reactions from DOLO to Oxirane and from Oxirane to DOLO, respectively, which is in contrast to the unsuccessful generation of hemiacetal ester moieties in the homopropagation of DOLO. In addition, the terpolymerization of DOLO, Oxirane, and vinyl ether (VE) proceeded via crossover reactions, while copolymers could not be generated from VE and DOLO in the absence of Oxirane. The obtained co- and terpolymers could be degraded under acidic conditions due to the acetal moieties in the main chain. The strategy devised in this study shows a promising avenue for employing plant-derived “nonhomopolymerizable” compounds as building blocks for the synthesis of degradable co- and terpolymers with general-purpose monomers
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exclusive one way cycle sequence control in cationic terpolymerization of general purpose monomers via concurrent vinyl addition ring opening and carbonyl addition mechanisms
ACS Macro Letters, 2015Co-Authors: Arihiro Kanazawa, Sadahito AoshimaAbstract:Cationic terpolymerization of vinyl ether (VE), Oxirane, and ketone successfully proceeded via unprecedented concurrent vinyl-addition, ring-opening, and carbonyl-addition mechanisms. In particular, the use of cyclohexene oxide as an Oxirane resulted in terpolymerization via an exclusive one-way cycle, i.e., the reactions occurred only in the VE → Oxirane, Oxirane → ketone, and ketone → VE directions. Terpolymers that have repeating units of (VE∼2–Oxirane∼2–ketone)n were obtained under appropriate conditions. In addition, no two-monomer combination achieved efficient copolymerization, which suggests that three specific types of crossover reactions are required for successful terpolymerization. The presence of a ketone, a compound that has rarely been employed as a monomer, is indispensable for a one-way cycle: terpolymerization also proceeded with an aliphatic aldehyde but resulted in two-way crossover reactions at the aldehyde-derived propagating ends.
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Exclusive One-Way Cycle Sequence Control in Cationic Terpolymerization of General-Purpose Monomers via Concurrent Vinyl-Addition, Ring-Opening, and Carbonyl-Addition Mechanisms
2015Co-Authors: Arihiro Kanazawa, Sadahito AoshimaAbstract:Cationic terpolymerization of vinyl ether (VE), Oxirane, and ketone successfully proceeded via unprecedented concurrent vinyl-addition, ring-opening, and carbonyl-addition mechanisms. In particular, the use of cyclohexene oxide as an Oxirane resulted in terpolymerization via an exclusive one-way cycle, i.e., the reactions occurred only in the VE → Oxirane, Oxirane → ketone, and ketone → VE directions. Terpolymers that have repeating units of (VE∼2–Oxirane∼2–ketone)n were obtained under appropriate conditions. In addition, no two-monomer combination achieved efficient copolymerization, which suggests that three specific types of crossover reactions are required for successful terpolymerization. The presence of a ketone, a compound that has rarely been employed as a monomer, is indispensable for a one-way cycle: terpolymerization also proceeded with an aliphatic aldehyde but resulted in two-way crossover reactions at the aldehyde-derived propagating ends
Fushun Liang - One of the best experts on this subject based on the ideXlab platform.
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synthesis of spiro isoquinolinone 4 2 Oxiranes and isoindolinones via a multicomponent reaction of 2 acetyl Oxirane 2 carboxamides arylaldehydes and malononitrile
ChemInform, 2014Co-Authors: Bing Liu, Enxiang Wei, Shaoxia Lin, Baozhong Zhao, Fushun LiangAbstract:Depending on different intramolecular hydrogen bonding modes in diastereomeric 2-acetyl-Oxirane-2-carboxamides (I) and (V), title compounds (IV) and (VI), resp., are formed in the multicomponent reaction with aryl aldehydes (II) and malodinitrile (III).
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synthesis of spiro isoquinolinone 4 2 Oxiranes and isoindolinones via a multicomponent reaction of 2 acetyl Oxirane 2 carboxamides arylaldehydes and malononitrile
Chemical Communications, 2014Co-Authors: Bing Liu, Enxiang Wei, Shaoxia Lin, Baozhong Zhao, Fushun LiangAbstract:Efficient synthesis of spiro[isoquinolinone-4,2′-Oxiranes] was achieved based on a multicomponent one-pot reaction of readily available cis-2-acetyl-Oxirane-2-carboxamides, arylaldehydes and malononitrile at room temperature. However, in the reaction with trans-2-acetyl-Oxirane-2-carboxamide substrates, 3-iminoisoindolinones were obtained in moderate to high yields.
Aaron Tagliabue - One of the best experts on this subject based on the ideXlab platform.
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regioselective o sulfonylation of n n bis 2 hydroxyalkyl tosylamides as a synthetic key step to enantiopure morpholines
Organic Letters, 2017Co-Authors: Francesca Foschi, Domenico Albanese, Ilir Pecnikaj, Aaron Tagliabue, M PensoAbstract:The synthesis of enantiopure 2,6-disubstituted morpholines was realized through sequential ring opening of two different optically pure Oxiranes by a tosylamide, under solid–liquid phase-transfer catalysis (SL-PTC) conditions, mono-O-sulfonylation of the resulting tosylamido-2,2′-diol, and cyclization to the morpholine. The crucial step, the regioselective formation of the monosulfonate, was controlled by taking advantage of the different stereo, electronic, and coordination properties of the Oxirane-derived side chains in the diol backbone. As an application of this protocol, a new morpholine-3-carboxamide was synthesized starting from threonine.
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Regioselective O‑Sulfonylation of N,N‑Bis(2-hydroxyalkyl)tosylamides as a Synthetic Key Step to Enantiopure Morpholines
2016Co-Authors: Francesca Foschi, Domenico Albanese, Ilir Pecnikaj, Aaron Tagliabue, M PensoAbstract:The synthesis of enantiopure 2,6-disubstituted morpholines was realized through sequential ring opening of two different optically pure Oxiranes by a tosylamide, under solid–liquid phase-transfer catalysis (SL-PTC) conditions, mono-O-sulfonylation of the resulting tosylamido-2,2′-diol, and cyclization to the morpholine. The crucial step, the regioselective formation of the monosulfonate, was controlled by taking advantage of the different stereo, electronic, and coordination properties of the Oxirane-derived side chains in the diol backbone. As an application of this protocol, a new morpholine-3-carboxamide was synthesized starting from threonine
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a straightforward synthesisof enantiopure 2 6 disubstituted morpholines by a regioselectiveo protection activation protocol
Synlett, 2008Co-Authors: M Penso, Francesca Foschi, Domenico Albanese, Vittoria Lupi, Dario Landini, Aaron TagliabueAbstract:: Enantiopure 2,6-disubstituted morpholines have been synthesized through the ring opening of chiral, nonracemic Oxiranes with nitrogen nucleophiles, under solid-liquid phase-transfer catalysis (SL-PTC) conditions. The β-hydroxytosyi amides resulting from the ring opening of a first epoxide with TsNH 2 was used as nucleophile, after protection of the hydroxyl group, in the reaction with a second Oxirane. The morpholine skeleton has been generated through standard functional group chemistry, followed by cyclization of the intermediate p-hydroxy-β'-tosyloxy-tosylamides carried out under SL-PTC conditions. N-Tosyl morpholines produced can be employed as building blocks in the synthesis of pharmaceuticals and as chiral tools.
Arturo Espinosa Ferao - One of the best experts on this subject based on the ideXlab platform.
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on the mechanism of trimethylphosphine mediated reductive dimerization of ketones
Inorganic Chemistry, 2018Co-Authors: Arturo Espinosa FeraoAbstract:High-level single-reference calculations reveal that trimethylphosphine-mediated reductive dimerization of properly substituted (e.g., CF3) ketones proceeds via initial formation of an oxaphosphirane intermediate, with the oxygen atom occupying an equatorial position at phosphorus. In the “Oxirane route”, this oxaphosphirane intermediate loses a trimethylphosphine oxide unit, thus behaving as a carbene transfer agent toward a second carbonyl molecule and giving rise to a carbonyl ylide that cyclizates to the corresponding Oxirane. This in turn transfers the carbene unit to a second phosphine molecule, with loss of acetone, affording a phosphorane. The latter undergoes typical Wittig reaction to the final homocoupling product through the oxaphosphetane intermediate. The alternative direct conversion of oxaphosphirane into phosphorane constitutes the lowest energy path as it skips the highest barrier Oxirane → phosphorane conversion. The Oxirane route is favored by the use of polar solvents and electron def...
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On the Mechanism of Trimethylphosphine-Mediated Reductive Dimerization of Ketones
2018Co-Authors: Arturo Espinosa FeraoAbstract:High-level single-reference calculations reveal that trimethylphosphine-mediated reductive dimerization of properly substituted (e.g., CF3) ketones proceeds via initial formation of an oxaphosphirane intermediate, with the oxygen atom occupying an equatorial position at phosphorus. In the “Oxirane route”, this oxaphosphirane intermediate loses a trimethylphosphine oxide unit, thus behaving as a carbene transfer agent toward a second carbonyl molecule and giving rise to a carbonyl ylide that cyclizates to the corresponding Oxirane. This in turn transfers the carbene unit to a second phosphine molecule, with loss of acetone, affording a phosphorane. The latter undergoes typical Wittig reaction to the final homocoupling product through the oxaphosphetane intermediate. The alternative direct conversion of oxaphosphirane into phosphorane constitutes the lowest energy path as it skips the highest barrier Oxirane → phosphorane conversion. The Oxirane route is favored by the use of polar solvents and electron deficient carbonyl components. The lowest barrier most exergonic process from oxaphosphirane is the pericyclic cycloaddition of the acetone CO bond along the endocyclic P–C bond, furnishing the stable 1,3,2-dioxaphospholane product
