A palladacycle phosphine mono-ylide complex was identified as an efficient catalyst system for the Mizoroki-Heck cross-coupling reactions of aromatic or aliphatic olefins with a variety of aryl bromides and chlorides, including those containing electron-donating or electron-withdrawing substituents. The reactions, which proceeded in moderate to excellent yields, required relatively low loadings of palladium (10 ppm) and were performed under aerobic conditions. High catalyst activities with turnover frequencies of up to 20,000 h -1 were observed at 130°C.The palladium-catalyzed arylation of olefins, known as the Heck cross-coupling reaction, is one of the most versatile tools for forming carbon-carbon bonds. 1-6 Tolerance to a wide spectrum of functional groups in both substrates makes this reaction very useful in total syntheses. Historically, palladium complexes with phosphine ligands have been widely used to catalyze these reactions. 7-10 The phosphine ligands act as stabilizers for catalytically active palladium(0) complexes that are generated in situ. Palladium complexes with bulky and strongly electrondonating trialkylphosphines are favored for carboncarbon coupling of aryl halides with styrene; 11,12 however, diphosphine ligands, because of their chelating effects, generally shows better coordination ability in stabilizing active palladium species in the catalytic cycle. Among the existing catalysts for these reactions, the most effective are homogeneous palladium-ligand systems. [13][14][15][16][17][18][19] The efficiency of a Heck reactions is greatly dependent on the reactivity of the palladacycle catalyst precursors. It is well established that palladacycle complexes containing phosphine ligands that combine both good donor strength and π-accepting capacity have high catalytic activities in Heck cross-coupling reactions. 20-22 Over the past ten years, we have studied phosphorus ylides and their palladium complexes, 23-28 and we have used some of these complexes in carbon-carbon coupling reactions. [29][30] Here, we describe the use of precatalyst 1 to promote the Mizoroki-Heck coupling reaction of aryl bromides or chlorides with olefins (Scheme 1). The reaction proceeds smoothly with deactivated aryl bromides or activated aryl chlorides and it gives good yields at low palladium loadings under aerobic conditions.The catalyst precursor 1 used for the Mizoroki-Heck cross-coupling reaction was prepared in high yield by reaction of 1-biphenyl-4-yl-2-[[(diphenylphosphino)-methyl](phenyl)phosphino]ethanone with dichloro(cyclooctadienyl)palladium in a 1:1 molar ratio at room temperature. 31The palladium-catalyzed Mizoroki-Heck reaction is among the most important carbon-carbon bond-forming processes for the vinylation of aryl or vinyl halides. As a result, considerable effort has been made to develop new and improved protocols for the Heck coupling reaction since the pivotal discovery of the reaction by Heck and Mizoroki in the early 1970s. [32][33][34][35] Many palladium phosphine complexes have been used as c...
Aim: The aim of this study was to determine the fit of the model of structural relationship between parent-adolescent conflict with emotional dysregulation, with the mediating role of loneliness in adolescents in Tehran. Methods: The statistical population of the study included adolescents aged 13 to 18 years in Tehran. Using available sampling method, 400 people (200 female adolescents and 200 male adolescents) were selected as the sample and used the Asadi and Younesi adolescent parent conflict questionnaire (1390), Russell (1996) revised feelings of loneliness, and Graz and Romer (2004) responded to emotional dysregulation. Structural equation model was used to analyze the data. Findings:The results showed that there was a positive and significant relationship between parent-adolescent conflict and emotion dysregulation (p<0.05). Also, there is a positive and significant relationship between parent-adolescent conflict with emotional dysregulation with the mediating role of loneliness (p<0.05). Conclusion: Based on research findings, it can be concluded that feeling lonely with the occurrence of emotions such as depression, anxiety, and fatigue can play a mediating role between parent-adolescent conflict and emotion disorder.
The title catalyst shows high catalytic activity in cross-coupling reactions of styrene and ethyl acrylate with aryl bromides and chlorides. The reactions proceed under aerobic conditions and require low loadings of the catalyst. -(SABOUNCHEI*, S. J.; AHMADI, M.; AZIZI, T.; PANAHIMEHR, M.; Synlett 25 (2014) 3, 336-342, http://dx.doi.org/10.1055/s-0033-1340319 ; Fac. Chem., Bu-Ali Sina Univ., Hamedan 65178, Iran; Eng.) -Mais 30-063
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