Functionalized major-groove and minor-groove chiral polybinaphthyls: Application in the asymmetric reaction of aldehydes with diethylzinc

A series of functionalized and optically active major-groove polybinaphthyls and minor-groove polybinaphthyls have been synthesized by using the Suzuki coupling reaction and have been spectroscopically characterized. The application of these chiral polymers in the asymmetric addition of diethylzinc to aldehydes has been studied. A minor-groove polybinaphthyl is found to be an excellent catalyst for the asymmetric reaction of diethylzinc with a number of aldehydes. The molecular weight and the molecular weight distribution of the polymer have little effects on the catalytic process. The chiral polymer can be easily recovered and reused without loss of catalytic activity as well as enantioselectivity, These rigid and sterically regular chiral polybinaphthyls represent a new generation of enantioselective polymeric catalysts, The reaction of the polybinaphthyls as well as certain monomeric binaphthyl molecules with diethylzinc has been investigated which has provided further information on the novel polymeric catalysts.