Asymmetric Epoxidation of Unfunctionalized Olefins Using Novel Chiral Dihydroisoquinolinium Salts as Organocatalysts
作者:K. Ben Ali
DOI:10.1134/s1070428021040205
日期:2021.4
Abstract Two new non-racemic chiral dihydroisoquinolinium salts with N-substituents bulkier than a methyl group have been synthesized from (1S,2R)-norephedrine. These salts were used to catalyze asymmetricepoxidation of a series of prochiral olefins. One of the two new catalysts provided higher enantioselectivities (up to 66% ee) than the reference salt containing an N-methyl substituent.
A new chiral oxaziridinium salt has been prepared from (1S, 2R)-(+)-norephedrine. Enantioselective oxygen transfers to prochiral olefins and sulfides may be performed either stoichiometrically or in a catalytic cycle.
Organocatalysis of asymmetric epoxidation mediated by iminium salts: comments on the mechanism
作者:Philip C. Bulman Page、David Barros、Benjamin R. Buckley、Brian A. Marples
DOI:10.1016/j.tetasy.2005.08.053
日期:2005.10
Non-aqueous conditions developed for catalytic asymmetric epoxidation mediated by iminium salt organocatalysts have allowed NMR spectroscopy to be carried out on the reaction mixtures for the first time. (c) 2005 Elsevier Ltd. All rights reserved.