کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5280028 | 1385638 | 2005 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Scope and limitations of the catalytic asymmetric rearrangement of epoxides to allylic alcohols using chiral lithium amide bases/lithiated imidazoles
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
The catalytic asymmetric rearrangement of functionalised cyclohexene and cyclopentene oxides has been studied using sub-stoichiometric amounts of a chiral lithium amide in combination with a stoichiometric amount of three different lithiated imidazoles. 1-Methylimidazole that had been lithiated at the C-2 aryl position gave the highest enantioselectivity (82% ee). With 1,2-dimethylimidazole that had been lithiated at the C-2 methyl group, epoxide ring opening occurred as an unexpected and competing process. Ultimately, ring opening was suppressed using a more sterically hindered imidazole. In all catalytic examples, a racemic background reaction (presumably due to rearrangement by the lithiated imidazoles) was observed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tetrahedron Letters - Volume 46, Issue 48, 28 November 2005, Pages 8315-8318
Journal: Tetrahedron Letters - Volume 46, Issue 48, 28 November 2005, Pages 8315-8318
نویسندگان
Sally J. Oxenford, Jonathan M. Wright, Peter O'Brien, Narendra Panday, Mark R. Shipton,