Small libraries of polymer-supported amino alcohols: An application to theenantioselective reduction of acetophenone by LAH

Starting from simple amino acid esters and Merrifield resins, a small libra ry of polymer-bound chiral-beta-amino alcohols can be prepared. By reaction with LiALH(4) the corresponding chiral reducing agents are obtained, havin g structural variations at both the alpha and beta positions. All supported reagents are able to reduce acetophenone to 1-phenylethanol. Enantioselect ivity is observed when the steric hindrance in the chiral fragment is incre ased. Best results are obtained for the supported derivative of alpha,alpha -diphenyl phenylalaninol.