کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5218533 | 1383330 | 2012 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Enantioenriched Ï-bromocyanohydrin derivatives. Improved selectivity by combination of two chiral catalysts
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Highly enantioenriched (R)-4-bromo-1-cyanobutyl acetate and (R)-5-bromo-1-cyanopentyl acetate were prepared by acetylcyanation of 4-bromobutanal and 5-bromopentanal, respectively, catalyzed by (S,S)-[(4,6-bis(t-butyl)salen)Ti(μ-O)]2 and triethylamine followed by enzymatic hydrolysis of the minor enantiomer. A cyclic procedure employing the same two chiral catalysts provided inferior results due to a slowly reached steady state and, in reactions with the former substrate, to ring-closure of the free cyanohydrin formed as an intermediate in the reaction. Hydrolysis of the acylated cyanohydrins followed by AgClO4-promoted cyclization provided (R)-2-cyanotetrahydrofuran and (R)-2-cyanotetrahydropyran in essentially enantiopure form.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tetrahedron - Volume 68, Issue 37, 16 September 2012, Pages 7680-7684
Journal: Tetrahedron - Volume 68, Issue 37, 16 September 2012, Pages 7680-7684
نویسندگان
Robin Hertzberg, Khalid Widyan, Berenice Heid, Christina Moberg,