[EN] ENANTIONSELECTIVE PROCESSES TO INSECTICIDAL 3-ARYL-3-TRIFLUOROMETHYL-SUBSTITUTED PYRROLIDINES [FR] PROCÉDÉS ÉNANTIOSÉLECTIFS POUR DES INSECTICIDES DE PYRROLIDINES 3-ARYL-3-TRIFLUOROMÉTHYL-SUBSTITUÉES
A new class of asymmetric phase-transfer catalysts derived from Cinchona alkaloids — Application in the enantioselective synthesis of α-amino acids
作者:Barry Lygo、Philip G. Wainwright
DOI:10.1016/s0040-4039(97)10293-3
日期:1997.12
new class of Cinchona alkaloid-derived quaternary ammonium phase-transfercatalysts bearing a N-anthracenylmethyl function are presented. These catalysts show high stereocontrol in the asymmetric alkylation of a benzophenone-derived glycine-imine, and application of this process to the enantioselectivesynthesis of a range of α-aminoacid esters (e.e. 67–94%) is investigated.
A general catalytic enantioselective trifluoromethylation of aromatic aldehydes using (IPr)CuF and quinidine-derived quaternary ammonium salt as catalysts has been developed. A wide range of aromatic aldehydes are converted to the corresponding products in up to 92% yield and 81% ee at 2 mol% of catalyst loading. (C) 2013 Elsevier B.V. All rights reserved.
Catalytic asymmetric epoxidation of enones under phase-transfer catalyzed conditions
The development of the catalytic asymmetric epoxidation of enones promoted by aqueous H2O2 with chiral quaternary ammonium salts is described. The reaction smoothly proceeded to give alpha,beta-epoxyketones with satisfactory enantioselectivities in both the trans and cis enone systems (up to 92% ee) by use of cinchonine or quinidine derivatives (5 mol%) as phase transfer catalysts. (C) 2002 Elsevier Science Ltd. All tights reserved.