An investigation of the impact of oxygenated side chains in Ephedra compounds on the catalytic asymmetric addition of diethylzinc to aldehydes has been conducted.(1R, 2S)- Ephedrine and (1S, 2S)-pseudoephedrine were alkylated with either alkyl halides or β- alkoxyalkyl halides to afford a series of ligands 9a–h and 10a–h. These compounds were employed in the enantioselective addition of diethylzinc to a variety of aldehydes. It was ...