Synthesis of poly[N-(4-ethynylbenzyl)ephedrine] and its use as a polymeric catalyst for enantioselective addition of dialkylzincs to benzaldehyde

Abstract

A novel, optically active, cis-transoidal polyacetylene, poly[N-(4-ethynylbenzyl)ephedrine] (poly-4b) was prepared and interactions with chiral acids were examined by means of circular dichroism (CD) spectroscopy. The intensity of induced CD of the polymer decreased with an increase in the concentration of (R)- or (S)-mandelic acid. However, significant differences between the induced CD changes in the presence of (R)- or (S)-mandelic acid were not found in the complexation. Poly-4b was used as an optically active catalyst for enantioselective addition of benzaldehyde with dialkylzincs. Enantiomeric excess of 1-phenylethanol obtained was 30-49%.