Asymmetric Hydrogenation Catalyzed by the (Achiral Base)bis(dimethylglyoximato)cobalt(II)–Chiral Cocatalyst System. The Preparation of a New Type of Chiral Cocatalyst and Its Application to the Asymmetric Hydrogenation of MethylN-(Acetylamino)acrylate and Benzil
Nickel complexes from α-amino amides as efficient catalysts for the enantioselective Et2Zn addition to benzaldehyde
摘要:
Ni2+ complexes derived from simple alpha-amino amides catalyze very efficiently the addition of Et2Zn to benzaldehyde, giving (S)-1-phenylethanol as the major isomer in most cases (94% yield, 97% ee for R=Bn). The nature of the substituent on the amide nitrogen atom seems to play a key role in determining the asymmetric induction observed. (C) 2003 Elsevier Ltd. All rights reserved.
Superiority of the carbamoylmethyl ester as an acyl donor for the kinetically controlled amide-bond formation mediated by α-chymotrypsinElectronic supplementary information (ESI) available: elemental analyses and HPLC separation data. See http://www.rsc.org/suppdata/p1/b1/b108735p/
The superiority of the carbamoylmethyl ester as an acyl donor for the α-chymotrypsin-catalysed kinetically controlled peptide-bond formation is demonstrated in the couplings of an inherently poor amino acid substrate, Ala, with various amino acid residues as amino components and in the couplings of non-protein amino acids such as halogenophenylalanines as carboxylic components. Furthermore, this approach is applied to the amide-bond formation between an amino acid residue and a chiral amine, which is highly diastereoselective.
Kinetic regularities of resolution of amines racemates in the acylation reaction with chiral <i>N</i>‐protected amino acids esters
作者:Stanislav Bakhtin、Marina Sinelnikova
DOI:10.1002/kin.21681
日期:2023.11
establish the reaction orders with respect to the reagents, as well as the kinetic regularities of the enantioselective acylation. It is shown that different kinetic schemes of the reaction take place in protic and aprotic solvents. Based on the experimental data on the reaction kinetics of both the individual enantiomers and the amine racemate, the enantioselectivity values of the acylation are calculated