کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
42784 45941 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Imines derived from (1S,2R)-norephedrine as catalysts in the enantioselective addition of diethylzinc to aldehydes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Imines derived from (1S,2R)-norephedrine as catalysts in the enantioselective addition of diethylzinc to aldehydes
چکیده انگلیسی

Purpose of the research was to determine the activity of chiral imine ligands prepared from (1S,2R)-norephedrine for the enantioselective addition of diethylzinc to aldehydes. Imine ligands reveal medium enantioselectivity, with the ee exceeding 30%. The highest ee (97%) was obtained for imine with 9-anthryl substituent, when p-methoxybenzaldehyde was used as substrate. The yields of the reaction obtained after 24–72 h reached 76–96%. The absolute configuration of the addition product depends on the geometry of presented transition states and π–π stacking interactions between the investigated ligands and the benzaldehyde substrate. Imine ligands derived 2-hydroxyacetophenone and with 9-anthryl substituent reveal strong absorbance in UV–vis spectra. Intermediates for the imines – diethylzinc – based catalysis and probable mechanisms were proposed.

A series of chiral imine ligands was prepared from (1S,2R)-norephedrine and applied for the enantioselective addition of diethylzinc to aldehydes. The absolute configuration of the addition product depends on the imine's nitrogen substituent. The highest ee (97%) was observed for imine with 9-anthryl substituent, when applied for p-methoxybenzaldehyde as substrate. Imine ligands derived 2-hydroxyacetophenone and with 9-anthryl substituent reveal strong absorbance in UV–vis spectra. Intermediates for the imines – diethylzinc – based catalysis and probable mechanisms were proposed.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Catalysis A: General - Volume 357, Issue 2, 15 April 2009, Pages 150–158
نویسندگان
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