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51.
The first example of palladium-catalyzed stereoselective addition of diphenyl disulfide and diphenyl diselenide to the triple bond of terminal alkynes under microwave irradiation conditions is described. It was found that both the element—element (E-E) and carbon—element bonds can be activated in the catalytic system studied. The products of both reactions were isolated in quantitative yields. According to quantum-chemical calculations, the reaction mechanism involves the oxidative addition of the E-E bond to Pd0. Depending on the microwave power and reaction conditions, the next stage is either the reaction with alkyne or the carbon—element bond activation. The product of the oxidative addition of Ph2Se2 to Pd0, namely, dinuclear complex [Pd2(SePh)4(PPh3
2], was detected by 31P{1H}NMR spectroscopy directly in the Ph2Se2/PPh3 melt formed under microwave irradiation conditions.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 569–580, March, 2005. 相似文献
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Recent decades have been marked by enormous progress in the field of synthesis and chemistry of 5-(hydroxymethyl)furfural (HMF), an important platform chemical widely recognized as the “sleeping giant” of sustainable chemistry. This multifunctional furanic compound is viewed as a strong link for the transition from the current fossil-based industry to a sustainable one. However, the low chemical stability of HMF significantly undermines its synthetic potential. A possible solution to this problem is synthetic diversification of HMF by modifying it into more stable multifunctional building blocks for further synthetic purposes. 相似文献
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Valentine P. Ananikov Sergey S. Zalesskiy Vadim V. Kachala Irina P. Beletskaya 《Journal of organometallic chemistry》2011,696(1):400-405
In the present study we have analyzed the nature of palladium complexes in the catalytic system for selective carbon-sulfur bond formation via the addition of S-S and S-H bonds to alkynes. For the first time the mononuclear and dinuclear palladium complexes were clearly detected by DOSY NMR under the catalytic conditions. It was demonstrated that the concentration of these palladium complexes strongly depends on the amount of phosphine ligand available under reaction conditions. 相似文献
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Ananikov VP Gayduk KA Beletskaya IP Khrustalev VN Antipin MY 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(8):2420-2434
We have developed two new catalytic systems based on Ni and Pd complexes to solve the challenging problem of dialkyldichalcogenide (Alk2E2; E=S, Se) addition to alkynes. A comparative study of two catalytic systems-Ni/PMe2Ph and Pd/PCy2Ph-has revealed that the Ni catalyst is superior with respect to high catalytic activity and more general scope relative to the Pd system. A novel synthetic methodology was developed for the preparation of (Z)-bis(alkylthio)alkenes and (Z)-bis(alkylseleno)alkenes from terminal alkynes with excellent stereoselectivity and high yields. 相似文献
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Russian Chemical Bulletin - 相似文献
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Russian Chemical Bulletin - Magnetron sputtering was successfully used to obtain nanosized metal films and metal nanoparticles, which can be useful for development of novel methods in organic... 相似文献
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A new approach to determination of the stereochemical structure of bis-selenium-substituted alkenes using experimental 77Se NMR studies and B3LYP/6-311G(d) quantum-chemical calculations is developed. Joint analysis of experimental and calculated data allows assignment of signals in the 77Se NMR spectrum. The method was evaluated taking the model compounds (PhSe)HC=C(SePh)R (R = COOMe, CH2NMe2, CH2OH, Ph) as examples. 相似文献
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In hydrogen‐metal‐phosphorus (H M P) transition metal complexes (proposed as intermediates of H P bond addition to alkynes in the catalytic hydrophosphorylation, hydrophosphinylation, and hydrophospination reactions), alkyne insertion into the metal‐hydrogen bond was found much more facile compared to alkyne insertion into the metal‐phosphorus bond. The conclusion was verified for different metals (Pd, Ni, Pt, and Rh), ligands, and phosphorus groups at various theory levels (B3LYP, B3PW91, BLYP, MP2, and ONIOM). The relative reactivity of the metal complexes in the reaction with alkynes was estimated and decreased in the order of Ni>Pd>Rh>Pt. A trend in relative reactivity was established for various types of phosphorus groups: PR2>P(O)R2>P(O)(OR)2, which showed a decrease in rate upon increasing the number of the oxygen atoms attached to the phosphorus center. 相似文献