Synthesis and enantioselectivities of soluble polymers incorporating optically active binaphthyl and binaphthol

Abstract

Abstract A polymer ( P‐1 ) was synthesized through the polymerization of ( S )‐6,6′‐dibromo‐3,3′‐dibutyl‐1,1′‐binaphthol with ( S )‐2,2′‐dioctoxy‐1,1′‐binaphthyl‐6,6′‐boronic acid in a Pd‐catalyzed Suzuki reaction, and another polymer ( P‐2 ) was synthesized through the polymerization of ( S )‐6,6′‐dibromo‐3,3′‐dibutyl‐1,1′‐binaphthol with ( S )‐6,6′‐diethynyl‐2,2′‐dioctoxy‐1,1′‐binaphthyl in a Pd‐catalyzed Sonogashira reaction. The two polymers showed good solubility in some common solvents and were characterized with NMR, Fourier transform infrared, gel permeation chromatography, and circular dichroism spectroscopy. The application of the chiral monomers and polymers in the asymmetric addition of diethyl zinc to benzaldehyde was studied. The results indicated that P‐1 , P‐2 , and the monomer ( S )‐3,3′‐dibutyl‐1,1′‐binaphthol were efficient ligands in the asymmetric addition of diethyl zinc to benzaldehyde. The chiral polymer ligands P‐1 and P‐2 were more efficient than their monomeric version, ( S )‐3,3′‐dibutyl‐1,1′‐binaphthol, and could be easily recovered and reused without a loss of catalytic activity or enantioselectivity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007