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Organocatalysts Promote Enantioselective 1,3‐Dipolar Cycloadditions of Nitrones with 1‐Cycloalkene‐1‐carboxaldehydes
Author(s) -
Karlsson Staffan,
Högberg HansErik
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300172
Subject(s) - chemistry , cycloalkene , enantiopure drug , diastereomer , enantioselective synthesis , organocatalysis , stereochemistry , organic chemistry , catalysis , medicinal chemistry
In the presence of enantiopure organocatalysts, 1‐cycloalkene‐1‐carboxaldehydes and various nitrones furnished fused isoxazolidines. Thus, some chiral pyrrolidinium salts catalyzed the formation of such cycloadducts in high diastereo‐ and enantioselectivity (up to 92% ee ). The predominant diastereomer, the exo one, was mostly obtained in excellent diastereoselectivity (> 99:1 dr ). Furthermore, after recrystallization of one of the cycloadducts, this was obtained enantiomerically pure (> 99% ee ). The absolute configuration of one of the cycloadducts was determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)