The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Masami Kamigaito - One of the best experts on this subject based on the ideXlab platform.
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thiol ene cationic and radical reactions for 1 1 addition cyclization step growth polymerization and concurrent polymerization producing thioacetal and Thioether units
Angewandte Chemie, 2020Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masahiro Osumi, Masami KamigaitoAbstract:: Thiol-ene cationic and radical reactions were conducted for 1:1 addition between a thiol and vinyl ether, and also for cyclization and step-growth polymerization between a dithiol and divinyl ether. p-Toluenesulfonic acid (PTSA) induced a cationic thiol-ene reaction to generate a thioacetal in high yield, whereas 2,2'-azobisisobutyronitrile resulted in a radical thiol-ene reaction to give a Thioether, also in high yield. The cationic and radical addition reactions between a dithiol and divinyl ether with oxyethylene units yielded amorphous poly(thioacetal)s and crystalline poly(Thioether)s, respectively. Under high-dilution conditions, the cationic and radical reactions resulted in 16- and 18-membered cyclic thioacetal and Thioether products, respectively. Furthermore, concurrent cationic and radical step-growth polymerizations were realized using PTSA under UV irradiation to produce polymers having both thioacetal and Thioether linkages in the main chain.
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Thioether mediated degenerative chain transfer cationic polymerization a simple metal free system for living cationic polymerization
Macromolecules, 2015Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masami KamigaitoAbstract:Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of Thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable Thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2═CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, Thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective...
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Thioether-Mediated Degenerative Chain-Transfer Cationic Polymerization: A Simple Metal-Free System for Living Cationic Polymerization
2015Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masami KamigaitoAbstract:Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of Thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable Thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, Thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective. A silyl-protected difunctional diThioether produced telechelic polymers possessing hydroxyl groups at both chain ends and stable thiol linkers in the middle of the polymer chains. These polymers were subsequently used in chain-extension reactions in conjunction with diisocyanates and diols as chain extenders to be converted into high molecular weight polymers linked via urethane linkages
Xuefeng Jiang - One of the best experts on this subject based on the ideXlab platform.
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ligand controlled divergent cross coupling involving organosilicon compounds for Thioether and thioester synthesis
Organic Letters, 2016Co-Authors: Zongjun Qiao, Xuefeng JiangAbstract:A divergent cross-coupling for both Thioether and thioester construction from organosilicon compounds has been developed. Predominant selectivity for Hiyama-type coupling and C1 insertion reaction was achieved under the guidance of ligands. Thioether was obtained under ligand-free conditions in which disulfide generated from homocoupling could be prevented. Meanwhile, application of bidentate phosphine ligands under carbon monoxide atmosphere (CO balloon) afforded the thioester with little decomposition, which was revealed through interval NMR tracking.
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Ligand-Controlled Divergent Cross-Coupling Involving Organosilicon Compounds for Thioether and Thioester Synthesis
2016Co-Authors: Zongjun Qiao, Xuefeng JiangAbstract:A divergent cross-coupling for both Thioether and thioester construction from organosilicon compounds has been developed. Predominant selectivity for Hiyama-type coupling and C1 insertion reaction was achieved under the guidance of ligands. Thioether was obtained under ligand-free conditions in which disulfide generated from homocoupling could be prevented. Meanwhile, application of bidentate phosphine ligands under carbon monoxide atmosphere (CO balloon) afforded the thioester with little decomposition, which was revealed through interval NMR tracking
Mineto Uchiyama - One of the best experts on this subject based on the ideXlab platform.
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thiol ene cationic and radical reactions for 1 1 addition cyclization step growth polymerization and concurrent polymerization producing thioacetal and Thioether units
Angewandte Chemie, 2020Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masahiro Osumi, Masami KamigaitoAbstract:: Thiol-ene cationic and radical reactions were conducted for 1:1 addition between a thiol and vinyl ether, and also for cyclization and step-growth polymerization between a dithiol and divinyl ether. p-Toluenesulfonic acid (PTSA) induced a cationic thiol-ene reaction to generate a thioacetal in high yield, whereas 2,2'-azobisisobutyronitrile resulted in a radical thiol-ene reaction to give a Thioether, also in high yield. The cationic and radical addition reactions between a dithiol and divinyl ether with oxyethylene units yielded amorphous poly(thioacetal)s and crystalline poly(Thioether)s, respectively. Under high-dilution conditions, the cationic and radical reactions resulted in 16- and 18-membered cyclic thioacetal and Thioether products, respectively. Furthermore, concurrent cationic and radical step-growth polymerizations were realized using PTSA under UV irradiation to produce polymers having both thioacetal and Thioether linkages in the main chain.
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Thioether mediated degenerative chain transfer cationic polymerization a simple metal free system for living cationic polymerization
Macromolecules, 2015Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masami KamigaitoAbstract:Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of Thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable Thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2═CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, Thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective...
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Thioether-Mediated Degenerative Chain-Transfer Cationic Polymerization: A Simple Metal-Free System for Living Cationic Polymerization
2015Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masami KamigaitoAbstract:Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of Thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable Thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, Thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective. A silyl-protected difunctional diThioether produced telechelic polymers possessing hydroxyl groups at both chain ends and stable thiol linkers in the middle of the polymer chains. These polymers were subsequently used in chain-extension reactions in conjunction with diisocyanates and diols as chain extenders to be converted into high molecular weight polymers linked via urethane linkages
Zongjun Qiao - One of the best experts on this subject based on the ideXlab platform.
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ligand controlled divergent cross coupling involving organosilicon compounds for Thioether and thioester synthesis
Organic Letters, 2016Co-Authors: Zongjun Qiao, Xuefeng JiangAbstract:A divergent cross-coupling for both Thioether and thioester construction from organosilicon compounds has been developed. Predominant selectivity for Hiyama-type coupling and C1 insertion reaction was achieved under the guidance of ligands. Thioether was obtained under ligand-free conditions in which disulfide generated from homocoupling could be prevented. Meanwhile, application of bidentate phosphine ligands under carbon monoxide atmosphere (CO balloon) afforded the thioester with little decomposition, which was revealed through interval NMR tracking.
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Ligand-Controlled Divergent Cross-Coupling Involving Organosilicon Compounds for Thioether and Thioester Synthesis
2016Co-Authors: Zongjun Qiao, Xuefeng JiangAbstract:A divergent cross-coupling for both Thioether and thioester construction from organosilicon compounds has been developed. Predominant selectivity for Hiyama-type coupling and C1 insertion reaction was achieved under the guidance of ligands. Thioether was obtained under ligand-free conditions in which disulfide generated from homocoupling could be prevented. Meanwhile, application of bidentate phosphine ligands under carbon monoxide atmosphere (CO balloon) afforded the thioester with little decomposition, which was revealed through interval NMR tracking
Kotaro Satoh - One of the best experts on this subject based on the ideXlab platform.
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thiol ene cationic and radical reactions for 1 1 addition cyclization step growth polymerization and concurrent polymerization producing thioacetal and Thioether units
Angewandte Chemie, 2020Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masahiro Osumi, Masami KamigaitoAbstract:: Thiol-ene cationic and radical reactions were conducted for 1:1 addition between a thiol and vinyl ether, and also for cyclization and step-growth polymerization between a dithiol and divinyl ether. p-Toluenesulfonic acid (PTSA) induced a cationic thiol-ene reaction to generate a thioacetal in high yield, whereas 2,2'-azobisisobutyronitrile resulted in a radical thiol-ene reaction to give a Thioether, also in high yield. The cationic and radical addition reactions between a dithiol and divinyl ether with oxyethylene units yielded amorphous poly(thioacetal)s and crystalline poly(Thioether)s, respectively. Under high-dilution conditions, the cationic and radical reactions resulted in 16- and 18-membered cyclic thioacetal and Thioether products, respectively. Furthermore, concurrent cationic and radical step-growth polymerizations were realized using PTSA under UV irradiation to produce polymers having both thioacetal and Thioether linkages in the main chain.
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Thioether mediated degenerative chain transfer cationic polymerization a simple metal free system for living cationic polymerization
Macromolecules, 2015Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masami KamigaitoAbstract:Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of Thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable Thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2═CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, Thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective...
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Thioether-Mediated Degenerative Chain-Transfer Cationic Polymerization: A Simple Metal-Free System for Living Cationic Polymerization
2015Co-Authors: Mineto Uchiyama, Kotaro Satoh, Masami KamigaitoAbstract:Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of Thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable Thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, Thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective. A silyl-protected difunctional diThioether produced telechelic polymers possessing hydroxyl groups at both chain ends and stable thiol linkers in the middle of the polymer chains. These polymers were subsequently used in chain-extension reactions in conjunction with diisocyanates and diols as chain extenders to be converted into high molecular weight polymers linked via urethane linkages
