کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5267565 | 1385340 | 2011 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Entropy versus tether strain effects on rates of intramolecular 1,3-dipolar cycloadditions of N-alkenylnitrones
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Entropy versus tether strain effects on rates of intramolecular 1,3-dipolar cycloadditions of N-alkenylnitrones Entropy versus tether strain effects on rates of intramolecular 1,3-dipolar cycloadditions of N-alkenylnitrones](/preview/png/5267565.png)
چکیده انگلیسی
Intramolecular 1,3-dipolar cycloadditions of two N-alkenylnitrones are studied by means of density functional theory calculations. Cycloaddition of an acyclic 4-hexenylnitrone led to the expected isoxazolidine in 46% yield, but a 4-cycloheptenylnitrone did not react. Calculations of the transition states for cycloaddition indicate that although the cycloheptenyl nitrone has a more favorable activation entropy, the strain associated with distortion of the tethering groups into the required boat conformation disfavors the reaction of the cyclic substrate over the acyclic substrate by 8.7Â kcal/mol.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tetrahedron Letters - Volume 52, Issue 17, 27 April 2011, Pages 2181-2184
Journal: Tetrahedron Letters - Volume 52, Issue 17, 27 April 2011, Pages 2181-2184
نویسندگان
Elizabeth H. Krenske, K.N. Houk, Andrew B. Holmes, John Thompson,