A new polymer-supported BINOL ligand(4) was prepared by means of anchoring binaphthyl molecule (3) to aminoethylated polystyrene through a procedure of solid phase peptide synthesis. The key compound (R)-2,2′ -dihydroxy-1,1′ -binaphthyl-3-carboxylic acid(3) was prepared from R-BINOL by protection of hydroxyl groups and then reaction with n-butyllithium followed by carboxylation. By controlling the amount of BuLi, (3) was obtained in 55% overall yield. Ligand (4) was prepared through condensation of (3) with aminoethylated polystyrene in the presence of DCC and HOBt and found to have a loading of 0.40 mmol/g (by mass increase). The linkage between binaphthyl and aminoethylated polystyrene was indicated by a new absorption in IR spectrum of (4) at 1 644 cm-1 in comparing with what of the polystyrene. By mixing (4) with Ti(OiPr)4in dry CH2Cl2, a complex was easily prepared and this complex was found to be an efficient heterogeneous catalyst in asymmetric addition of diethylzinc to aldehydes. Optical active alcohols with up to 82 % ee were obtained from the asymmtric addition with high chemical yields when 20% of (4) was used. And when benzaldehyde was used as substrate, we found that enantioselectivity increased obviously when the amount of (4) used in reaction increased from 5 % to 20%;decreased the load of BINOL in ligand (4) reduced the ee of addition product; and R form of products was resulted.
1 1-联萘-2-酚 非均相催化剂 不对称加成反应