جستجوی مقالات مرتبط با کلیدواژه « alkenes » در نشریات گروه « شیمی »

The aim of the present review is to summarize the recent advances in the synthesis of β-hydroxy selenides through the direct hydroxyselenenylation of alkenes in the past 45 years. Hopefully, it can provide practical guidance for the readers who are interested in the application of difunctionalization reactions in the synthesis of functionalizaed organoselenium compounds. For simplicity and clarity, the organization of this review is based on the type of catalysts.

The aim of this review is to summarize the available literature on the direct hydroxyazidation of alkenes, with particular emphasize on the mechanistic features of the reactions. The metal-catalyzed reactions are discussed first. This is followed by iodine- and enzyme-catalyzed reactions. Finally, the available examples on light-mediated reactions will be covered at the end of this review.

The direct fluorinative difunctionalization of alkenes is one of the most convenient platforms to the structurally complex organofluorine compounds from bulk chemicals. Accordingly, tremendous efforts to explore synthetic methodologies in this research area have been documented. In this family of reactions, the direct hydroxyfluorination of simple alkenes has emerged as a sustainable and powerful synthetic strategy for the efficient construction of vicinal fluorohydrins, which are found widespread applications in the fields of human life. The purpose of this review is to provide an overview of the available evidence on the synthesis of vicinal fluorohydrins through the direct hydroxyfluorination of corresponding alkenes. Literature has been surveyed from 1999 to the end of October 2023.

Quantitative structure–property relationship (QSPR) models establish relationships between different types of structural information to their properties. In the present study the relationship between the molecular descriptors and quantum properties consist of the heat capacity (Cv/J mol-1K-1) entropy (S/J mol-1K-1) and thermal energy (Eth/kJ mol-1) of 100 alkenes is represented. Genetic algorithm (GA) and backward-multiple linear regressions (BW-MLR) were successfully developed to predict quantum properties of alkenes. Molecular descriptors were calculated with Dragon software and the genetic algorithm (GA) method was used to selected important molecular descriptors. The quantum properties were obtained from quantum-chemistry technique at the Hartree-Fock (HF) level using the ab initio 6-31G* basis sets. The predictive powers of the BW-MLR models were discussed by using leave-one-out (LOO) cross-validation and external test set. Results showed that the predictive ability of the models was satisfactory, and the 2D matrix-based descriptors, topological, edge adjacency and Connectivity indices could be used to predict the mentioned properties of 100 alkenes

This work was conducted to evaluate catalytic efficiency of red clay of Adrar-Algeria zone as an effective green catalyst on the Aza Michael reaction. The Aza-Michael reaction is the addition of amine to α, β-unsaturated alkene was carried out using raw red clay from the Adrar-Algeria area as a catalyst to synthesize the new carbon-carbon or carbon-heteroatom bond containing products. The reaction was carried out with favorable conditions, ambient temperature, without solvent, and the protocol likes the environment, so-that the synthesized products provide high yields and excellent chemo selectivity.

Polyphosphotungstate (denoted as PPT) was supported on polypyrrol as organic support (abbreviated as PTT@Ppy) to produce catalytic active supported catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The catalyst showed high catalytic activity in the oxidation of alkenes under optimized conditions. In this work, cyclooctene was selected as model alkene for investigation of oxidation procedure, and then under optimized condition, other alkenes were examined. The catalyst could be readily separated from the catalytic system using the centrifuging and loss of activity was negligible when the catalyst was recovered in five consecutive cycles. For this research, a statistical method called response surface methodology (RSM) has been used to economize the number of experiments and their meaningful interpretation. The effect of various factors such as catalyst amount, time, oxidant amount and temperature on oxidation of alkenes were investigated. Optimization results for 0.2 mmol cyclooctene showed that maximum oxidation efficiency 88% was achieved at the optimum conditions: catalyst amount 200 mg, temperature 63, time 5 h and oxidant = 2.15 mmol.

The complexes between C20 and C2X4, C2X2 (X = H, F, Cl, Br) have been studied theoretically at the B3LYP/6-311G (d,p) level. The calculations include the optimized geometries, the interaction energies, aromaticity and thermodynamic. The interaction energies ranging from -60 to -101 kcal/mol and being ordered as: X = F> Cl > Br. Natural bond orbital (NBO) analysis has been performed on all geometries. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results, and indicate that, in all the molecules HOMO-1 → LUMO transition has the major contribution in the most intensity electronic transition.