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A competitive Diels-Alder/1, 3-dipolar cycloaddition reaction of1-H-imidazole 3-oxide toward sulfonyl methane. A DFT study on the energetic and regioselectivity | ||
Journal of Physical & Theoretical Chemistry | ||
مقاله 7، دوره 12، شماره 4، خرداد 2016، صفحه 339-348 اصل مقاله (561.25 K) | ||
نوع مقاله: Research Paper | ||
نویسنده | ||
Saeedreza Emamian | ||
Chemistry Department, Shahrood Branch, Islamic Azad University, Shahrood, Iran | ||
چکیده | ||
The dual diene/1,3-dipolar character of 1-H-imidazole 3-oxide, HIO 1, allows this compound to participate in a competitive Diels-Alder (DA)/1,3-dipolar cycloaddition (13DC) reaction toward C=S double bond of the electro-deficient sulfonyl methane SFM 2. The B3LYP/6-311++G(d,p) calculated relative Gibbs free energies indicate that among the studied 13DC and DA reactions, former is completely preferred over the latter in the gas phase as well as in the presence of dichloromethane (DCM). This 13DC reaction takes place through a one-step mechanism to generate corresponding five-membered cycloadduct via a quite C1-S5 regioselective fashion which is controlled by theHOMO(HIO 1)- LUMO(SFM 2) interaction.The aromatic character of HIO 1 which is lost along the studied cycloaddition reaction is responsible for the relatively high activation Gibbs free energies and the endergonic character of these thermodynamically reversible reactions. The quite C1-S5 regioselectivity, resulted from energetic studies, in the investigated 13DC reactioncan be explained usingcalculated electrophilic and nucleophilic Parr functions at the reactive sites of reagents. | ||
کلیدواژهها | ||
Diels-Alder and 1, 3-dipolar cycloaddition reactions؛ Regioselectivity؛ DFT reactivity indices؛ FMOs interaction؛ Parr functions | ||
آمار تعداد مشاهده مقاله: 786 تعداد دریافت فایل اصل مقاله: 420 |