Enantioselective synthesis of 4-isoxazolines by 1,3-dipolar cycloadditions of nitrones to alkynals catalyzed by fluorodiphenylmethylpyrrolidines

Abstract

The first organocatalytic enantioselective 1,3-dipolar reaction between nitrones and alkynals catalyzed by (S)-2-(fluorodiphenylmethyl)pyrrolidine to give 4-isoxazolines (2,3-dihydroisoxazoles) with high enantiomeric excess, excellent yields and low catalyst loading (1-5 mol%) is presented. The catalytic loading could be reduced to 1 mol% with only slight increases in reaction times. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.