Double Stereodifferentiation in the Catalytic Asymmetric Aziridination of Imines Prepared from α-Chiral Amines
作者:Li Huang、Yu Zhang、Richard J. Staples、Rui H. Huang、William D. Wulff
DOI:10.1002/chem.201102520
日期:2012.4.23
The catalyticasymmetricaziridination of imines and diazo compounds (AZ reaction) mediated by boroxinate catalysts derived from the VANOL and VAPOL ligands was investigated with chiral imines derived from five different chiral, disubstituted, methyl amines. The strongest matched and mismatched reactions with the two enantiomers of the catalyst were noted with disubstituted methyl amines that had one
Chiral oxaziridines in the enantioselective synthesis of isoxazolidines
作者:Luigino Troisi、Sara De Lorenzis、Marilena Fabio、Francesca Rosato、Catia Granito
DOI:10.1016/j.tetasy.2008.09.016
日期:2008.10
The stereoselective synthesis of oxaziridines with three stereogenic centres is presented in this paper. The chirality is provided by asymmetric induction, and a possible mechanism for the induced stereoselectivity is also discussed. These small heterocycles undergo the [3+2] cycloaddition reaction with aryl ethenes to afford enantiomerically pure isoxazolidines of controlled configurations. This class
Diastereoselective Synthesis of Secondary Propargylamines Exploiting CuI-Based Promoters and Determination of Their Relative Configuration by DFT-GIAO Conformational Analysis
promoting systems. The reported methodologies were compared in terms of efficiency, diastereoselectivity, and toxicity, both showing advantages with respect to the current methodologies. The relative configurations of each of the obtained propargylamines, previously unknown in the literature, were assigned by comparison of the 1H NMR experimental chemical shifts with those theoretically predicted via the
Asymmetric induction in the addition of enantiomerically pure H -phosphinate to chiral aldimines: diastereoselective generation of α-amino phosphinates with P , C -stereogenic centers
alpha-Amino phosphinates with P,C-stereogenic centers were prepared from a P-retained addition of (R-p)-(-)-menthyl H-phenylphosphinate to (R)-aldimines with up to 86:14 dr under catalyst and solvent free condition at ambient temperature; the single (S-p,S alpha-c)-stereoisomers were isolated in moderate yields. Chirality on the nitrogen of chiral aldimine was proposed to control the stereoselectivity, and the (-)-menthoxyl showed mismatched asymmetric induction with (S)-aldimines. (C) 2016 Elsevier Ltd. All rights reserved.