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111.
Chen-Yang Tsai Yin-Jia Jhang Yen-Ku Wu Prof. Ilhyong Ryu 《Angewandte Chemie (International ed. in English)》2023,62(49):e202311807
We report a protocol for alkene hydroxyalkenylation. Using a persulfate anion as a one-electron-oxidation reagent and 1,2-bis(phenylsulfonyl)ethylene as a radical acceptor in the presence of water, alkenes were converted into the corresponding 1-phenylsulfonyl-4-hydroxyalkenes in good to high yields. The hydroxyalkenylation process involves the nucleophilic hydroxylation of alkene radical cations to give β-hydroxyalkyl radicals, which, after a radical addition/β-elimination sequence, provide the products. We also report a photocatalytic protocol for alkoxyalkenylation. 相似文献
112.
Organozinc reagents (organozinc halides, diorganozincs and mixed copper-zinc reagents) react with β-(allyloxy)-enoates via a radical-polar crossover process to afford substituted furans in one single synthetic step following a domino reaction involving Michael addition and carbocyclisation. Reversal of diastereoselectivity can be obtained varying the organometallic and/or the reaction conditions. 相似文献
113.
M. Nsangou Z. Dhaouadi N. Jaidane Z. Ben Lakhdar 《Journal of Molecular Structure》2008,850(1-3):135-143
B3LYP/6-31++G(d) method was used for the structural study of 3,4,5-trihydroxybenzoic acid (3,4,5-THBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), and 4-hydroxybenzoic acid (4-HBA). Calculated structures agree with available X-ray experimental data within 2%. The phenolic OH bond dissociation enthalpy (BDE) of all sites in each benzoic acid were determined and compared with those of phenol (for 4-HBA) and catechol (for 3,4-DHBA). The consistency between the calculated values and experimental ones are within 5.4% and 9.2%, respectively, for 4-HBA and 3,4-DHBA. The reactions of benzoic acids with and OH radicals were studied and it turns out that benzoic acids react differently with both radicals. We have shown that the reaction of hydroxybenzoic acids with the hydroxyl radical was governed by a phenolic hydrogen (H+ + e−) transfer from the acid to the radical, while for the superoxide radical, the reaction is governed by a proton (H+) transfer from the acid to the radical. The first reaction is evidenced by the delocalization of the radical on the entire quinone moiety, and the second reaction is evidenced by the negative NBO charge on the phenoxide moiety as well as the localization of the radical on the hydroperoxy (O2H) moiety. 相似文献
114.
Over the last two decades, the scientific community and industry have made huge efforts to develop environmental protection technologies. In particular, the scarcity of drinking water has prompted the investigation of several physico-chemical treatments, and synergistic effects have been observed in hyphenated techniques. Herein, we report the first example of water treatment under simultaneous hydrodynamic cavitation and plasma discharge with the intense generation of radicals, UV light, shock waves and charged particles. This highly reactive environment is well suited to the bulk treatment of polluted water (i.e. E. coli disinfection and organic pollutant degradation). We have developed a new prototype and have efficiently applied this hybrid technology to water disinfection and the complete degradation of methanol in water with the aim of demonstrating its scalability. We have analyzed the mechanisms of water disinfection under the abovementioned conditions and verified them by measuring cavitation noise spectra and plasma emission spectra. We have also used the degradation of textile dyes and methanol solutions as an indicator for the formation of radicals. 相似文献
115.
Ling-Li Cheng Mei Wang Hui Zhu Kun Li Rong-Rong Zhu Xiao-Yu Sun Si-De Yao Qing-Sheng Wu Shi-Long Wang 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,73(5):955-959
Using 266 nm laser flash photolysis it has been demonstrated that Berberine (BBR) in aqueous solution is ionized via a mono-photonic process giving a hydrated electron, anion radical that formed by hydrated electron react with steady state of BBR, and neutral radical that formed from rapid deprotonation of the radical cation of BBR. The quantum yield of photoionization is determined to be 0.03 at room temperature with KI solution used as a reference. Furthermore utilizing pH changing method and the SO4− radical oxidation method, the assignment of radical cation of BBR was further confirmed, the pKa value of it was calculated, and the related set up rate constant was also determined. 相似文献
116.
117.
Philip P. Power 《Journal of organometallic chemistry》2004,689(24):3904-3919
The development of bulky monodentate alkoxide, chalcogenolate (ER, E = S, Se or Te), amide, pnictide (ER2 = N, P, As), alkyl, aryl and silyl ligands is briefly surveyed. These ligands have played a key role in the advancement of the modern organometallic and inorganic chemistry of all the major blocks (s, p, d, and f) of the periodic table. Most importantly, they have permitted numerous new classes of compounds to be isolated and studied. The investigation of steric effects induced by these ligands has led to, inter alia, transition metal alkylidene and alkylidyne complexes, room temperature cleavage of dinitrogen, and a wide range of transition metal and lanthanide complexes with two or three coordination. In addition, their use has sparked a revolution in main group chemistry which has led to the isolation of stable species with bonds and/or oxidation states hitherto unknown in stable compounds. 相似文献
118.
Alicia Boto Rosendo Hernández Adriana Montoya Ernesto Suárez 《Tetrahedron letters》2004,45(7):1559-1563
The fragmentation of primary alkoxyl radicals, often described as low yielding and plagued by side reactions, proceeded in good to excellent yields when aminol derivatives were used as substrates. Remarkably, no side reactions such as hydrogen abstraction or oxidation were observed. The fragmentation can be coupled with an alkylation reaction to give 2-substituted pyrrolidine and piperidine rings such as alkaloid analogues and functionalized, chiral nitrogen heterocycles. 相似文献
119.
Benzobicyclic δ-oxo-α,β-unsaturated esters easily prepared from tetralones or benzosuberone, readily cyclise in the presence of samarium diiodide and tert-butanol according to a totally syn mode, leading selectively to ‘cis’ ring-fused cyclopropanols that spontaneously lactonise to tetracyclic compounds. 相似文献
120.
Ikuo Shinohara 《Tetrahedron letters》2004,45(7):1495-1498
Novel ring-expansion reaction of 1,2-cyclobutanedicarboxylates with Sm(II) in the presence of HMPA with a catalytic amount of methanol was found to provide 2-oxocyclopentanecarboxylates. 相似文献