کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1315771 976069 2006 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Application of axially dissymmetric ligand recoverable with fluorous solvent as a chiral auxiliary
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Application of axially dissymmetric ligand recoverable with fluorous solvent as a chiral auxiliary
چکیده انگلیسی

(Ra)-(R)2-2,2′-Bis(1-hydroxy-1H-perfluorooctyl)biphenyl ((Ra)-(R)2-1c), which is an axially dissymmetric ligand with two chiral centers, works as a good chiral auxiliary for asymmetric aldol reaction. Thus, the reaction of monopropanoyl ester of 1c (2) with benzaldehyde in the presence of triethylamine and titanium(IV) chloride gave (2R),(3S)- and (2R),(3R)-3-hydroxy-2-methyl-3-phenylpropanoic acid esters (3a) in an approximate ratio of 4:1 in a total high yield. This result shows that stereoselectivity at 2-position is quite high, while that at 3-position is moderate. Both isomers were easily separated by column chromatography. Methanolysis of the separated isomers gave nearly quantitative recovery of 1c by extraction with a fluorous solvent without any loss of ee, while methyl (2R),(3S)- or (2R),(3R)-3-hydroxy-2-methyl-3-phenylpropanoates were obtained by CH2Cl2 extraction quantitatively in >99% ee. Aldol reaction of 2 with various aldehydes gave similar results.

Axially dissymmetric ligand works as a good chiral auxiliary for asymmetric aldol reaction. Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Fluorine Chemistry - Volume 127, Issue 1, January 2006, Pages 74–78
نویسندگان
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