Poly(1,1′-bi-2-naphthol)s: Synthesis, Characterization, and Application in Lewis Acid Catalysis

摘要

6,6′-Dibromo-1,1′-bi-2-naphthol derivatives, where the hydroxyl groups are protected by alkyl, methoxymethyl, and acyl groups, have been polymerized using nickel(0) or nickel(II) complexes as catalysts. The molecular weights of the resulting polymers have been analyzed by gel permeation chromatography and laser light scattering. Hydrolysis of these polymers has produced the optically active poly(1,1′-bi-2-naphthol)s [poly(BINOL)s]. The poly(BINOL)s are soluble in basic water solution and have been characterized by NMR, IR, UV, and CD spectroscopic methods. The reaction of a (R)-poly(BINOL) with diethylaluminum chloride, trimethylaluminum, and titanium tetra-isopropoxide generates novel polymeric Lewis acid complexes. These complexes represent a new generation of polymeric catalysts where the catalytic centers are highly organized in an optically active and sterically regular polymer chain. When used to catalyze the Mukaiyama aldol condensation, the polymeric aluminum catalyst shows greatly enhanced catalytic activity over the monomeric complex.