Asymmetric synthesis by use of polymer-supported chiral activating agents

The authors have used a number of polymer-bound chiral amino alcohols or diols as polymeric complexing agents in asymmetric syntheses. The complexes obtained from chiral amino alcohols or diols and bound elements such as Zn, Ti, Al, B may behave as chiral activating agents. For example, the complex prepared from chiral amino alcohols and borane shows excellent catalytic activity in asymmetric hydride reductions. Many chiral reducing agents prepared from the polymeric chiral complex and borane showed excellent enantioselectivities not only in the asymmetric reduction of ketones but also in that of oxime ethers.