Catalysis Letters, Vol.142, No.6, 794-802, 2012
Asymmetric Organocatalytic Efficiency of Synthesized Chiral beta-Amino Alcohols in Ring-Opening of Glycidol with Phenols
A series of novel chiral beta-amino alcohols 3-5 and 7-10 were synthesized by regioselective ring opening of epoxides and chiral amines with a straightforward method in high yields (up to 99 %). Kinetic resolution of racemic glycidol with phenols was achieved by using chiral amino alcohols as organocatalysts. Amino alcohols 5, 8 and 10 exhibited the highest enantioselectivities with p-cresol, phenol, and p-methoxyphenol by 63, 65, 58 % ee, respectively. The moderate enantioselectivities were observed with catalyst 9b towards all the nucleophiles (34-48 % ee). The ee values of the desired 3-aryloxy-1,2-diols were determined by HPLC. This study presents an attractive tool for the synthesis of beta-blockers and structurally complex molecules.
Keywords:Epoxide ring opening;beta-Amino alcohols;Kinetic resolution;Organocatalysts;3-Aryloxy-1,2-propanediols