- Extended Pummerer fragmentation mediated by carbon dioxide and cyanide
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Pummerer rearrangement reactions generate sulfur (II) oxidation state from sulfur (IV) starting materials in the presence of activating reagents. We found unprecedented transformation of vinyl sulfoxide; disulfide formation reactions mediated by atmospheric pressure of carbon dioxide in extended Pummerer rearrangement reactions. Only under CO2 atmosphere, we observed moderate to high yields of disulfide starting from sulfur (IV) starting materials. Investigations on the reaction mechanism revealed that the degradation of the starting materials and the products was significant in the absence of CO2. Further evidence for the suggested reaction mechanism was obtained by a cross-over experiment and a radical trapping reagent.
- Liu, Jian,Kragh, Rasmus R.,Kamounah, Fadhil S.,Lee, Ji-Woong
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supporting information
(2020/10/30)
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- Safe and Metal-Free Synthesis of 1-Alkenyl Aryl Sulfides and Their Sulfones from Thiiranes and Diaryliodonium Salts
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A series of 1-alkenyl aryl sulfides was synthesized from thiiranes and diaryliodonium salts in tetrahydrofuran in the presence of potassium tert -butoxide. The proposed reaction mechanism involves generation of benzynes from the diaryliodonium salts in the presence of the base. Then, nucleophilic attack of the benzynes by thiiranes, followed by hydrogen abstraction and ring opening of the generated thiiranium intermediates, provides the sulfides. These sulfides were further oxidized with performic acid to the corresponding sulfones. The current method provides a metal-free and safe method for the preparation of 1-alkenyl aryl sulfides and their sulfones.
- Dong, Jun,Xu, Jiaxi
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p. 2407 - 2415
(2018/04/16)
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- RAFT polymerization of s -vinyl sulfide derivatives and synthesis of block copolymers having two distinct optoelectronic functionalities
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Well-defined sulfur-containing polymers and block copolymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of S-vinyl sulfide derivatives, in which the thioether moiety is directly connected to the vinyl group. We initially investigated RAFT polymerization of four different S-vinyl sulfide derivatives, phenyl vinyl sulfide (PVS), 4-chlorophenyl vinyl sulfide (CPVS), 2,4-dichlorophenyl vinyl sulfide (DCPVS), and 4-bromophenyl vinyl sulfide (BPVS). Three xanthate-type chain transfer agents (CTAs), a dithiocarbamate-type CTA, and a dithioester-type CTA were compared for these RAFT polymerizations. Reasonable control of the polymerization of PVS was confirmed by an observed linear increase in the molecular weight with the conversion, feasibility to control molecular weight based on the ratio of monomer consumed to the amount of CTA used, chain end structure determined by 1H NMR, and chain extension experiment. The RAFT polymerization of the bromo-substituted monomer (BPVS) also proceeded in the controlled fashion under the same conditions. Incorporation of optoelectronic groups, including anthracene, fluorene, diphenylamine, and phenothiazine on the bromophenyl pendant group of poly(BPVS) were accomplished by palladium-catalyzed postmodifications. We also investigated characteristic optoelectronic properties of modified polymers and block copolymers with two distinct electronic functionalities.
- Nakabayashi, Kazuhiro,Abiko, Yohei,Mori, Hideharu
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p. 5998 - 6012
(2013/09/02)
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- Pyrolysis of α- and β-heteroatoms substituted ethyl phenyl sulfoxides
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A study on the mechanism of the thermal decomposition of α- and β-heteroatoms substituted ethyl phenyl sulfoxides was carried out using 1-chloroethyl phenyl sulfoxide (1); two diastereomeric 1-acetoxyethyl (substituted phenyl) sulfoxides (2a) and (2b); and 2-chloroethyl phenyl, 2-bromoethyl phenyl, and 2-methoxyethyl phenyl sulfoxides (3, 4, 5). The rate of pyrolysis of 1 was 4.8 times faster at 160°C than that of ethyl phenyl sulfoxide used as a reference, while those of 2a and 2b were 107 and 155 times faster, respectively. The results indicate that the lone pair of electrons on the α-heteroatoms has a larger rate acceleration effect than the electronegativity of them. The substituent effects of the phenyl group of 2a and 2b gave positive Hammett ρ-values (ρa= 0.76 and ρb= 0.80 vs. σ). Activation parameters for 2a and 2b are as follows: 2a, ΔH?= 112 kJmol-1, ΔS?= -20 JK-1mol-1; 2b, ΔH?= 107 kJmol-1, ΔS?= -29 JK-1mol-1. Large deuterium kinetic isotope effects for 1-acetoxyethyl-2,2,2-d3 phenyl sulfoxides (2ad and 2bd) were observed (kH/kD= 3.5 ~ 4.1). These results suggest that the pyrolysis of -heteroatom substituted ethyl phenyl sulfoxides proceeds via a five-membered transition state deviated to E1-like in character. On the other hand, from the results of kinetics for the pyrolysis of 3, 4, and 5, no effect by the β-halogen atoms or some deceleration effect by the β-methoxy group was observed. Thus the reaction seems to proceed via an E1-like mechanism. Copyright Taylor & Francis Group.
- Yoshimura, Toshiaki,Sakae, Hironori,Yoshizawa, Masaki,Hasegawa, Kiyoshi,Tsukurimichi, Eiichi
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experimental part
p. 1162 - 1173
(2010/08/06)
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- Ring-opening metathesis polymerization using alkenyl sulfides as chain-transfer agents: Efficient route to unsymmetrical poly(norbornene)-based macroinitiators bearing a terminal hydroxy group
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Convenient routes to hydroxy-terminated poly(norbornene)s (PNBEs) have been developed. Hydroboration of PNBEs bearing a terminal vinyl group with 9-BBN followed by oxidation with H2O2/ NaOH forms of hydroxy-terminated PNBEs in high yields. The parent PNBEs are prepared by ring-opening metathesis polymerization (ROMP) of norbornene using vinylic sulfides as chain-transfer agents (CTAs). On the other hand, ROMP of norbornene using (Z)-1-phenylthio-1-propen-3-ol as a CTA causes one-step synthesis of ω-hydroxy-terminated PNBE, where the molecular weight of polymer depends linearly on the initial feed ratio of CTA to monomer. Similarly, ROMP reactions using (Z)-1-phenylthio-1-propen-3-ols having bromo, amino, and 4-(chloromethyl)benzamido substituents at the para position of the phenyl group as CTAs afford the corresponding α,ω-heterodifunctionalized (heterotelechelic) PNBEs. The resulting PNBEs serve as macroinitiators for anionic ring-opening polymerization (AROP) of εcaprolactone and atom-transfer radical polymerization (ATRP) of styrene, giving AB- and ABC-type block copolymers.
- Katayama, Hiroyuki,Fukuse, Yosuke,Nobuto, Yuko,Akamatsu, Kensuke,Ozawa, Fumiyuki
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p. 7020 - 7026
(2007/10/03)
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- Flash Vacuum Pyrolysis of Alkoxycarbonyl/Sulfinyl Stabilised Phosphorus Ylides: Generation and Intramolecular Insertion of Alkoxycarbonyl(sulfenyl)carbenes
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Flash vacuum pyrolysis of phosphorus ylides stabilised both by ester and sulfinyl groups results mainly in extrusion of Ph3PO to generate alkoxycarbonyl(sulfenyl)carbenes; these undergo intramolecular insertion into CH of the alkoxycarbonyl group giving β-lactones which under the conditions lose CO2 to afford alkenyl sulfides.
- Aitken, R. Alan,Drysdale, Martin J.,Ryan, Bruce M.
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p. 805 - 806
(2007/10/02)
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- Competing Hole catalyzed Diels-Alder and cyclobutanation/vinylcyclobutane rearrangement paths. A mechanistic dichotomy
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Kinetic studies of the tris(4-bromophenyl)aminium hexachloroantimonate catalyzed cycloaddition of phenyl vinyl sulfide (1) and 1,1′-bicyclopentenyl (2) reveal three discernible stages: (1) a cycloaddition stage in which cyclobutanation predominates over D
- Kim, Taisun,Jerome Pye,Bauld, Nathan L.
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p. 6285 - 6290
(2007/10/02)
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