Bis(ethylsulfonamide)amines via nucleophilic ring-opening of chiral aziridines. Application to Ti-mediated addition of diethylzinc to benzaldehyde
摘要:
Homochiral bis(N-triflyl-2-alkyl-2-aminoethyl)amines obtained from N-triflyl-2-alkylaziridines via reaction with benzylamine, catalyze the titanium-mediated addition of diethylzinc to benzaldehyde to yield 1-phenylpropanol in up to 78% ee in the presence of molecular sieves. Use of tetradentate analogs prepared by reaction of the aziridine with 2-(aminomethyl)pyridine or 2-aminophenol resulted in lower enantioselectivity. (C) 1997 Elsevier Science Ltd.
Highly Practical and Enantioselective Cu-Catalyzed Conjugate Addition of Alkylzinc Reagents to Cyclic Enones at Ambient Temperature
作者:Isaac J. Krauss、James L. Leighton
DOI:10.1021/ol034983r
日期:2003.9.1
[GRAPHICS]A new ligand for Cu-catalyzed enantioselective additions of dialkylzincs to cyclic enones has been developed. In addition to providing good to excellent enantioselectivities with a range of cyclic enones and dialkylzincs, the ligand has several notworthy features: it can be readily prepared in just two steps, is an air-stable crystalline solid, and provides optimal performance at ambient temperature.