2-(aminomethyl)-oxazolines: highly modular scaffolds for the preparation of novel asymmetric ligands

Highly modular chiral 2-(aminoalkyl)oxazolines have been prepared from alpha-amino acids and 1,2-amino alcohols. The amine-functionalized oxazolines were employed as scaffolds in the preparation of a number of different ligands with potential denticities varying from 2 to 5. The obtained ligands were employed and evaluated in the ruthenium-catalyzed asymmetric transfer-hydrogenation of acetophenone and in the titanium-catalyzed addition of diethylzinc to aldehydes. In the latter process, enantioselectivity up to 97% was obtained.