Solid-Phase Synthesis of Chiral <i>N</i>-Acylethylenediamines and Their Use as Ligands for the Asymmetric Addition of Alkylzinc and Alkenylzinc Reagents to Aldehydes
作者:Christopher M. Sprout、Meaghan L. Richmond、Christopher T. Seto
DOI:10.1021/jo049160+
日期:2004.10.1
synthesis of chiral N-acylethylenediamine ligands. The ligands are obtained in good yield and purity, without the need for chromatography or other purification methods. Several new and previously reported ligands were prepared using this procedure. These compounds were examined as catalysts for the enantioselectiveaddition of alkylzincreagents to aldehydes. In all cases, the crude ligands from the solid-phase
Asymmetric syn-selective direct aldol reaction of protected hydroxyacetone catalyzed by primary amino acid derived bifunctional organocatalyst in the presence of water
derived from natural primary amino acids bearing a hydrophobic side chain have been synthesized. These new primary-tertiary diamine-Brønsted acid conjugates bifunctional organocatalysts efficiently catalyzes the asymmetric direct syn selective cross-aldolreaction of different protected hydroxyacetone with various aldehydes in high yield (94%) and high enantioselectivity (up to 97% ee of syn) and dr