New soluble TADDOL-bearing polymers. Preparation and their use as Ti-complex catalysts for enantioselective addition of diethylzinc to benzaldehyde

摘要

Soluble polymer supported TADDOLs have been prepared by copolymerising the styryl derivative of TADDOL with styrene or N-isopropylacrylamide, NIPAAm, and the efficiency of their complexes with Ti(IV) as catalysts in enantioselective addition of Et_2Zn to benzaldehyde in toluene is reported. The copolymer with styrene gave very high yield (> 90%) and excellent enantioselectivity, 98% ee, while the copolymer with NIPAAm afforded a slightly lower yield (55%), but a very high ee (90%).