Synthesis of enantiopure 2-aminoalkylphenols by stereoselective addition of Grignard reagents to chiral 2-imidoylphenols

Abstract

The stereoselective addition of Grignard reagents to chiral 2-imidoylphenols affords enantiopure 2-aminoalkylphenols, a class of ligands useful in stereoselective synthesis. Unusually benzyl- and allyl-magnesium chlorides add to ketimines derived from enolizable o-acylphenols with high yields and stereoselectivities. In this way a stereogenic quaternary C-1 carbon atom is introduced, which could not be obtained by other methods available till now. The mechanism and the asymmetric induction have been explained in agreement with previously obtained results.