The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
Tadashi Narita - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of novel fluorinated polymers: facile carbon–carbon bond formation aided by fluorine substituents
Polymer Journal, 2011Co-Authors: Tadashi NaritaAbstract:The footprints of a macromolecular synthetic chemist were left on the sands of time. Novel anionic addition polymerization of fluorinated Vinyl monomers, which generally show poor homopolymerization reactivity, has been developed. Anionic polyaddition has been achieved by the double Michael addition of bis(2-trifluoromethylacrylate)s to active methylene Compounds. Radical addition of fluorinated Vinyl monomers with many organic Compounds possessing carbon–hydrogen bonds has been accomplished and amplified to the polyaddition reaction to incorporate fluorinated Vinyl monomers into polymer main chains. The facile carbon–carbon bond formation reactions have been accomplished by the aid of fluorine substituents. The review article summarizes my work as a macromolecular synthetic chemist to leave it on the sands of time. Fluorinated Vinyl Compounds with high addition reactivities toward anionic and radical species were demonstrated to allow facile preparation of fluorinated polymers. Novel anionic addition polymerization of fluorinated Vinyl monomers, which generally show poor homopolymerization reactivities under radical conditions, has been developed. Measurement of pseudo first-order rate constants, k ′, demonstrated the order of reactivity of 18 fluorinated acrylates and methacrylates by the reaction with diethyl(ethyl cyanoacetato)aluminum. The new field, anionic polyaddition, was accomplished by the double Michael addition of bis(2-trifluoromethylacrylate)s to active methylene Compounds. Radical addition reaction of several fluorinated Vinyl Compounds with organic Compounds possessing carbon–hydrogen bonds afforded fluorinated organic Compounds. By developing the novel radical addition, the polyaddition reaction was achieved to incorporate fluorinated Vinyl monomers into polymer main chains with organic Compounds possessing carbon–hydrogen bonds, the first use for these polymers as starting materials of macromolecular syntheses. Facile carbon–carbon bond formation reactions were made possible with the aid of fluorine substituents under anionic and radical conditions. These reactions were then developed into the formation of the carbon–carbon bond from a carbon–hydrogen bond as a functional group in aliphatic Compounds.
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Stimulation on the addition reactivity of fluorinated Vinyl monomers—Facile carbon–carbon bond formation by the aid of fluorine substituents
Journal of Fluorine Chemistry, 2010Co-Authors: Tadashi NaritaAbstract:Abstract The high addition reactivity of fluorinated Vinyl Compounds toward radical and anionic species was demonstrated to afford facile methods for the carbon–carbon bond formation by the aid of fluorinated substituents of Vinyl groups. Some of the reactions are proved to be applicable to the preparation of polymers by radical or anionic polyaddition reaction mechanism. The investigation on the anionic reactivity order of fluorinated acrylates and methacrylates may contribute to the development in the field of the estimation by the computer chemistry to determine which effect of the fluorine-substitution would control the reactions.
S. V. Kurmaz - One of the best experts on this subject based on the ideXlab platform.
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State-of-the-art in the studies of three-dimensional radical copolymerisation
Russian Chemical Reviews, 2004Co-Authors: Valentin P. Roshchupkin, S. V. KurmazAbstract:The state-of-the art in the study of three-dimensional radical copolymerisation of multifunctional Vinyl Compounds with various monomers has been analysed. The mechanisms of relationships between copolymerisation kinetics with structure-physical transformations of the reaction medium and structures of cross-linked polymers are discussed. The key role of spectroscopic monitoring methods in the in situ studies of structure–kinetics relationships in three-dimensional radical copolymerisation is demonstrated. New approaches to control over these processes based on the use of chain transfer catalysis and living radical polymerisation are considered. The bibliography includes 178 references.
Toshinobu Higashimura - One of the best experts on this subject based on the ideXlab platform.
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The nature of propagating species in cationic polymerization of Vinyl Compounds
Journal of Polymer Science: Polymer Symposia, 2007Co-Authors: Toshinobu HigashimuraAbstract:A suitable combination of the stability of propagating carbocation and the nucleophilicity of counterion is necessary in general for the formation of polymers with a bimodal molecular weight distribution: for styrene or p-chlorostyrene, less nucleophilic counterions (ClO4−, CF3SO3−) are suitable; for p-methyl-or p-methoxystryene, highly nucleophilic I3− or I− is required. In the styrene polymerization with ClO4− or CF3SO3− as counterion, the common-ion salt effect on the molecular weight distribution and the steric structure of the polymer suggest that two kinds of ion pairs as well as free ions are involved in the cationic polymerization. These species have been found to be different not only in reactivity in homopolymerization but also in monomer selectivity in copolymerization.
Valentin P. Roshchupkin - One of the best experts on this subject based on the ideXlab platform.
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State-of-the-art in the studies of three-dimensional radical copolymerisation
Russian Chemical Reviews, 2004Co-Authors: Valentin P. Roshchupkin, S. V. KurmazAbstract:The state-of-the art in the study of three-dimensional radical copolymerisation of multifunctional Vinyl Compounds with various monomers has been analysed. The mechanisms of relationships between copolymerisation kinetics with structure-physical transformations of the reaction medium and structures of cross-linked polymers are discussed. The key role of spectroscopic monitoring methods in the in situ studies of structure–kinetics relationships in three-dimensional radical copolymerisation is demonstrated. New approaches to control over these processes based on the use of chain transfer catalysis and living radical polymerisation are considered. The bibliography includes 178 references.
Shin-ichiro Shoda - One of the best experts on this subject based on the ideXlab platform.
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Efficient generation of thiolate sugars from glycosyl Bunte salts and its application to S-glycoside synthesis
Tetrahedron Letters, 2020Co-Authors: Yasuhiro Meguro, Masato Noguchi, Shin-ichiro ShodaAbstract:Abstract A one-pot aqueous solution method for synthesis of S-glycoside derivatives has been developed. Firstly, unprotected sugars were converted into glycosyl Bunte salts from which thiolate sugars can be generated efficiently using Na2S. The subsequent addition reaction with Vinyl Compounds or organic halides has successfully been demonstrated, giving rise to the corresponding S-glycosides.
