189309-24-8Relevant articles and documents
Highly efficient asymmetric additions of diethylzinc to aldehydes triply activated by chiral phosphoramide-Zn(II) complexes derived from cinchona alkaloids
Shen, Bin,Huang, Huayin,Bian, Guangling,Zong, Hua,Song, Ling
, p. 561 - 566 (2013/09/12)
New chiral phosphoramide ligands derived from cinchona alkaloids were developed, which react with diethylzinc to form chiral phosphoramide-Zn(II) complexes containing two Lewis bases and one Lewis acid. These trifunctional complexes can serve as highly efficient chiral catalysts for triple activation of enantioselective addition reactions of diethylzinc with aldehydes to give desired alcohol products with excellent yields and enantiomeric excess (ee) values up to 99%. 2013 Wiley Periodicals, Inc.
Enantioselektive Katalyse, 106 9-Amino(9-deoxy)cinchona-Alkaloide und Deren Derivate
Brunner, H.,Buegler, J.
, p. 77 - 84 (2007/10/03)
The stereospecific formation of 9-amino(9-deoxy)cinchona alkaloids with the configuration of the corresponding natural products was achieved by a sequence of reactions, including a substitution with inversion of configuration. Thus, the corresponding epi-alkaloids were reacted with hydrazoic acid, triphenylphosphine and diisopropyl azodicarboxylate followed by an in situ reduction of the intermediary azides. The configurations of the products were established by CD- and 1H-NMR-spectroscopy. Several amide, imine and amine derivatives were prepared from these amino-substituted alkaloids. Their ability to induce enantiomeric excess in asymmetric syntheses was tested.
