کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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171175 | 458438 | 2010 | 7 صفحه PDF | دانلود رایگان |
Selective C-H bond activation of pyridines by organometallic complexes is a reaction of synthetic importance for the synthesis of functionalized pyridines. By reacting the dicationic methyl complex of yttrium [YMe(thf)6][BPh4]2 with substituted pyridines, both selectivity and kinetics have been studied. Electron donating properties of para-substituents of pyridines increase the rates of reaction. Hammett linear free energy relationship was found with ρ = –2.72. DFT calculations confirmed the two-step reaction consisting of ligand substitution followed by σ-bond metathesis. DFT calculations furthermore revealed for the C-H bond activation step an unusual transition state structure with a nearly linear methyl carbon-hydrogen-ortho-carbon arrangement.
Journal: Comptes Rendus Chimie - Volume 13, Issues 6–7, June–July 2010, Pages 626–632